Fusarium crown rot(FCR),predominantly caused by Fusarium pseudograminearum,has been listed as a Category Ⅱ disease in six provinces of China,posing a significant threat to wheat production.The phenylpyrrole fungicide...Fusarium crown rot(FCR),predominantly caused by Fusarium pseudograminearum,has been listed as a Category Ⅱ disease in six provinces of China,posing a significant threat to wheat production.The phenylpyrrole fungicide fludioxonil is a key agent for FCR control.Previous studies indicated that resistance to fludioxonil in F.pseudograminearum is primarily associated with altered expression levels of the FpOS1 gene,which encodes a hybrid histidine kinase.However,the roles of mutations in other FpOS genes and the molecular interactions between FpOS proteins and fludioxonil remain elusive.To address these gaps,we generated 16 fludioxonil-resistant mutants with heritable resistance traits by in vitro selection of four sensitive F.pseudograminearum isolates.These mutants exhibited high resistance levels,with resistance factors(RF)ranging from 633.73 to 8617.07.Compared to their parental isolates,the resistant mutants showed significantly reduced mycelial growth rate,sporulation capacity,and pathogenicity.They were also more sensitive to ionic,osmotic,and oxidative stresses and displayed compromised cell wall and membrane integrity.Fludioxonil demonstrated no cross-resistance with tebuconazole or pydiflumetofen;however,it exhibited weak positive crossresistance to pyraclostrobin and moderate positive cross-resistance to iprodione.Fludioxonil treatment significantly promoted glycerol synthesis and inhibited deoxynivalenol(DON)production in parental isolates,whereas these regulatory effects were markedly attenuated in the resistant mutants.Mutation analysis identified mutation sites in FpOS1,FpOS4,and FpOS5 genes,with a lower mutation frequency in FpOS1 and no mutations detected in FpOS2.Molecular docking indicated that amino acid substitutions in FpOS4 and FpOS5 significantly reduced the binding affinity of fludioxonil to these target proteins.In conclusion,F.pseudograminearum poses a moderate risk of resistance to fludioxonil.Point mutations in FpOS4 and FpOS5 genes emerge as key molecular drivers of resistance,likely by diminishing the binding affinity between the fungicide and its proteins.This study clarifies the molecular basis of fludioxonil resistance in F.pseudograminearum and provides a scientific rationale for the judicious use of this fungicide in managing FCR.展开更多
OsMAPK6 plays a critical role in regulating rice growth,development,and stress responses.However,the embryonic lethality associated with loss-of-function mutations prevents the generation of homozygous mutant seeds,si...OsMAPK6 plays a critical role in regulating rice growth,development,and stress responses.However,the embryonic lethality associated with loss-of-function mutations prevents the generation of homozygous mutant seeds,significantly hindering functional studies of this gene.Although the weak mutant dsg1 has offered valuable insights into OsMAPK6 function,its extremely low seed-setting rate limits its use for detailed genetic analysis.Here,we employed prime editing to perform precise multi-site modifications at the C-terminus of OsMAPK6,generating a series of osmapk6 mutants with truncated proteins of varying lengths.Among these,the osmapk6(379)and osmapk6(383)mutants exhibited phenotypic defects similar to dsg1,while osmapk6(386)showed a significantly improved seed-setting rate despite persistent developmental defects.Through phenotypic characterization and protein functional analysis,we further clarified how different C-terminal deletion lengths affect plant growth,development,stress responses,and OsMAPK6 protein function.In summary,this study elucidates the importance of the OsMAPK6 C-terminus in rice biology and provides a fertile weak mutant with enhanced seed production,offering a valuable genetic resource for future research on OsMAPK6.展开更多
With the increasing accumulation of plastic pollutants in various environments,research on microorganisms(including bacteria,fungi,and algae)with plastic degradation capabilities has gained significant attention.Howev...With the increasing accumulation of plastic pollutants in various environments,research on microorganisms(including bacteria,fungi,and algae)with plastic degradation capabilities has gained significant attention.However,only a limited number of microbial plastic-degrading enzymes have been identified to date.This highlights that the degradation mechanisms employed by many plastic-degrading microorganisms,particularly filamentous fungi,remain insufficiently explored.In this study,we utilized a versatile fungal plasmid(pCT74)to express green fluorescent protein(GFP)in a marine-derived fungus Alternaria alternata strain FB1 with plastic degradation capabilities.Upon evaluating the degradation effect of polyester-type polyurethane(PU)film,we observed that different transformants exhibited three kinds of activities(the same,reduced,or enhanced degradation capability)compared to the FB1 wild-type strain.Further analysis of the plasmid fragment insertion sites in different transformants revealed that pCT74 integrates randomly into the genome of the host fungus.Notably,a direct correlation was found between the plasmid insertion site and the degradation capability of the corresponding transformant.Our findings not only redefine the potential applications of plasmid pCT74 in filamentous fungi but also show a novel research approach to identifying key enzymes involved in plastic degradation by fungi.展开更多
KRAS is a critical proto-oncogene and molecular switch that is frequently mutated in human cancers.Oncogenic mutations,primarily at codons 12,13,and 61,lock KRAS into a GTPbound active state,thus resulting in constitu...KRAS is a critical proto-oncogene and molecular switch that is frequently mutated in human cancers.Oncogenic mutations,primarily at codons 12,13,and 61,lock KRAS into a GTPbound active state,thus resulting in constitutive signaling through downstream effectors such as RAF and phosphoinositide 3-kinase(PI3K)1.These alterations are highly prevalent in pancreatic cancer,colorectal cancer(CRC),and non-small cell lung cancer(NSCLC),and they drive tumor initiation,progression,and therapy resistance.展开更多
[Objective] The aim of this study was to screen Saccharomyces for glutathione over-production. [Method] Ethionine-resistant mutants were obtained through UV mutagenesis and rational screening. [Result] A high GSH-prod...[Objective] The aim of this study was to screen Saccharomyces for glutathione over-production. [Method] Ethionine-resistant mutants were obtained through UV mutagenesis and rational screening. [Result] A high GSH-producing strain HSJB1 was isolated from soil, and the biomass for this strain by flask shaking fermentation was 3.87 g/L while the GSH yield was 91.87 mg/L. According to the morphological, physiological and biochemical characteristics of cells, this strain was primarily identified as Saccharomyces cerevisiae. An ethionine-resistant mutant YBS77 was obtained through UV mutagenesis of the original strain HSJB1, and the biomass for this strain by flask shaking fermentation was 7.60 g dry cell weight/L while the GSH yield was 211.96 mg/L. [Conclusion] The biomass of the mutant obtained by breeding is increased by 96.38% than that of the original strain, and the GSH yield of the mutant obtained by breeding is increased by 130.72% than that from the original strain, which indicates that the breeding method is feasible.展开更多
[Objective] The aim was to improve the genetic property of peppers, the mutant population of Capsicum annuum L cultivar ＂6421＂ was constructed. [Method] The seeds of ＂6421＂ were treated with 0.2% to 1.2% ethyl met...[Objective] The aim was to improve the genetic property of peppers, the mutant population of Capsicum annuum L cultivar ＂6421＂ was constructed. [Method] The seeds of ＂6421＂ were treated with 0.2% to 1.2% ethyl methane sulfonate to identified LD50, and then 10 000 LD^o of treated seeds were sowed to construct mutant population. The agronomic characters and genetic regularity of dwarf mutants in M4 generation were analyzed. [Result] Our results showed that GR and SSR were 45.2% and 40.2% respectively at 1.0% EMS, close to LD50, with GI （17.6） and seed Ⅵ （19.7） being half of that of control; 562 M4 mutants were identified in 2015, and the mutation could be characterized according 11 major categories and 32 subcategories; Simultaneously, we found that plant height, plant width, diameter of mainstem, length of main-stem, the number of main-stem nodes and branch of lines E29, E58, E142 and E312 were all significantly different from that of the control. The mutation of lines E29, E58 and E312 was all controlled by a single recessive gene. [Conclusionl The study first created a pepper mutant population, which provides not only the germplasm resources for further breeding but also direct and effective materials for genomic study of the pepper.展开更多
[Objective] The 15urpose was to seek for the different phenotypes between wild type and Arabidopsis Mutants in response to CO2. [Method] The epidermis bioassays and seed germination test were carried out to analyze th...[Objective] The 15urpose was to seek for the different phenotypes between wild type and Arabidopsis Mutants in response to CO2. [Method] The epidermis bioassays and seed germination test were carried out to analyze the physiological characteristics of two Arabidopsis mu- tants and their wild type. [Result] There existed distinct differences in stomata apertures, water loss and leaf temperature compared with wild type except for stomata density. In addition, seed germination test on the medium indicated that cdfl was insensitive to ABA, mannitol and NaCI, but cdsl performed contrary to cdil. [ Conclusion] There are some different physiological characteristics between wild type and mutants.展开更多
[Objective] The aim was to identify the mutants of millet Changnong35 induced by different concentrations of EMS, so as to construct a millet mutant library. [Method] Foxtail millet cultivar Changnong35 which is widel...[Objective] The aim was to identify the mutants of millet Changnong35 induced by different concentrations of EMS, so as to construct a millet mutant library. [Method] Foxtail millet cultivar Changnong35 which is widely used in agricultural production, was treated with 0.8% and 1.0% EMS; and then seven traits of mutants were investigated analyzed, to classify the mutants into different groups. [Result] 282 mutants in the M1 generation related to plant type were obtained, of which, 100 mutant plants treated with 0.8% EMS can be divided into 10 groups; 182 mutant plants obtained by using 1.0% EMS can be divided into 17 groups. The analysis results of the mature plant type traits of the M1 Generation showed that, plant height, diameter of stem under spike, diameter of the first internode under spike and internode number of the mutants treated with 1.0% EMS were significantly different from those of control, while those of mutants treated with 0.8% EMS did not show significant difference from those of control. [Conclusion] The inducing with 1.0% EMS was more conducive to obtain a large number and different types of mutants from Changnong35.展开更多
Comparative studies of absorption spectra of phycobiliproteins of Gracilaria lemaneiformis Greville and its pigmental mutants were conducted in this study. The results showed that the absorption spectra of phycoerythr...Comparative studies of absorption spectra of phycobiliproteins of Gracilaria lemaneiformis Greville and its pigmental mutants were conducted in this study. The results showed that the absorption spectra of phycoerythrins ( PE) from different material changed significantly, while those of phycocyanins (PC) and allophycocyanins (APC) were basically similar. In order to disclose the essence of die difference, partial sequences of die subunit genes of PE of Qingdao strain of G. lemaneiformis (qd) and its pigmental mutants were determined. The amino acid sequences were deduced and used to explain spectral shifts of PE from the pigmental mutants. The amino acid sequences of PE resembled each other, and several residues changed among qd and its pigmental mutants. Residue substitutions were found in a region consisting of amino acids which determined are secondary structure and subunits interactions, thus might influence the confirmation and interaction of subunits, and further caused spectral deviation.展开更多
Ethyl methane-sulfonate (EMS)-mutagenized Arabidopsis M-2 populations were screened in low-K+ medium using the root-bending assay. Forty-two putative low-k(+)-tolerant (lkt) mutants were selected from 150 000 tested M...Ethyl methane-sulfonate (EMS)-mutagenized Arabidopsis M-2 populations were screened in low-K+ medium using the root-bending assay. Forty-two putative low-k(+)-tolerant (lkt) mutants were selected from 150 000 tested M-2 seedlings, and two of these mutants maintained their low-K+-tolerant phenotype in their M-3 generations, respectively. Genetic analysis showed that either one of these two mutants has a monogenic recessive mutation in a nuclear gene, and that the two mutations in two independent mutants are allelic to each other.展开更多
[Objective] M3 progenies of Jingnong 6 variety induced by EMS chemical mutagenesis were screened and identified for obtaining valuable mutation material.[Method] Azuki bean cultivar Jingnong 6 was treated with EMS.The...[Objective] M3 progenies of Jingnong 6 variety induced by EMS chemical mutagenesis were screened and identified for obtaining valuable mutation material.[Method] Azuki bean cultivar Jingnong 6 was treated with EMS.The mutation rate,mutation types,agronomic traits and yield components of the leaf mutants were analyzed.[Result] The results showed that there is the most abundant mutational type of leaf shape and the highest mutation frequency treated with 0.9% EMS for 24 hours.Comprehensive analysis on agronom...展开更多
[Objective] The research aimed to reveal the functions of NAC and UBA domains in Peatl＇s thermal stability. [Method] Fusion expression vectors of Pearl protein and the 3 deletion mutants were constructed. The recombi...[Objective] The research aimed to reveal the functions of NAC and UBA domains in Peatl＇s thermal stability. [Method] Fusion expression vectors of Pearl protein and the 3 deletion mutants were constructed. The recombinant plasmids were induced by IPTG and the target proteins （Peatl, Peatl-△CD99,Peatl-△ND49 and Pearl-△ND108 ）were expressed obtained by AKTA and its thermal stability was analyzed. [Result] The research found that 3 deletion mutants have good thermal stability like Pearl. [Conclusion] The research demonstrated that the coexistence of NAC or UBA domains is not necessary to thermal stability of Pearl protein , and they may give the protein particular stability structure seperately.展开更多
AIM:To investigate precore/basal core promoter(PC/BCP) mutants throughout hepatitis B virus(HBV) infection and to determine their relationship to hepatitis B early antigen(HBeA g) titers.METHODS:We enrolled 191 patien...AIM:To investigate precore/basal core promoter(PC/BCP) mutants throughout hepatitis B virus(HBV) infection and to determine their relationship to hepatitis B early antigen(HBeA g) titers.METHODS:We enrolled 191 patients in various stages of HBV infection at the Huashan Hospital and the Taizhou Municipal Hospital from 2010 to 2012.None of the patients received antiviral therapy.HBV DNA from serum,was quantified by real-time PCR.The HBV genotype was determined by direct sequencing of the S gene.We used the Simpleprobe ultrasensitivequantitative method to detect PC/BCP mutants in each patient.We compared the strain number,percentage,and the changes in PC/BCP mutants in different phases,and analyzed the relationship between PC/BCP mutants and HBe Ag by multiple linear regression and logistic regression.RESULTS:Patients with HBV infection(n = 191) were assigned to groups by phase:Immune tolerance(IT) = 55,Immune clearance(IC) = 67,Low-replicative(LR) = 49,and HBeA g-negative hepatitis(ENH) = 20.Of the patients(male,112; female,79) enrolled,122 were HBe Ag-positive and 69 were HBe Ag-negative.The median age was 33 years(range:18-78 years).PC and BCP mutation detection rates were 84.82%(162/191) and 96.86%(185/191),respectively.In five HBe Ag-negative cases,we detected double mutation G1896A/G1899 A.The logarithm value of PC mutant quantities(log10 PC) significantly differed in IT,IC,and LR phases,as well as in the ENH phase(F = 49.350,P < 0.001).The logarithm value of BCP mutant quantities(log10 BCP) also differed during the four phases(F = 25.530,P < 0.001).Log10 PC and log10 BCP values were high in the IT and IC phases,decreased in the LR phase,and increased in the ENH phase,although the absolute value at this point remained lower than that in the IT and IC phases.PC mutant quantity per total viral load(PC%) and BCP mutant quantity per total viral load(BCP%) differed between phases(F = 20.040,P < 0.001; F = 10.830,P < 0.001),with PC% and BCP% gradually increasing in successive phases.HBeA g titers negatively correlated with PC%(Spearman's rho =-0.354,P < 0.001) and BCP%(Spearman's rho =-0.395,P < 0.001).The negative correlation between PC% and HBeA g status was significant(B =-5.281,P = 0.001),but there was no such correlation between BCP% and HBeA g status(B =-0.523,P = 0.552).CONCLUSION:PC/BCP mutants become predominant in a dynamic and continuous process.Log10 PC,log10 BCP,PC% and BCP% might be combined to evaluate disease progression.PC% determines HBeA g status.展开更多
The clustered regularly interspaced short palindromic repeats(CRISPR)/Cas9 technology has been widely utilized for knocking out genes involved in various biological processes in zebrafish. Despite this technology is e...The clustered regularly interspaced short palindromic repeats(CRISPR)/Cas9 technology has been widely utilized for knocking out genes involved in various biological processes in zebrafish. Despite this technology is efficient for generating different mutations, one of the main drawbacks is low survival rate during embryogenesis when knocking out some embryonic lethal genes. To overcome this problem, we developed a novel strategy using a combination of CRISPR/Cas9 mediated gene knockout with primordial germ cell(PGC) transplantation(PGCT) to facilitate and speed up the process of zebrafish mutant generation, particularly for embryonic lethal genes. Firstly, we optimized the procedure for CRISPR/Cas9 targeted PGCT by increasing the efficiencies of genome mutation in PGCs and induction of PGC fates in donor embryos for PGCT. Secondly, the optimized CRISPR/Cas9 targeted PGCT was utilized for generation of maternal-zygotic(MZ) mutants of tcf7l1a(gene essential for head development), pou5f3(gene essential for zygotic genome activation) and chd(gene essential for dorsal development) at F1 generation with relatively high efficiency. Finally, we revealed some novel phenotypes in MZ mutants of tcf7l1 a and chd, as MZtcf7l1 a showed elevated neural crest development while MZchd had much severer ventralization than its zygotic counterparts. Therefore, this study presents an efficient and powerful method for generating MZ mutants of embryonic lethal genes in zebrafish. It is also feasible to speed up the genome editing in commercial fishes by utilizing a similar approach by surrogate production of CRISPR/Cas9 targeted germ cells.展开更多
Tissue culture has been widely used for mass propagation of Phalaenopsis. However, somaclonal variation occurred during micropropagation process posed a severe problem by affecting product quality. In this study, wild...Tissue culture has been widely used for mass propagation of Phalaenopsis. However, somaclonal variation occurred during micropropagation process posed a severe problem by affecting product quality. In this study, wild type and peloric flower buds of Phalaenopsis hybrids derived from flower stalk nodal culture were used for cDNA-RAPD and cDNA suppression subtractive hybridization analyses in order to study their genetic difference in terms of expressed sequence tags. A total of 209 ESTs from normal flower buds and 230 from mutants were sequenced. These ESTs sequences can be grouped into several functional categories involved in different cellular processes including metabolism, signal transduction, transcription, cell growth and division, protein synthesis, and protein localization, and into a subcat- egory of proteins with unknown function. Cymbidium mosaic virus transcript was surprisingly found expressed fre- quently in the peloric mutant of P. Little Mary. Real-time RT-PCR analysis on selected ESTs showed that in mutant flower buds, a bZIP transcription factor (TGA1a-like protein) was down-regulated, while up-regulated genes include auxin-regulated protein kinase, cyclophilin, and TCP-like genes. A retroelement clone was also preferentially expressed in the peloric mutant flowers. On the other hand, ESTs involved in DNA methylation, chromatin remodeling and post- transcriptional regulation, such as DNA methyltransferase, histone acetyltransferase, ERECTA, and DEAD/DEAH RNA helicase, were enriched in normal flower buds than the mutants. The enriched transcripts in the wild type indicate the down regulation of these transcripts in the mutants, and vice versa. The potential roles of the analyzed transcripts in the development of Phalaenopsis flowers are discussed.展开更多
It is established that different stresses cause signal-specific changes in cellular Ca2 ~ level, which function as messengers in modulating diverse physiological processes. These calcium signals are important for stre...It is established that different stresses cause signal-specific changes in cellular Ca2 ~ level, which function as messengers in modulating diverse physiological processes. These calcium signals are important for stress adaptation. Though numbers of downstream components of calcium signal cascades have been identified, upstream events in calcium signal remain elusive, specifically components required l＇~~r calcium signal generation due to the lack of high-throughput genetic assay. Here, we report the development of an easy and efficient method in a forward genetic screen for Ca2＋ signals-deficient mutants in Arahidopsis thaliana. Using this method, 121 mutants with disordered NaCI- and H=O2-induced Ca2＋ signals are isolated.展开更多
In this study, two ploidy mutant lines ofMyrica rubra cv. Dongkui （DK） were identiifed and named as DB1 and DB2. The lforal organ, leaf cel structure, ploidy, and number of chromosomes of the two mutants were invest...In this study, two ploidy mutant lines ofMyrica rubra cv. Dongkui （DK） were identiifed and named as DB1 and DB2. The lforal organ, leaf cel structure, ploidy, and number of chromosomes of the two mutants were investigated. Meanwhile, anthocyanin contents at different developmental stages were analyzed, and the Cy-3-glu contents of DB1 and DB2 at the ful ripe stages are signiifcantly higher than that of DK by 27.84 and 23.51%, respectively. Furthermore, 6 RNA libraries at two developmental stages （young fruit stage and ful ripe stage） were built for RNA-Seq. By mapping to the reference database, 28407, 28043, and 28683 genes were detected in the young fruit of DB1, DB2, and DK, respectively, while 28040, 22256, and 27351 genes were detected in the ful ripe stage, respectively. There were 281 differentialy expressed genes between DB1 and DK, with 123 and 158 genes up-regulated and down-regulated, respectively, and 47 differentialy expressed genes between DB2 and DK, of which 8 and 39 genes were up-regulated and down-regulated. Using real-time PCR, the expression levels of the eight functional genes at different developmental stages of the fruit were also analyzed. These comprehensive analyses showed that both mutants are different from DK, which is the result of natural doubling of ploidy, thereby generating a pleiotropic effect. As we known, it is the ifrst report to study the relationship between bayberry ploidy alterations and genes involved in regulation of fruit mutations, which wil help to identify the morphological and cytological characteristics ofM. rubragermplasm, and provide a theoretical basis and technical support for genetic improvement and creation of breeding resources.展开更多
The two mutants idr1-1 and 297-28, which were obtained from the radiation mutation of HD297 and IAPAR9, were used as experimental materials in this study for a 2-year(2012 and 2013) experiment about field drought resi...The two mutants idr1-1 and 297-28, which were obtained from the radiation mutation of HD297 and IAPAR9, were used as experimental materials in this study for a 2-year(2012 and 2013) experiment about field drought resistance identification in Beijing, China. Key agronomic traits and water-related physiological indexes were observed and measured, including the leaf anti-dead level(LADL), days to heading, plant height, setting percentage, aboveground biomass, leaf water potential(LWP), net photosynthetic rate(Pn) and transpiration rate. The results showed that the mutant idr1-1 that was under drought stress(DS) conditions for 2 years had the highest LADL grades(1.3 and 2.0) among all the materials, and they were 2–3 grades stronger than the wild-type IAPAR9 with an average that was 21.4% higher for the setting percentage than the wild type. Compared with the IAPAR9 for the 2-year average delay in the days to heading and the reduction rates in the plant height, setting percentage, and aboveground biomass under DS compared with the well-watered(WW) treatment, idr1-1 showed 3.2% less delay and 19.1, 16.4, and 6.1% less reduction, respectively. The idr1-1 in the LWP always exhibited the highest performance among all the materials. The Pn of idr1-1 under severe and mild DS comparing with that under WW was slightly decreased and even slightly increased, respectively, leading to an average reduction rate of only 0.92%, which was 26.93% less than that of IAPAR9. Under the severe DS, idr1-1 still showed the highest value of 16.88 μmol CO2 m–2 s–1 among all the materials and was significantly higher than that of IAPAR9(11.66 μmol CO2 m–2 s–1). Furthermore, only idr1-1 had the increased and the highest transpiration rate values(7.6 and 6.04 mmol H2 O m–2 s–1) under both mild and severe DS compared with the values under WW, when the transpiration rate of all the other materials significantly decreased. By contrast, the 297-28 in terms of the LADL grade under DS was the lowest(7.0), and it was four grades weaker than its wildtype HD297 and even one grade weaker than the drought-sensitive paddy rice SN265. For the 2-year average reduction rates in aboveground biomass and plant heights under DS compared with those under the WW, 297-28 was 31.6 and 31.8% higher than HD297, respectively. Meanwhile, 297-28 showed the worst performance for the LWP, Pn, and transpiration rate. These results suggest that idr1-1 might be a superior drought tolerant mutant of upland rice found in China. It has a strong ability to maintain and even enhance leaf transpiration while maintaining a high plant water potential under DS, thus supporting a high Pn and alleviating the delay in agronomic trait development and yield loss effectively. 297-28 is a much more highly drought-sensitive mutant that is even more sensitive than paddy rice varieties. The two mutants could be used as drought tolerance controls for rice germplasm identification and the drought resistant mechanism studies in the future. idr1-1 is also suitable for breeding drought-tolerant and lodging-resistant high-yield rice varieties.展开更多
The resistance of soybean(Glycine max(L.) Merr.) to soybean cyst nematode(SCN, Heterodera glycines Ichinohe), which is a devastating pathogen in soybean production and causes a large quantity of annual yield loss worl...The resistance of soybean(Glycine max(L.) Merr.) to soybean cyst nematode(SCN, Heterodera glycines Ichinohe), which is a devastating pathogen in soybean production and causes a large quantity of annual yield loss worldwide, can shift during the long-term interaction and domestication. It is vital to identify more new resistance genetic sources for identification of novel genes underlying resistance to SCN for management of this pathogen. In the present study, first, two ethane methylsulfonate-mutagenesis soybean M2 populations of PI 437654, which shows a broad resistance to almost all of SCN races, and Zhonghuang 13, which is a soybean cultivar in China conferring strong resistance to lodging, were developed. Many types of morphological phenotypes such as four-and five-leaflet leaves were observed from these two soybean M2 populations. Second, 13 mutants were identified and confirmed to exhibit alteration of resistance to SCN race 4 through the forward genetic screening of 400 mutants of the PI 437654 M2 population, the rate of mutants with alteration of SCNinfection phenotype is 3.25%. Third, these identified mutants were further verified not to show any changes in the genomic sequences of the three known SCN-resistant genes, GmSHMT08, GmSNAP18 and GmSANP11, compared to the wildtype soybean; and all of them were still resistant to SCN race 3 similar to the wild-type soybean. Taken together, we can conclude that the 13 mutants identified in the present study carry the mutations of the new gene(s) which contribute(s) to the resistance to SCN race 4 in PI 437654 and can be potentially used as the genetic soybean sources to further identify the novel SCN-resistant gene(s).展开更多
AIM： To conduct a retrospective study in 400 chronic hepatitis B patients in order to identify hepatitis B viral factors associated with complications of liver disease or development of hepatocellular carcinoma. METH...AIM： To conduct a retrospective study in 400 chronic hepatitis B patients in order to identify hepatitis B viral factors associated with complications of liver disease or development of hepatocellular carcinoma. METHODS： The mean follow-up time was 83.6 ± 39.6 mo. Alpha-fetoprotein test and abdominal ultrasound were used for cancer surveillance. Hepatitis B basal core promoter mutants, precore mutants, genotypes, hepatitis B viral DNA （HBV DNA） level and hepatitis B e antigen （HBeAg） were measured. Univariate analysis and logistic regression were used to assess odds ratios for viral factors related to liver deaths and hepatocellular carcinoma development. RESULTS： During follow-up, 38 patients had liver deaths not related to hepatocellular carcinoma. On multivariate analysis, older age [odds ratio： 95.74 （12.13-891.31）, P 〈 0.0001], male sex [odds ratio： 7.61 （2.20-47.95）; P = 0.006], and higher Iogzo HBV DNA [odds ratio： 4.69 （1.16-20.43）; P 〈 0.0001] were independently predictive for these liver related deaths. Also, 31 patients developed hepatocellular carcinoma. Multivariate analysis showed that older age [odds ratio： 26.51 （2.36-381.47）; P = 0.007], presence of precore mutants [odds ratio： 4.23 （1.53-19.58）, P = 0.02] and presence of basal core promoter mutants [odds ratio： 2.93 （1.24-7.57）; P = 0.02] were independent predictors for progression to hepatocellular carcinoma. CONCLUSION： Our results show that high levels of baseline serum HBV DNA are associated with non- hepatocellular carcinoma-related deaths of liver failure, while genetic mutations in the basal core promoter and precore regions are predictive for development of hepatocellular carcinoma.展开更多
基金Supported by Funding from the Henan Provincial Scientific and Technological Breakthrough Project(No.242102111113).
文摘Fusarium crown rot(FCR),predominantly caused by Fusarium pseudograminearum,has been listed as a Category Ⅱ disease in six provinces of China,posing a significant threat to wheat production.The phenylpyrrole fungicide fludioxonil is a key agent for FCR control.Previous studies indicated that resistance to fludioxonil in F.pseudograminearum is primarily associated with altered expression levels of the FpOS1 gene,which encodes a hybrid histidine kinase.However,the roles of mutations in other FpOS genes and the molecular interactions between FpOS proteins and fludioxonil remain elusive.To address these gaps,we generated 16 fludioxonil-resistant mutants with heritable resistance traits by in vitro selection of four sensitive F.pseudograminearum isolates.These mutants exhibited high resistance levels,with resistance factors(RF)ranging from 633.73 to 8617.07.Compared to their parental isolates,the resistant mutants showed significantly reduced mycelial growth rate,sporulation capacity,and pathogenicity.They were also more sensitive to ionic,osmotic,and oxidative stresses and displayed compromised cell wall and membrane integrity.Fludioxonil demonstrated no cross-resistance with tebuconazole or pydiflumetofen;however,it exhibited weak positive crossresistance to pyraclostrobin and moderate positive cross-resistance to iprodione.Fludioxonil treatment significantly promoted glycerol synthesis and inhibited deoxynivalenol(DON)production in parental isolates,whereas these regulatory effects were markedly attenuated in the resistant mutants.Mutation analysis identified mutation sites in FpOS1,FpOS4,and FpOS5 genes,with a lower mutation frequency in FpOS1 and no mutations detected in FpOS2.Molecular docking indicated that amino acid substitutions in FpOS4 and FpOS5 significantly reduced the binding affinity of fludioxonil to these target proteins.In conclusion,F.pseudograminearum poses a moderate risk of resistance to fludioxonil.Point mutations in FpOS4 and FpOS5 genes emerge as key molecular drivers of resistance,likely by diminishing the binding affinity between the fungicide and its proteins.This study clarifies the molecular basis of fludioxonil resistance in F.pseudograminearum and provides a scientific rationale for the judicious use of this fungicide in managing FCR.
基金supported by the National Natural Science Foundation of China(Grant Nos.32441024,32572315,and U25A20674)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2021229)+1 种基金the Heilongjiang Key Research and Development Program,China(Grant No.2025ZX04B02)the Young Scientist Group Project of Northeast Institute of Geography and Agroecology,Chinese Academy of Sciences(Grant No.2023QNXZ02).
文摘OsMAPK6 plays a critical role in regulating rice growth,development,and stress responses.However,the embryonic lethality associated with loss-of-function mutations prevents the generation of homozygous mutant seeds,significantly hindering functional studies of this gene.Although the weak mutant dsg1 has offered valuable insights into OsMAPK6 function,its extremely low seed-setting rate limits its use for detailed genetic analysis.Here,we employed prime editing to perform precise multi-site modifications at the C-terminus of OsMAPK6,generating a series of osmapk6 mutants with truncated proteins of varying lengths.Among these,the osmapk6(379)and osmapk6(383)mutants exhibited phenotypic defects similar to dsg1,while osmapk6(386)showed a significantly improved seed-setting rate despite persistent developmental defects.Through phenotypic characterization and protein functional analysis,we further clarified how different C-terminal deletion lengths affect plant growth,development,stress responses,and OsMAPK6 protein function.In summary,this study elucidates the importance of the OsMAPK6 C-terminus in rice biology and provides a fertile weak mutant with enhanced seed production,offering a valuable genetic resource for future research on OsMAPK6.
基金Supported by the Science and Technology Innovation Project of Laoshan Laboratory(Nos.2022QNLM030004-3,LSKJ202203103)the NSFC Innovative Group Grant(No.42221005)+5 种基金the Key Collaborative Research Program of the Alliance of International Science Organizations(No.ANSO-CR-KP-2022-08)the Shandong Provincial Natural Science Foundation(No.ZR2021ZD28)the Major Research Plan of the National Natural Science Foundation(No.92351301)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA22050301)the Taishan Scholars Program(No.tstp20230637)the Qingdao Natural Science Foundation(No.23-2-1-182-zyyd-jch)。
文摘With the increasing accumulation of plastic pollutants in various environments,research on microorganisms(including bacteria,fungi,and algae)with plastic degradation capabilities has gained significant attention.However,only a limited number of microbial plastic-degrading enzymes have been identified to date.This highlights that the degradation mechanisms employed by many plastic-degrading microorganisms,particularly filamentous fungi,remain insufficiently explored.In this study,we utilized a versatile fungal plasmid(pCT74)to express green fluorescent protein(GFP)in a marine-derived fungus Alternaria alternata strain FB1 with plastic degradation capabilities.Upon evaluating the degradation effect of polyester-type polyurethane(PU)film,we observed that different transformants exhibited three kinds of activities(the same,reduced,or enhanced degradation capability)compared to the FB1 wild-type strain.Further analysis of the plasmid fragment insertion sites in different transformants revealed that pCT74 integrates randomly into the genome of the host fungus.Notably,a direct correlation was found between the plasmid insertion site and the degradation capability of the corresponding transformant.Our findings not only redefine the potential applications of plasmid pCT74 in filamentous fungi but also show a novel research approach to identifying key enzymes involved in plastic degradation by fungi.
基金supported by the National Natural Science Foundation of China(Grant Nos.82472677,82404653,U25A20103,and 223B2704)the Natural Science Foundation of Shanghai(Grant No.23ZR1418900)the Natural Science Foundation of Chongqing(Grant No.CSTB2023NSCQ-MSX0367).
文摘KRAS is a critical proto-oncogene and molecular switch that is frequently mutated in human cancers.Oncogenic mutations,primarily at codons 12,13,and 61,lock KRAS into a GTPbound active state,thus resulting in constitutive signaling through downstream effectors such as RAF and phosphoinositide 3-kinase(PI3K)1.These alterations are highly prevalent in pancreatic cancer,colorectal cancer(CRC),and non-small cell lung cancer(NSCLC),and they drive tumor initiation,progression,and therapy resistance.
基金Supported by Scientific Research Project of Liaoning Educational Department(20060154)Initial Funds for Doctors in Dalian Nationalities University(20066206)~~
文摘[Objective] The aim of this study was to screen Saccharomyces for glutathione over-production. [Method] Ethionine-resistant mutants were obtained through UV mutagenesis and rational screening. [Result] A high GSH-producing strain HSJB1 was isolated from soil, and the biomass for this strain by flask shaking fermentation was 3.87 g/L while the GSH yield was 91.87 mg/L. According to the morphological, physiological and biochemical characteristics of cells, this strain was primarily identified as Saccharomyces cerevisiae. An ethionine-resistant mutant YBS77 was obtained through UV mutagenesis of the original strain HSJB1, and the biomass for this strain by flask shaking fermentation was 7.60 g dry cell weight/L while the GSH yield was 211.96 mg/L. [Conclusion] The biomass of the mutant obtained by breeding is increased by 96.38% than that of the original strain, and the GSH yield of the mutant obtained by breeding is increased by 130.72% than that from the original strain, which indicates that the breeding method is feasible.
基金Supported by Natural Science Foundation of Hunan(2016JJ6064)China Agriculture Research System(CARS-25-A-8)~~
文摘[Objective] The aim was to improve the genetic property of peppers, the mutant population of Capsicum annuum L cultivar ＂6421＂ was constructed. [Method] The seeds of ＂6421＂ were treated with 0.2% to 1.2% ethyl methane sulfonate to identified LD50, and then 10 000 LD^o of treated seeds were sowed to construct mutant population. The agronomic characters and genetic regularity of dwarf mutants in M4 generation were analyzed. [Result] Our results showed that GR and SSR were 45.2% and 40.2% respectively at 1.0% EMS, close to LD50, with GI （17.6） and seed Ⅵ （19.7） being half of that of control; 562 M4 mutants were identified in 2015, and the mutation could be characterized according 11 major categories and 32 subcategories; Simultaneously, we found that plant height, plant width, diameter of mainstem, length of main-stem, the number of main-stem nodes and branch of lines E29, E58, E142 and E312 were all significantly different from that of the control. The mutation of lines E29, E58 and E312 was all controlled by a single recessive gene. [Conclusionl The study first created a pepper mutant population, which provides not only the germplasm resources for further breeding but also direct and effective materials for genomic study of the pepper.
文摘[Objective] The 15urpose was to seek for the different phenotypes between wild type and Arabidopsis Mutants in response to CO2. [Method] The epidermis bioassays and seed germination test were carried out to analyze the physiological characteristics of two Arabidopsis mu- tants and their wild type. [Result] There existed distinct differences in stomata apertures, water loss and leaf temperature compared with wild type except for stomata density. In addition, seed germination test on the medium indicated that cdfl was insensitive to ABA, mannitol and NaCI, but cdsl performed contrary to cdil. [ Conclusion] There are some different physiological characteristics between wild type and mutants.
基金Supported by Doctoral Fund of Shanxi Academy of Agricultural Sciences for Construction and Application of Mutant Library of Changnong 35 Induced with EMS(YBSJJ1001)Project of Modern Agricultural Industrial Technology System for Millet~~
文摘[Objective] The aim was to identify the mutants of millet Changnong35 induced by different concentrations of EMS, so as to construct a millet mutant library. [Method] Foxtail millet cultivar Changnong35 which is widely used in agricultural production, was treated with 0.8% and 1.0% EMS; and then seven traits of mutants were investigated analyzed, to classify the mutants into different groups. [Result] 282 mutants in the M1 generation related to plant type were obtained, of which, 100 mutant plants treated with 0.8% EMS can be divided into 10 groups; 182 mutant plants obtained by using 1.0% EMS can be divided into 17 groups. The analysis results of the mature plant type traits of the M1 Generation showed that, plant height, diameter of stem under spike, diameter of the first internode under spike and internode number of the mutants treated with 1.0% EMS were significantly different from those of control, while those of mutants treated with 0.8% EMS did not show significant difference from those of control. [Conclusion] The inducing with 1.0% EMS was more conducive to obtain a large number and different types of mutants from Changnong35.
文摘Comparative studies of absorption spectra of phycobiliproteins of Gracilaria lemaneiformis Greville and its pigmental mutants were conducted in this study. The results showed that the absorption spectra of phycoerythrins ( PE) from different material changed significantly, while those of phycocyanins (PC) and allophycocyanins (APC) were basically similar. In order to disclose the essence of die difference, partial sequences of die subunit genes of PE of Qingdao strain of G. lemaneiformis (qd) and its pigmental mutants were determined. The amino acid sequences were deduced and used to explain spectral shifts of PE from the pigmental mutants. The amino acid sequences of PE resembled each other, and several residues changed among qd and its pigmental mutants. Residue substitutions were found in a region consisting of amino acids which determined are secondary structure and subunits interactions, thus might influence the confirmation and interaction of subunits, and further caused spectral deviation.
文摘Ethyl methane-sulfonate (EMS)-mutagenized Arabidopsis M-2 populations were screened in low-K+ medium using the root-bending assay. Forty-two putative low-k(+)-tolerant (lkt) mutants were selected from 150 000 tested M-2 seedlings, and two of these mutants maintained their low-K+-tolerant phenotype in their M-3 generations, respectively. Genetic analysis showed that either one of these two mutants has a monogenic recessive mutation in a nuclear gene, and that the two mutations in two independent mutants are allelic to each other.
基金Supported by Introducing Talent Fund of Beijing University of Agricul-tural(9997116025)Elite Teaching Fund of Beijing Education Committee(PXM2007-014207-04453)Prominent Elite Fund of Beijing Education Committee(PXM2007-014207-044560)~~
文摘[Objective] M3 progenies of Jingnong 6 variety induced by EMS chemical mutagenesis were screened and identified for obtaining valuable mutation material.[Method] Azuki bean cultivar Jingnong 6 was treated with EMS.The mutation rate,mutation types,agronomic traits and yield components of the leaf mutants were analyzed.[Result] The results showed that there is the most abundant mutational type of leaf shape and the highest mutation frequency treated with 0.9% EMS for 24 hours.Comprehensive analysis on agronom...
基金Supported by the“973”Program(2003CB114204)the Science and Technology Plan(D0706005040431)~~
文摘[Objective] The research aimed to reveal the functions of NAC and UBA domains in Peatl＇s thermal stability. [Method] Fusion expression vectors of Pearl protein and the 3 deletion mutants were constructed. The recombinant plasmids were induced by IPTG and the target proteins （Peatl, Peatl-△CD99,Peatl-△ND49 and Pearl-△ND108 ）were expressed obtained by AKTA and its thermal stability was analyzed. [Result] The research found that 3 deletion mutants have good thermal stability like Pearl. [Conclusion] The research demonstrated that the coexistence of NAC or UBA domains is not necessary to thermal stability of Pearl protein , and they may give the protein particular stability structure seperately.
基金Supported by National Science and Technology Major Project of China,No.2012ZX10002007-001-002 and No.2013ZX10002001(to Zhang JM)the National Natural Science Foundation of China,No.81271833 and No.81471933(to Zhang JM)+1 种基金the Science and Technology Plan Project of Taizhou,Zhejiang province,No.1402ky19(to Tu WH and Hou W)the Scientific Research Project of Taizhou University,Zhejiang province,No:2014PY054(to Tu WH and Hou W)
文摘AIM:To investigate precore/basal core promoter(PC/BCP) mutants throughout hepatitis B virus(HBV) infection and to determine their relationship to hepatitis B early antigen(HBeA g) titers.METHODS:We enrolled 191 patients in various stages of HBV infection at the Huashan Hospital and the Taizhou Municipal Hospital from 2010 to 2012.None of the patients received antiviral therapy.HBV DNA from serum,was quantified by real-time PCR.The HBV genotype was determined by direct sequencing of the S gene.We used the Simpleprobe ultrasensitivequantitative method to detect PC/BCP mutants in each patient.We compared the strain number,percentage,and the changes in PC/BCP mutants in different phases,and analyzed the relationship between PC/BCP mutants and HBe Ag by multiple linear regression and logistic regression.RESULTS:Patients with HBV infection(n = 191) were assigned to groups by phase:Immune tolerance(IT) = 55,Immune clearance(IC) = 67,Low-replicative(LR) = 49,and HBeA g-negative hepatitis(ENH) = 20.Of the patients(male,112; female,79) enrolled,122 were HBe Ag-positive and 69 were HBe Ag-negative.The median age was 33 years(range:18-78 years).PC and BCP mutation detection rates were 84.82%(162/191) and 96.86%(185/191),respectively.In five HBe Ag-negative cases,we detected double mutation G1896A/G1899 A.The logarithm value of PC mutant quantities(log10 PC) significantly differed in IT,IC,and LR phases,as well as in the ENH phase(F = 49.350,P < 0.001).The logarithm value of BCP mutant quantities(log10 BCP) also differed during the four phases(F = 25.530,P < 0.001).Log10 PC and log10 BCP values were high in the IT and IC phases,decreased in the LR phase,and increased in the ENH phase,although the absolute value at this point remained lower than that in the IT and IC phases.PC mutant quantity per total viral load(PC%) and BCP mutant quantity per total viral load(BCP%) differed between phases(F = 20.040,P < 0.001; F = 10.830,P < 0.001),with PC% and BCP% gradually increasing in successive phases.HBeA g titers negatively correlated with PC%(Spearman's rho =-0.354,P < 0.001) and BCP%(Spearman's rho =-0.395,P < 0.001).The negative correlation between PC% and HBeA g status was significant(B =-5.281,P = 0.001),but there was no such correlation between BCP% and HBeA g status(B =-0.523,P = 0.552).CONCLUSION:PC/BCP mutants become predominant in a dynamic and continuous process.Log10 PC,log10 BCP,PC% and BCP% might be combined to evaluate disease progression.PC% determines HBeA g status.
基金supported by the National Key R&D Project of China (2018YFA0801000 and 2018YFD0901205)National Natural Science Foundation of China (Nos. 31721005, 31671501 and 31222052)+1 种基金the Youth Innovation Association of CASthe State Key Laboratory of Freshwater Ecology and Biotechnology (No. 2019FBZ05).
文摘The clustered regularly interspaced short palindromic repeats(CRISPR)/Cas9 technology has been widely utilized for knocking out genes involved in various biological processes in zebrafish. Despite this technology is efficient for generating different mutations, one of the main drawbacks is low survival rate during embryogenesis when knocking out some embryonic lethal genes. To overcome this problem, we developed a novel strategy using a combination of CRISPR/Cas9 mediated gene knockout with primordial germ cell(PGC) transplantation(PGCT) to facilitate and speed up the process of zebrafish mutant generation, particularly for embryonic lethal genes. Firstly, we optimized the procedure for CRISPR/Cas9 targeted PGCT by increasing the efficiencies of genome mutation in PGCs and induction of PGC fates in donor embryos for PGCT. Secondly, the optimized CRISPR/Cas9 targeted PGCT was utilized for generation of maternal-zygotic(MZ) mutants of tcf7l1a(gene essential for head development), pou5f3(gene essential for zygotic genome activation) and chd(gene essential for dorsal development) at F1 generation with relatively high efficiency. Finally, we revealed some novel phenotypes in MZ mutants of tcf7l1 a and chd, as MZtcf7l1 a showed elevated neural crest development while MZchd had much severer ventralization than its zygotic counterparts. Therefore, this study presents an efficient and powerful method for generating MZ mutants of embryonic lethal genes in zebrafish. It is also feasible to speed up the genome editing in commercial fishes by utilizing a similar approach by surrogate production of CRISPR/Cas9 targeted germ cells.
文摘Tissue culture has been widely used for mass propagation of Phalaenopsis. However, somaclonal variation occurred during micropropagation process posed a severe problem by affecting product quality. In this study, wild type and peloric flower buds of Phalaenopsis hybrids derived from flower stalk nodal culture were used for cDNA-RAPD and cDNA suppression subtractive hybridization analyses in order to study their genetic difference in terms of expressed sequence tags. A total of 209 ESTs from normal flower buds and 230 from mutants were sequenced. These ESTs sequences can be grouped into several functional categories involved in different cellular processes including metabolism, signal transduction, transcription, cell growth and division, protein synthesis, and protein localization, and into a subcat- egory of proteins with unknown function. Cymbidium mosaic virus transcript was surprisingly found expressed fre- quently in the peloric mutant of P. Little Mary. Real-time RT-PCR analysis on selected ESTs showed that in mutant flower buds, a bZIP transcription factor (TGA1a-like protein) was down-regulated, while up-regulated genes include auxin-regulated protein kinase, cyclophilin, and TCP-like genes. A retroelement clone was also preferentially expressed in the peloric mutant flowers. On the other hand, ESTs involved in DNA methylation, chromatin remodeling and post- transcriptional regulation, such as DNA methyltransferase, histone acetyltransferase, ERECTA, and DEAD/DEAH RNA helicase, were enriched in normal flower buds than the mutants. The enriched transcripts in the wild type indicate the down regulation of these transcripts in the mutants, and vice versa. The potential roles of the analyzed transcripts in the development of Phalaenopsis flowers are discussed.
基金supported by the National Funds for Distinguished Young Scientists in China(Grant No.31025003) to Y.Guo
文摘It is established that different stresses cause signal-specific changes in cellular Ca2 ~ level, which function as messengers in modulating diverse physiological processes. These calcium signals are important for stress adaptation. Though numbers of downstream components of calcium signal cascades have been identified, upstream events in calcium signal remain elusive, specifically components required l＇~~r calcium signal generation due to the lack of high-throughput genetic assay. Here, we report the development of an easy and efficient method in a forward genetic screen for Ca2＋ signals-deficient mutants in Arahidopsis thaliana. Using this method, 121 mutants with disordered NaCI- and H=O2-induced Ca2＋ signals are isolated.
基金supported by the 12th Five-year Plan of Bayberry Special Breeding,Zhejiang Province,China(2012C12904-3.2)Taizhou Science and Technology Bureau,China(2013A22010)
文摘In this study, two ploidy mutant lines ofMyrica rubra cv. Dongkui （DK） were identiifed and named as DB1 and DB2. The lforal organ, leaf cel structure, ploidy, and number of chromosomes of the two mutants were investigated. Meanwhile, anthocyanin contents at different developmental stages were analyzed, and the Cy-3-glu contents of DB1 and DB2 at the ful ripe stages are signiifcantly higher than that of DK by 27.84 and 23.51%, respectively. Furthermore, 6 RNA libraries at two developmental stages （young fruit stage and ful ripe stage） were built for RNA-Seq. By mapping to the reference database, 28407, 28043, and 28683 genes were detected in the young fruit of DB1, DB2, and DK, respectively, while 28040, 22256, and 27351 genes were detected in the ful ripe stage, respectively. There were 281 differentialy expressed genes between DB1 and DK, with 123 and 158 genes up-regulated and down-regulated, respectively, and 47 differentialy expressed genes between DB2 and DK, of which 8 and 39 genes were up-regulated and down-regulated. Using real-time PCR, the expression levels of the eight functional genes at different developmental stages of the fruit were also analyzed. These comprehensive analyses showed that both mutants are different from DK, which is the result of natural doubling of ploidy, thereby generating a pleiotropic effect. As we known, it is the ifrst report to study the relationship between bayberry ploidy alterations and genes involved in regulation of fruit mutations, which wil help to identify the morphological and cytological characteristics ofM. rubragermplasm, and provide a theoretical basis and technical support for genetic improvement and creation of breeding resources.
基金supported by the National Key Research and Development Program of China(2016YFD0100101)the 948 Program of China(2006-G51)the European Commission within the 6th Framework Program(ECFP6)INCO-2003-B1.2(CEDROME-015468)
文摘The two mutants idr1-1 and 297-28, which were obtained from the radiation mutation of HD297 and IAPAR9, were used as experimental materials in this study for a 2-year(2012 and 2013) experiment about field drought resistance identification in Beijing, China. Key agronomic traits and water-related physiological indexes were observed and measured, including the leaf anti-dead level(LADL), days to heading, plant height, setting percentage, aboveground biomass, leaf water potential(LWP), net photosynthetic rate(Pn) and transpiration rate. The results showed that the mutant idr1-1 that was under drought stress(DS) conditions for 2 years had the highest LADL grades(1.3 and 2.0) among all the materials, and they were 2–3 grades stronger than the wild-type IAPAR9 with an average that was 21.4% higher for the setting percentage than the wild type. Compared with the IAPAR9 for the 2-year average delay in the days to heading and the reduction rates in the plant height, setting percentage, and aboveground biomass under DS compared with the well-watered(WW) treatment, idr1-1 showed 3.2% less delay and 19.1, 16.4, and 6.1% less reduction, respectively. The idr1-1 in the LWP always exhibited the highest performance among all the materials. The Pn of idr1-1 under severe and mild DS comparing with that under WW was slightly decreased and even slightly increased, respectively, leading to an average reduction rate of only 0.92%, which was 26.93% less than that of IAPAR9. Under the severe DS, idr1-1 still showed the highest value of 16.88 μmol CO2 m–2 s–1 among all the materials and was significantly higher than that of IAPAR9(11.66 μmol CO2 m–2 s–1). Furthermore, only idr1-1 had the increased and the highest transpiration rate values(7.6 and 6.04 mmol H2 O m–2 s–1) under both mild and severe DS compared with the values under WW, when the transpiration rate of all the other materials significantly decreased. By contrast, the 297-28 in terms of the LADL grade under DS was the lowest(7.0), and it was four grades weaker than its wildtype HD297 and even one grade weaker than the drought-sensitive paddy rice SN265. For the 2-year average reduction rates in aboveground biomass and plant heights under DS compared with those under the WW, 297-28 was 31.6 and 31.8% higher than HD297, respectively. Meanwhile, 297-28 showed the worst performance for the LWP, Pn, and transpiration rate. These results suggest that idr1-1 might be a superior drought tolerant mutant of upland rice found in China. It has a strong ability to maintain and even enhance leaf transpiration while maintaining a high plant water potential under DS, thus supporting a high Pn and alleviating the delay in agronomic trait development and yield loss effectively. 297-28 is a much more highly drought-sensitive mutant that is even more sensitive than paddy rice varieties. The two mutants could be used as drought tolerance controls for rice germplasm identification and the drought resistant mechanism studies in the future. idr1-1 is also suitable for breeding drought-tolerant and lodging-resistant high-yield rice varieties.
基金financially supported by the Innovation Program and Youth elite Program of Chinese Academy of Agricultural Sciencesthe Special Fund for Agro-scientific Research in the Public Interest of China(201503114)
文摘The resistance of soybean(Glycine max(L.) Merr.) to soybean cyst nematode(SCN, Heterodera glycines Ichinohe), which is a devastating pathogen in soybean production and causes a large quantity of annual yield loss worldwide, can shift during the long-term interaction and domestication. It is vital to identify more new resistance genetic sources for identification of novel genes underlying resistance to SCN for management of this pathogen. In the present study, first, two ethane methylsulfonate-mutagenesis soybean M2 populations of PI 437654, which shows a broad resistance to almost all of SCN races, and Zhonghuang 13, which is a soybean cultivar in China conferring strong resistance to lodging, were developed. Many types of morphological phenotypes such as four-and five-leaflet leaves were observed from these two soybean M2 populations. Second, 13 mutants were identified and confirmed to exhibit alteration of resistance to SCN race 4 through the forward genetic screening of 400 mutants of the PI 437654 M2 population, the rate of mutants with alteration of SCNinfection phenotype is 3.25%. Third, these identified mutants were further verified not to show any changes in the genomic sequences of the three known SCN-resistant genes, GmSHMT08, GmSNAP18 and GmSANP11, compared to the wildtype soybean; and all of them were still resistant to SCN race 3 similar to the wild-type soybean. Taken together, we can conclude that the 13 mutants identified in the present study carry the mutations of the new gene(s) which contribute(s) to the resistance to SCN race 4 in PI 437654 and can be potentially used as the genetic soybean sources to further identify the novel SCN-resistant gene(s).
文摘AIM： To conduct a retrospective study in 400 chronic hepatitis B patients in order to identify hepatitis B viral factors associated with complications of liver disease or development of hepatocellular carcinoma. METHODS： The mean follow-up time was 83.6 ± 39.6 mo. Alpha-fetoprotein test and abdominal ultrasound were used for cancer surveillance. Hepatitis B basal core promoter mutants, precore mutants, genotypes, hepatitis B viral DNA （HBV DNA） level and hepatitis B e antigen （HBeAg） were measured. Univariate analysis and logistic regression were used to assess odds ratios for viral factors related to liver deaths and hepatocellular carcinoma development. RESULTS： During follow-up, 38 patients had liver deaths not related to hepatocellular carcinoma. On multivariate analysis, older age [odds ratio： 95.74 （12.13-891.31）, P 〈 0.0001], male sex [odds ratio： 7.61 （2.20-47.95）; P = 0.006], and higher Iogzo HBV DNA [odds ratio： 4.69 （1.16-20.43）; P 〈 0.0001] were independently predictive for these liver related deaths. Also, 31 patients developed hepatocellular carcinoma. Multivariate analysis showed that older age [odds ratio： 26.51 （2.36-381.47）; P = 0.007], presence of precore mutants [odds ratio： 4.23 （1.53-19.58）, P = 0.02] and presence of basal core promoter mutants [odds ratio： 2.93 （1.24-7.57）; P = 0.02] were independent predictors for progression to hepatocellular carcinoma. CONCLUSION： Our results show that high levels of baseline serum HBV DNA are associated with non- hepatocellular carcinoma-related deaths of liver failure, while genetic mutations in the basal core promoter and precore regions are predictive for development of hepatocellular carcinoma.
