Rice false smut(RFS),caused by the ascomycete fungus Ustilaginoidea virens(Cooke)Takahashi,is a notable panicle disease of rice.Mycoviruses represent a category of viruses capable of infecting various fungal groups,ga...Rice false smut(RFS),caused by the ascomycete fungus Ustilaginoidea virens(Cooke)Takahashi,is a notable panicle disease of rice.Mycoviruses represent a category of viruses capable of infecting various fungal groups,garnering interest for their potential application in the biological control of plant fungal diseases.We identified a novel positive-sense single-stranded RNA virus,named Ustilaginoidea virens mitovirus 1(UvMV1),from an abnormal U.virens strain Uv488.The complete genome sequence of UvMV1 is 2474 nt in length and contains a large open reading frame encoding RNA-dependent RNA polymerase.UvMV1 is classified as a new member of the genus Unuamitovirus in the family Mitoviridae based on phylogenetic analysis.It is effectively transmitted vertically through conidia of strain Uv488 and horizontally through hyphal fusion between vegetatively compatible individuals with an 80%transmission efficiency.We further demonstrated that UvMV1 significantly influenced conidiation,colony morphology,growth rate,secondary metabolite production,and the response to environmental stress in U.virens.Furthermore,qRT-PCR results aimed at detecting the expression levels of autophagy-related genes suggested that UvMV1 infection had the potential to induce autophagy in U.virens.Activation or inhibition of autophagy through chemical experiments demonstrated that UvMV1 enhances viral titers by inducing autophagy in U.virens,while inhibition of autophagy results in decreased UvMV1 titers.Transcriptome analyses consistently demonstrated that UvMV1 regulated the expression of genes associated with secondary metabolism,mycelial growth,virulence,and the mitogen-activated protein kinase signaling pathway,thereby influencing both the antiviral response and the virulence of U.virens.The data presented collectively identified a novel mycovirus responsible for inducing growth abnormalities in U.virens,and elucidated the regulatory mechanisms during mycovirus-host fungus interactions,particularly the autophagy pathway.These findings offer new perspectives and potential control strategies for managing RFS in agricultural settings.展开更多
Photosynthesis is the basis of crop growth and is sensitive to stress.Smut(Sporisorium destruens)is the primary disease in the production of broomcorn millet(Panicum miliaceum L.).This study evaluated the effects of i...Photosynthesis is the basis of crop growth and is sensitive to stress.Smut(Sporisorium destruens)is the primary disease in the production of broomcorn millet(Panicum miliaceum L.).This study evaluated the effects of infection with S.destruens on the photosynthesis of the resistant cultivar(BM)and susceptible cultivar(NF).After inoculation,there was a decrease in the chlorophyll content,gas exchange parameters,and chlorophyll fluorescence of the two cultivars.Observation of the ultrastructure of diseased leaves showed that the chloroplasts and mitochondria had abnormal morphology,and some vacuoles appeared.RNA-seq was performed on the flag leaves after inoculation.In addition to the resistant and susceptible cultivars,the diseased leaves developed from inflorescences were defined as S2.The analysis showed that the pathways related to photosynthesis stimulated some differentially expressed genes(DEGs)after infection with S.destruens.More DEGs were induced in the susceptible broomcorn millet NF than in the resistant broomcorn millet BM,and most of those genes were downregulated.The number of DEGs induced by S2 was greater than that in susceptible cultivar NF,and most of them were upregulated.These results indicate that infection with S.destruens affects the normal photosynthetic performance of broomcorn millet.Understanding the mechanism between S.destruens,photosynthesis,and broomcorn millet is an effective measure to prevent the occurrence of smut and enhance its resistance.展开更多
Flower-infecting fungi have caused many economically important diseases in crop production.The fungal pathogen Ustilaginoidea virens infects developing rice florets,causing false smut disease,which leads to reduced gr...Flower-infecting fungi have caused many economically important diseases in crop production.The fungal pathogen Ustilaginoidea virens infects developing rice florets,causing false smut disease,which leads to reduced grain yield and quality,as well as contamination with mycotoxins that pose hazards to human health and food security.To ensure rice production,substantial efforts have been made to understand the interaction between rice and U.virens.In this review,we summarize the current understanding of rice resistance mechanisms to U.virens.We discuss the evaluation of false smut resistance,quantitative resistance loci,potential defense strategies of rice panicles,pathogen effector-driven identification of resistance-related genes,and engineering of false smut resistance.We conclude by proposing an integrated defense system that includes disease avoidance,immune response,metabolic adaptation,and the inhibition of susceptibility factors.Furthermore,we outline four critical stages of interaction between rice and U.virens that are essential for understanding and enhancing organ-specific rice resistance to false smut disease.展开更多
A recombinant inbred line （RILs） population with 157 lines derived from an inter-subspecies cross of Daguandao （japonica）/IR28 （indica） by the single seed de-scent method was used to detect quantitative trait lo...A recombinant inbred line （RILs） population with 157 lines derived from an inter-subspecies cross of Daguandao （japonica）/IR28 （indica） by the single seed de-scent method was used to detect quantitative trait loci （QTLs） conferring resistance to rice false smut caused by Ustilaginoidea virens（Cooke） Takahashi in Nanjing and Yangzhou. The disease rate index of the two parents and 157 RILs caused by rice false smut were scored and the QTLs for rice false smut resistance were detected accordingly by QTL Cartographer software. Eight QTLs control ing false smut resis-tance were detected on chromosomes 1, 2, 4, 8, 10, 11 and 12, respectively, with the phenotypic variance of 8.6%-22.5%. There were five QTLs detected in Nanjing and Yangzhou, respectively, and only two QTLs were found in both two years, the phenotypic variation was explained by individual QTL ranged from 18.0% to 18.9% for these two QTLs, and the additive effects of these two QTLs contributed to the 8.0%-14.6% decrease of disease index and therefore the disease resistance increased. The direction of the additive effects at six loci qFsr1, qFsr2, qFsr8, qFsr10a, qFsr11 and qFsr12 coincided with that predicted by phenotypes of the parents, and the IR28 al eles at these loci had positive effect against rice false smut while the negative effects were found in Daguandao al eles at qFsr4 and qFsr10b. Both qFsr10a and qFsr11 should be useful in rice breeding for resistance to rice false smut in marker-assisted selection （MAS） program.展开更多
[Objective] This study aims to screen for the high effective fungicides which could significantly decrease the disease incidence and disease index of rice false smut. [Method] The inhibitory activities of the fungicid...[Objective] This study aims to screen for the high effective fungicides which could significantly decrease the disease incidence and disease index of rice false smut. [Method] The inhibitory activities of the fungicide against mycelial growth of Ustilaginoidea virens were measured to in vitro evaluate the ECho values. And 17 fungicides were sprayed to evaluate the efficacy and effect of the fungicides tested in the field trials on the rice characters, [Result] The results showed that epoxicona- zole, difenoconazole, propiconazole and procloraz exhibited high inhibitory activity against mycelial growth of Ustilaginoidea virens with the ECso values 0.04, 0.07, 0.12 and 0.11 pg/ml, respectively. The results of field trials showed that the efficacy of Wen- quning, and fungicides such as difenoconazole, prochloraz, propiconazole, epoxi- conazole and their mixtures in controlling rice false smut were all 70% or more. [Conclusion] The 17 tested fungicides behaved efficacy in controlling rice false smut and did not cause drug injury on leaves and grains of rice plants, sprayed when flag leaves of rice fully expanded.展开更多
[ Objective ] The paper was to establish the near isogenic lines of Huangzaosi maize with resistance against maize head smut, and to provide basis for its wide application in breeding and production. [Method] Combing ...[ Objective ] The paper was to establish the near isogenic lines of Huangzaosi maize with resistance against maize head smut, and to provide basis for its wide application in breeding and production. [Method] Combing with hybrid, backcress and self-cross method, as well as molecular markers, Huangzaosi maize was successfully introduced with head smut resistance, and its near isogenic lines were studied. The characteristics of resistant and susceptible variation and the changes of combining ability of near isogenic lines after backcrossing breeding were observed. [ Result ] The incidence rate of Huangzansi maize in control was 46% ; the incidence rates of the selected 24 near isogenic lines of resistant Huangzaosi were all lower than 10%, and the selected rate was 92.6% ; the combining ability of most near isogenic lines of resistant Huangzaosi maize had no significant difference with that of H^i maize in control; the yields of hybrids prepared by several inbred lines such as M135 and M140 were outstanding, which exceeded the control Zhengdan 958, showing a higher combining ability. [ Conclusion] The phenotype and combining ability of near isngenic lines of Huangzaosi maize with resistance against maize head smut obtained in the test were very close to Huan- gzaosi, and its resistance against maize head smut was greatly increased, thus solving the problems of Huangzaesi without resistance against maize head smut.展开更多
In order to identify the resistant gene of rice false smut in rice, a recombi- nant inbred line （RILs） population with 157 lines derived from an inter-subspecies cross of Daguandao/IR28 by the single seed descent me...In order to identify the resistant gene of rice false smut in rice, a recombi- nant inbred line （RILs） population with 157 lines derived from an inter-subspecies cross of Daguandao/IR28 by the single seed descent method was used to detect quantitative trait loci （QTLs） conferring resistance to strain Pi-1 of rice false smut caused by Usti/aginoiclea virens （Cooke） Takahashi in 2012 and 2013. The disease rate indexes of the two parents and 157 RILs caused by the strain Pi-1 of rice false smut were scored and the QTLs for rice false smut resistance were detected accordingly by QTL Cartographer software. Seven QTLs controlling false smut re- sistance were detected on chromosomes 2, 7, 8, 11 and 12, respectively, with the phenotypic variance of 8.5%-17.2%. There were four QTLs detected in 2012 and 2013, respectively, and only one QTL was found in both two years, the phenotypic variation explained by this individual QTL was 13.5% and 17.2%, and the additive effects of this QTL contributed to the 9.9% and 14.3% decrease of disease index and therefore the disease resistance increased. The direction of the additive effects at five loci qFsr2a, qFsr8a, qFsr8b, qFsr11 and qFsr12 coincided with that predicted by phenotypes of the parents, and the IR28 alleles at these loci had positive effect against rice false smut while the negative effects were found in Daguandao alleles at qFsr2b and qFsr7. The qFsr11 should be useful in rice breeding for resistance to rice false smut in marker-assisted selection （MAS） program.展开更多
In order to test the control effect of 6% tebuconazole FS on maize head smut and to select its optimal dose for mixing seed, field tests were performed in 2012 and 2013. The results showed that 6% tebuconazole FS was ...In order to test the control effect of 6% tebuconazole FS on maize head smut and to select its optimal dose for mixing seed, field tests were performed in 2012 and 2013. The results showed that 6% tebuconazole FS was effective to control maize head smut, and the control effect ranged from 73.4% to 91.1%. In addition, it also improved the maize yield by 36.7%-44.1%, compared with the blank control. The optimal dose of 6% tebuconazole FS for seed dressing was 166.5 g/100 kg to control head smut on maize.展开更多
Rice false smut disease, which is caused by the fungus Ustilaginoidea virens, is currently one of the most devastating rice fungal diseases in the world. Rice false smut disease not only causes severe yield loss and g...Rice false smut disease, which is caused by the fungus Ustilaginoidea virens, is currently one of the most devastating rice fungal diseases in the world. Rice false smut disease not only causes severe yield loss and grain quality reduction, but also threatens food safety due to its production of mycotoxins. In this review, the most recent progresses regarding the life cycle, infection processes, genome and genetic diversity, pathogenic gene and disease resistance in rice were summarized in order to provide theoretical basis for the control of U. virens. We also proposed some future directions and key questions that need to be addressed for a better understanding of the molecular mechanism that leads to rice false smut disease and the prospects for sustainable control of rice false smut.展开更多
The sclerotia of Villosiclava virens were found commonly in high altitude and the temperate regions, where the temperatures are relatively low in rice filling stage. To make sure if low temperature induce the scleroti...The sclerotia of Villosiclava virens were found commonly in high altitude and the temperate regions, where the temperatures are relatively low in rice filling stage. To make sure if low temperature induce the sclerotial formation in V. virens, the inoculated rice panicles in laboratory and the diseased rice panicles cut from paddy fields were treated under different temperatures. The results showed that 3 days of night temperature at 15°C were enough to induce the sclerotial formation. The low temperature was much more effective for young balls with intact membranes. After appearance of chlamydospores on the ball surfaces, the sclerotium could not differentiate anymore. The sclerotia began to differentiate below the chlamydospore layer and gradually grew onto the ball surfaces. This suggests that low temperature in the early development stage of false smut balls is an important factor to induce the sclerotial differentiation, and rice cultivars with long growth periods are able to produce more sclerotium-bearing balls, which will produce mass of spores in paddy field in the coming year.展开更多
Rice false smut disease is an increasing concern for research and production, not only because of the increasing epidemic occurrence in rice production, but also the intriguing specific pathogenesis of the disease to ...Rice false smut disease is an increasing concern for research and production, not only because of the increasing epidemic occurrence in rice production, but also the intriguing specific pathogenesis of the disease to be a unique pathological system to enrich the molecular mechanism of plant-microbe interaction. Progresses have been achieved in the pathogen phylogenetic placement, the alternative hosts, the pathogen morphology and diversity, the toxins generated by false smut balls, the artificial inoculation method, and the pathogen transformation as well as rice resistance to the disease. However, it is still controversy on the infection process. It is not clear how the life cycle of this pathogen is coupled with the disease cycle. This review summarized our current understanding on the pathogen, the pathogenesis, and the rice resistance to the disease. Future work should pay attention to developing a more rapid and effective system to evaluate rice resistance and susceptibility to the disease, screening of rice germplasm for disease-resistance breeding, studying the resistance inheritance, and investigating the molecular mechanism of rice-false smut fungus interaction.展开更多
Ustilago coicis causes serious smut on Coix lacryma-jobi in Dayang Town,Jinyun County,Zhejiang Province of China.In this paper,ultrastructural assessments on fungus-host interactions and teliospore development are pre...Ustilago coicis causes serious smut on Coix lacryma-jobi in Dayang Town,Jinyun County,Zhejiang Province of China.In this paper,ultrastructural assessments on fungus-host interactions and teliospore development are presented,and molecular phylogenetic analyses have been done to elucidate the phylogenetic placement of the taxon.Hyphal growth within infected tissues was both intracellular and intercellular and on the surface of fungus-host interaction,and the fungal cell wall and the invaginated host plasma membrane were separated by a sheath comprising two distinct layers between the fungal cell wall and the invaginated host plasma membrane.Ornamentation development of teliospore walls was unique as they appeared to be originated from the exosporium.In addition,internal transcribed spacer(ITS) and large subunit(LSU) sequence data showed that U.coicis is closely related to Ustilago trichophora which infects grass species of the genus Echinochloa(Poaceae).展开更多
Ustilaginoidea virens is a flower-infecting fungus that forms false smut balls in rice panicle. Rice false smut has long been considered a minor disease, but recently it occurred frequently and emerged as a major dise...Ustilaginoidea virens is a flower-infecting fungus that forms false smut balls in rice panicle. Rice false smut has long been considered a minor disease, but recently it occurred frequently and emerged as a major disease in rice production. In vitro co-cultivation of U. virens strain with young rice panicles showed that U. virens enters inside of spikelets from the apex and then grows downward to infect floral organs. In response to U. virens infection, rice host exhibits elevated ROS accumulation and enhanced callose deposition. The secreted compounds of U. virens can suppress rice pollen germination. Examination of sectioning slides of freshly collected smut balls demonstrated that both pistil and stamens of rice flower are infected by U. virens, hyphae degraded the contents of the pollen cells, and also invaded the filaments. In addition, U. virens entered rice ovary through the thin-walled papillary cells of the stigma, then decomposed the integuments and infected the ovary. The invaded pathogen could not penetrate the epidermis and other layers of the ovary. Transverse section of the pedicel just below the smut balls showed that there were no fungal hyphae observed in the vascular bundles of the pedicel, implicating that U. virens is not a systemic flower-infecting fungus.展开更多
Smut is a serious disease in Job's tears,also known as adlay,and contributes to the reduction of crop yield in agricultural fields.In this study,the key pathogenic fungi in adlay smut disease were first identified...Smut is a serious disease in Job's tears,also known as adlay,and contributes to the reduction of crop yield in agricultural fields.In this study,the key pathogenic fungi in adlay smut disease were first identified by internal transcribed spacer region(ITS)high-throughput sequencing and then used to elucidate the composition and diversity of the fungal community in adlay smut.Results indicate that an abundance of operational taxonomic units(OTUs)were detected in the infected involucres of flowering plants and the OTUs were classified to nine phyla,20 classes,45 orders,90 families and 119 genera.A total of 4986 OTUs clustered together,sharing six core OTUs in all samples,while 145 OTUs were shared among four geographical groups.The Shannon and Simpson indices ranged from 0.137–1.629 and 0.357–0.970,respectively.Community diversity ranked as Anshun(AS)>Qinglong(QL)>Xingren(XR)>Xingyi(XY)among the four geographical groups by Shannon and Simpson indices,exhibiting complex community diversities among accessions and geographical groups.The richness and diversity data imply a weak relationship between the accession community richness and geographical origins of samples.Two closely related fungal genera,Sporisorium and Ustilago,were implicated as causes of smut disease.The genus Sporisorium appears to be more commonly found among accessions and thus is more likely to be the fungal pathogen causing smut in adlay.This work can facilitate strategies to control and prevent smut infection to improve adlay yield.展开更多
Ustilaginoidea virens is the causal agent of rice false smut,which can be a highly destructive disease of rice.The plasma membrane phosphatase Psr1 proteins,which act as a regulator of the salinity stress response in ...Ustilaginoidea virens is the causal agent of rice false smut,which can be a highly destructive disease of rice.The plasma membrane phosphatase Psr1 proteins,which act as a regulator of the salinity stress response in yeast,are widely distributed across fungi,but their functional characterization is sketchy.In this study,we characterized the functions of Psr1 protein,UvPsr1,in U.virens.Analyses of the AUvpsr1 and its complementation strain showed that UvPsr1 is required for normal mycelial growth,conidiation and tolerance to oxidative,osmotic and cell wall stresses.When rice panicles were inoculated with the AUvpsr1 strains,no symptoms of false smut disease developed,showing that UvPSR1 also contributes to the pathogenicity of the fungus.The deletion mutant of UvPSR1 also appeared to produce a smaller titer of toxic compounds able to inhibit elongation of the germinated seeds.In conclusion,our results indicated that UvPsr1 is a new pathogenic factor of U.virens.展开更多
Head smut, caused by the fungal pathogen Sporisorium reilianum, poses a grave threat to maize(Zea mays) production worldwide. Here we report cytological and molecular evidence for maize resistance to head smut. During...Head smut, caused by the fungal pathogen Sporisorium reilianum, poses a grave threat to maize(Zea mays) production worldwide. Here we report cytological and molecular evidence for maize resistance to head smut. During early stages of root infection, S. reilianum mycelium was capable of penetrating the root epidermis of both resistant(Ji1037) and susceptible(HZ4) inbred lines. S. reilianum hyphae were observed in the root–stem junction at 6 days after inoculation. In an attempt to monitor hyphal spread within the maize plant,a highly specific and sensitive real-time PCR method was established to estimate the hyphal content in infected maize tissues. During the upward growth of endophytic S.reilianum, the extent of hyphal spread was markedly different between Ji1037 and HZ4. Very little or no pathogen was detected in aerial parts of Ji1037, whereas large amounts of pathogen accumulated in aboveground tissues, particularly inflorescences, of HZ4. Thus,maize resistance to S. reilianum was achieved mainly by inhibition of endophytic hyphal growth rather than by prevention of early-root penetration by the pathogen.展开更多
[Objective] The aim of this study was to explore the inheritance pattern of the resistance of two-line hybrid rice to false smut. [Method] A moderate susceptible TGMS line 33S as the female parent, was crossed with 30...[Objective] The aim of this study was to explore the inheritance pattern of the resistance of two-line hybrid rice to false smut. [Method] A moderate susceptible TGMS line 33S as the female parent, was crossed with 30 susceptible restorer lines and 23 resistant restorer lines. Then false smut resistance of the hybrid F1 and parents were identified. [Result] All F1 of 33S crossed with 30 susceptible re- storer lines were susceptible to rice false smut. The F1 of 33S crossed with 23 re- sistant restorer lines showed dominant, incompletely dominant or recessive inheri- tance. Dominant and incompletely dominant inheritance accounted for 87.0%. The diseased panicle rate, disease index, average diseased grains per panicle, and the highest diseased grains per panicle of F1 shared highly significant positive correla- tions with corresponding indicators of restorer lines. [Conclusion] This study provides references for genetic improvement of two-line hybrid rice.展开更多
Some stress response-related genes have been identified in Ustilaginoidea virens,but it is not clear whether and how defects of stress responses affect the pathogenesis processes of U.virens.In this study,we identifie...Some stress response-related genes have been identified in Ustilaginoidea virens,but it is not clear whether and how defects of stress responses affect the pathogenesis processes of U.virens.In this study,we identified a general stress response factor UvWHI2 as a homolog of Saccharomyces cerevisiae Whi2 in U.virens.The relative expression level of Uv Whi2 was significantly up-regulated during infection,suggesting that UvWHI2 may be involved in pathogenesis.Furthermore,knockout of Uv Whi2 showed decreased mycelial growth,increased conidiation in the potato sucrose medium and a defect in pathogenicity.In addition,the RNA-Seq and phenotypic analysis showed that UvWHI2 was involved in response to oxidative,hyperosmotic,cell wall stress and nutrient limitation.Further studies revealed that the defects of stress responses of the?Uvwhi2 mutant affected the formation of secondary spores on the nutrient limited surface and the rice surface,resulting in a significant reduction of pathogenicity of U.virens.Our results suggest that UvWHI2 is necessary for fungal growth,stress responses and the formation of secondary spores in U.virens.In addition,the defects of stress responses can affect the formation of secondary spores on the rice surface,and then compromise the pathogenicity of U.virens.展开更多
Ustilaginoidea virens is a common rice pathogen that can easily lead to a decline in rice quality and the production of toxins pose potential risks to human health.In this review,we present a comprehensive literature ...Ustilaginoidea virens is a common rice pathogen that can easily lead to a decline in rice quality and the production of toxins pose potential risks to human health.In this review,we present a comprehensive literature review of research since the discovery of rice false smut.We provide a comprehensive and,at times,critical overview of the main results and findings from related research,and propose future research directions.Firstly,we delve into the interaction between U.virens and rice,including the regulation of transcription factors,the process of U.virens infecting rice panicles,and the plant immune response caused by rice infection.Following that,we discuss the identification and characterization of mycotoxins produced by the pathogenic fungus,as well as strategies for disease management.We emphasize the importance of comprehensive agricultural prevention and control methods for the sustainable management of U.virens.This knowledge will update our understanding of the interaction between U.virens and rice plants,offering a valuable perspective for those interested in U.virens.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.32072363 and 32360648).
文摘Rice false smut(RFS),caused by the ascomycete fungus Ustilaginoidea virens(Cooke)Takahashi,is a notable panicle disease of rice.Mycoviruses represent a category of viruses capable of infecting various fungal groups,garnering interest for their potential application in the biological control of plant fungal diseases.We identified a novel positive-sense single-stranded RNA virus,named Ustilaginoidea virens mitovirus 1(UvMV1),from an abnormal U.virens strain Uv488.The complete genome sequence of UvMV1 is 2474 nt in length and contains a large open reading frame encoding RNA-dependent RNA polymerase.UvMV1 is classified as a new member of the genus Unuamitovirus in the family Mitoviridae based on phylogenetic analysis.It is effectively transmitted vertically through conidia of strain Uv488 and horizontally through hyphal fusion between vegetatively compatible individuals with an 80%transmission efficiency.We further demonstrated that UvMV1 significantly influenced conidiation,colony morphology,growth rate,secondary metabolite production,and the response to environmental stress in U.virens.Furthermore,qRT-PCR results aimed at detecting the expression levels of autophagy-related genes suggested that UvMV1 infection had the potential to induce autophagy in U.virens.Activation or inhibition of autophagy through chemical experiments demonstrated that UvMV1 enhances viral titers by inducing autophagy in U.virens,while inhibition of autophagy results in decreased UvMV1 titers.Transcriptome analyses consistently demonstrated that UvMV1 regulated the expression of genes associated with secondary metabolism,mycelial growth,virulence,and the mitogen-activated protein kinase signaling pathway,thereby influencing both the antiviral response and the virulence of U.virens.The data presented collectively identified a novel mycovirus responsible for inducing growth abnormalities in U.virens,and elucidated the regulatory mechanisms during mycovirus-host fungus interactions,particularly the autophagy pathway.These findings offer new perspectives and potential control strategies for managing RFS in agricultural settings.
基金supported by the China Agriculture Research System of MOF and MARA(CARS-06-A26)the“Two-chain”Fusion Crop Breeding Key Project of Shaanxi,China(2021-LLRH-07)。
文摘Photosynthesis is the basis of crop growth and is sensitive to stress.Smut(Sporisorium destruens)is the primary disease in the production of broomcorn millet(Panicum miliaceum L.).This study evaluated the effects of infection with S.destruens on the photosynthesis of the resistant cultivar(BM)and susceptible cultivar(NF).After inoculation,there was a decrease in the chlorophyll content,gas exchange parameters,and chlorophyll fluorescence of the two cultivars.Observation of the ultrastructure of diseased leaves showed that the chloroplasts and mitochondria had abnormal morphology,and some vacuoles appeared.RNA-seq was performed on the flag leaves after inoculation.In addition to the resistant and susceptible cultivars,the diseased leaves developed from inflorescences were defined as S2.The analysis showed that the pathways related to photosynthesis stimulated some differentially expressed genes(DEGs)after infection with S.destruens.More DEGs were induced in the susceptible broomcorn millet NF than in the resistant broomcorn millet BM,and most of those genes were downregulated.The number of DEGs induced by S2 was greater than that in susceptible cultivar NF,and most of them were upregulated.These results indicate that infection with S.destruens affects the normal photosynthetic performance of broomcorn millet.Understanding the mechanism between S.destruens,photosynthesis,and broomcorn millet is an effective measure to prevent the occurrence of smut and enhance its resistance.
基金supported by grants from the Sichuan Natural Science Foundation(2024NSFSC0335 and SCCXTD-2024-SD-4 to D.-Q.L.)the National Natural Science Foundation of China(32372490 and 32072503 to J.F.)。
文摘Flower-infecting fungi have caused many economically important diseases in crop production.The fungal pathogen Ustilaginoidea virens infects developing rice florets,causing false smut disease,which leads to reduced grain yield and quality,as well as contamination with mycotoxins that pose hazards to human health and food security.To ensure rice production,substantial efforts have been made to understand the interaction between rice and U.virens.In this review,we summarize the current understanding of rice resistance mechanisms to U.virens.We discuss the evaluation of false smut resistance,quantitative resistance loci,potential defense strategies of rice panicles,pathogen effector-driven identification of resistance-related genes,and engineering of false smut resistance.We conclude by proposing an integrated defense system that includes disease avoidance,immune response,metabolic adaptation,and the inhibition of susceptibility factors.Furthermore,we outline four critical stages of interaction between rice and U.virens that are essential for understanding and enhancing organ-specific rice resistance to false smut disease.
基金Supported by the National Natural Science Foundation of China(31071397)the Fund for Independent Innovation of Agricultural Sciences in Jiangsu Province(CX(12)1003)~~
文摘A recombinant inbred line （RILs） population with 157 lines derived from an inter-subspecies cross of Daguandao （japonica）/IR28 （indica） by the single seed de-scent method was used to detect quantitative trait loci （QTLs） conferring resistance to rice false smut caused by Ustilaginoidea virens（Cooke） Takahashi in Nanjing and Yangzhou. The disease rate index of the two parents and 157 RILs caused by rice false smut were scored and the QTLs for rice false smut resistance were detected accordingly by QTL Cartographer software. Eight QTLs control ing false smut resis-tance were detected on chromosomes 1, 2, 4, 8, 10, 11 and 12, respectively, with the phenotypic variance of 8.6%-22.5%. There were five QTLs detected in Nanjing and Yangzhou, respectively, and only two QTLs were found in both two years, the phenotypic variation was explained by individual QTL ranged from 18.0% to 18.9% for these two QTLs, and the additive effects of these two QTLs contributed to the 8.0%-14.6% decrease of disease index and therefore the disease resistance increased. The direction of the additive effects at six loci qFsr1, qFsr2, qFsr8, qFsr10a, qFsr11 and qFsr12 coincided with that predicted by phenotypes of the parents, and the IR28 al eles at these loci had positive effect against rice false smut while the negative effects were found in Daguandao al eles at qFsr4 and qFsr10b. Both qFsr10a and qFsr11 should be useful in rice breeding for resistance to rice false smut in marker-assisted selection （MAS） program.
基金Supported by Agricultural S&T Innovation:Genetic Structure Analysis and Parasitism Fitness of U.virens in Anhui Province(14B1148)Special Fund for Talent Development:Pesticide Innovation and High-efficient Application Technology(13C1109)~~
文摘[Objective] This study aims to screen for the high effective fungicides which could significantly decrease the disease incidence and disease index of rice false smut. [Method] The inhibitory activities of the fungicide against mycelial growth of Ustilaginoidea virens were measured to in vitro evaluate the ECho values. And 17 fungicides were sprayed to evaluate the efficacy and effect of the fungicides tested in the field trials on the rice characters, [Result] The results showed that epoxicona- zole, difenoconazole, propiconazole and procloraz exhibited high inhibitory activity against mycelial growth of Ustilaginoidea virens with the ECso values 0.04, 0.07, 0.12 and 0.11 pg/ml, respectively. The results of field trials showed that the efficacy of Wen- quning, and fungicides such as difenoconazole, prochloraz, propiconazole, epoxi- conazole and their mixtures in controlling rice false smut were all 70% or more. [Conclusion] The 17 tested fungicides behaved efficacy in controlling rice false smut and did not cause drug injury on leaves and grains of rice plants, sprayed when flag leaves of rice fully expanded.
文摘[ Objective ] The paper was to establish the near isogenic lines of Huangzaosi maize with resistance against maize head smut, and to provide basis for its wide application in breeding and production. [Method] Combing with hybrid, backcress and self-cross method, as well as molecular markers, Huangzaosi maize was successfully introduced with head smut resistance, and its near isogenic lines were studied. The characteristics of resistant and susceptible variation and the changes of combining ability of near isogenic lines after backcrossing breeding were observed. [ Result ] The incidence rate of Huangzansi maize in control was 46% ; the incidence rates of the selected 24 near isogenic lines of resistant Huangzaosi were all lower than 10%, and the selected rate was 92.6% ; the combining ability of most near isogenic lines of resistant Huangzaosi maize had no significant difference with that of H^i maize in control; the yields of hybrids prepared by several inbred lines such as M135 and M140 were outstanding, which exceeded the control Zhengdan 958, showing a higher combining ability. [ Conclusion] The phenotype and combining ability of near isngenic lines of Huangzaosi maize with resistance against maize head smut obtained in the test were very close to Huan- gzaosi, and its resistance against maize head smut was greatly increased, thus solving the problems of Huangzaesi without resistance against maize head smut.
基金Supported by the National Natural Science Foundation of China(31071397)the Agricultural Science and Technology Innovation Fund Project of Jiangsu Province(CX(15)1054)~~
文摘In order to identify the resistant gene of rice false smut in rice, a recombi- nant inbred line （RILs） population with 157 lines derived from an inter-subspecies cross of Daguandao/IR28 by the single seed descent method was used to detect quantitative trait loci （QTLs） conferring resistance to strain Pi-1 of rice false smut caused by Usti/aginoiclea virens （Cooke） Takahashi in 2012 and 2013. The disease rate indexes of the two parents and 157 RILs caused by the strain Pi-1 of rice false smut were scored and the QTLs for rice false smut resistance were detected accordingly by QTL Cartographer software. Seven QTLs controlling false smut re- sistance were detected on chromosomes 2, 7, 8, 11 and 12, respectively, with the phenotypic variance of 8.5%-17.2%. There were four QTLs detected in 2012 and 2013, respectively, and only one QTL was found in both two years, the phenotypic variation explained by this individual QTL was 13.5% and 17.2%, and the additive effects of this QTL contributed to the 9.9% and 14.3% decrease of disease index and therefore the disease resistance increased. The direction of the additive effects at five loci qFsr2a, qFsr8a, qFsr8b, qFsr11 and qFsr12 coincided with that predicted by phenotypes of the parents, and the IR28 alleles at these loci had positive effect against rice false smut while the negative effects were found in Daguandao alleles at qFsr2b and qFsr7. The qFsr11 should be useful in rice breeding for resistance to rice false smut in marker-assisted selection （MAS） program.
文摘In order to test the control effect of 6% tebuconazole FS on maize head smut and to select its optimal dose for mixing seed, field tests were performed in 2012 and 2013. The results showed that 6% tebuconazole FS was effective to control maize head smut, and the control effect ranged from 73.4% to 91.1%. In addition, it also improved the maize yield by 36.7%-44.1%, compared with the blank control. The optimal dose of 6% tebuconazole FS for seed dressing was 166.5 g/100 kg to control head smut on maize.
基金funded by the Zhejiang Provincial Natural Science Foundation of China (Grant Nos. LQ19C140004 and LQ19C130007)the Chinese Academy of Agricultural Sciences under the ’Elite Youth’ Programthe Agricultural Sciences and Technologies Innovation Program of China (CAAS-ASTIP-2016-CNRRI)
文摘Rice false smut disease, which is caused by the fungus Ustilaginoidea virens, is currently one of the most devastating rice fungal diseases in the world. Rice false smut disease not only causes severe yield loss and grain quality reduction, but also threatens food safety due to its production of mycotoxins. In this review, the most recent progresses regarding the life cycle, infection processes, genome and genetic diversity, pathogenic gene and disease resistance in rice were summarized in order to provide theoretical basis for the control of U. virens. We also proposed some future directions and key questions that need to be addressed for a better understanding of the molecular mechanism that leads to rice false smut disease and the prospects for sustainable control of rice false smut.
基金financially supported by the National Natural Science Foundation of China(31271999)the Special Fund for Agro-scientific Research in the Public Interest,China(200903039-5)
文摘The sclerotia of Villosiclava virens were found commonly in high altitude and the temperate regions, where the temperatures are relatively low in rice filling stage. To make sure if low temperature induce the sclerotial formation in V. virens, the inoculated rice panicles in laboratory and the diseased rice panicles cut from paddy fields were treated under different temperatures. The results showed that 3 days of night temperature at 15°C were enough to induce the sclerotial formation. The low temperature was much more effective for young balls with intact membranes. After appearance of chlamydospores on the ball surfaces, the sclerotium could not differentiate anymore. The sclerotia began to differentiate below the chlamydospore layer and gradually grew onto the ball surfaces. This suggests that low temperature in the early development stage of false smut balls is an important factor to induce the sclerotial differentiation, and rice cultivars with long growth periods are able to produce more sclerotium-bearing balls, which will produce mass of spores in paddy field in the coming year.
文摘Rice false smut disease is an increasing concern for research and production, not only because of the increasing epidemic occurrence in rice production, but also the intriguing specific pathogenesis of the disease to be a unique pathological system to enrich the molecular mechanism of plant-microbe interaction. Progresses have been achieved in the pathogen phylogenetic placement, the alternative hosts, the pathogen morphology and diversity, the toxins generated by false smut balls, the artificial inoculation method, and the pathogen transformation as well as rice resistance to the disease. However, it is still controversy on the infection process. It is not clear how the life cycle of this pathogen is coupled with the disease cycle. This review summarized our current understanding on the pathogen, the pathogenesis, and the rice resistance to the disease. Future work should pay attention to developing a more rapid and effective system to evaluate rice resistance and susceptibility to the disease, screening of rice germplasm for disease-resistance breeding, studying the resistance inheritance, and investigating the molecular mechanism of rice-false smut fungus interaction.
基金Project supported by the National Natural Science Foundation of China(No.31070123)the Special Fund for Agro-scientific Research in the Public Interest of China(No.201003004)
文摘Ustilago coicis causes serious smut on Coix lacryma-jobi in Dayang Town,Jinyun County,Zhejiang Province of China.In this paper,ultrastructural assessments on fungus-host interactions and teliospore development are presented,and molecular phylogenetic analyses have been done to elucidate the phylogenetic placement of the taxon.Hyphal growth within infected tissues was both intracellular and intercellular and on the surface of fungus-host interaction,and the fungal cell wall and the invaginated host plasma membrane were separated by a sheath comprising two distinct layers between the fungal cell wall and the invaginated host plasma membrane.Ornamentation development of teliospore walls was unique as they appeared to be originated from the exosporium.In addition,internal transcribed spacer(ITS) and large subunit(LSU) sequence data showed that U.coicis is closely related to Ustilago trichophora which infects grass species of the genus Echinochloa(Poaceae).
文摘Ustilaginoidea virens is a flower-infecting fungus that forms false smut balls in rice panicle. Rice false smut has long been considered a minor disease, but recently it occurred frequently and emerged as a major disease in rice production. In vitro co-cultivation of U. virens strain with young rice panicles showed that U. virens enters inside of spikelets from the apex and then grows downward to infect floral organs. In response to U. virens infection, rice host exhibits elevated ROS accumulation and enhanced callose deposition. The secreted compounds of U. virens can suppress rice pollen germination. Examination of sectioning slides of freshly collected smut balls demonstrated that both pistil and stamens of rice flower are infected by U. virens, hyphae degraded the contents of the pollen cells, and also invaded the filaments. In addition, U. virens entered rice ovary through the thin-walled papillary cells of the stigma, then decomposed the integuments and infected the ovary. The invaded pathogen could not penetrate the epidermis and other layers of the ovary. Transverse section of the pedicel just below the smut balls showed that there were no fungal hyphae observed in the vascular bundles of the pedicel, implicating that U. virens is not a systemic flower-infecting fungus.
基金This work was financially supported by the Science and Technology Program in Guizhou Province,China(20162608,20162569)the High-Level Innovative Talents Training Project in Guizhou Province,China(20154016)the Southwest Guizhou of Science and Technology Program,China(2017-1-2).
文摘Smut is a serious disease in Job's tears,also known as adlay,and contributes to the reduction of crop yield in agricultural fields.In this study,the key pathogenic fungi in adlay smut disease were first identified by internal transcribed spacer region(ITS)high-throughput sequencing and then used to elucidate the composition and diversity of the fungal community in adlay smut.Results indicate that an abundance of operational taxonomic units(OTUs)were detected in the infected involucres of flowering plants and the OTUs were classified to nine phyla,20 classes,45 orders,90 families and 119 genera.A total of 4986 OTUs clustered together,sharing six core OTUs in all samples,while 145 OTUs were shared among four geographical groups.The Shannon and Simpson indices ranged from 0.137–1.629 and 0.357–0.970,respectively.Community diversity ranked as Anshun(AS)>Qinglong(QL)>Xingren(XR)>Xingyi(XY)among the four geographical groups by Shannon and Simpson indices,exhibiting complex community diversities among accessions and geographical groups.The richness and diversity data imply a weak relationship between the accession community richness and geographical origins of samples.Two closely related fungal genera,Sporisorium and Ustilago,were implicated as causes of smut disease.The genus Sporisorium appears to be more commonly found among accessions and thus is more likely to be the fungal pathogen causing smut in adlay.This work can facilitate strategies to control and prevent smut infection to improve adlay yield.
基金This research was funded by Zhejiang Provincial Natural Science Foundation of China(Grant No.LQ19C140004)Key Research and Development Project of Zhejiang Province(Grant No.2019C02018)the Chinese Academy of Agricultural Sciences under the‘Elite Youth’program,and the Agricultural Sciences and Technologies Innovation Program.We thank Prof.HUANG Junbin of Huazhong Agriculture University(Wuhan,China)for providing inoculum of the U.virens strain HWD-2.
文摘Ustilaginoidea virens is the causal agent of rice false smut,which can be a highly destructive disease of rice.The plasma membrane phosphatase Psr1 proteins,which act as a regulator of the salinity stress response in yeast,are widely distributed across fungi,but their functional characterization is sketchy.In this study,we characterized the functions of Psr1 protein,UvPsr1,in U.virens.Analyses of the AUvpsr1 and its complementation strain showed that UvPsr1 is required for normal mycelial growth,conidiation and tolerance to oxidative,osmotic and cell wall stresses.When rice panicles were inoculated with the AUvpsr1 strains,no symptoms of false smut disease developed,showing that UvPSR1 also contributes to the pathogenicity of the fungus.The deletion mutant of UvPSR1 also appeared to produce a smaller titer of toxic compounds able to inhibit elongation of the germinated seeds.In conclusion,our results indicated that UvPsr1 is a new pathogenic factor of U.virens.
基金funded by the Ministry of Agriculture of China (2013ZX08009003-001-007)the National High Technology Research and Development Program of China (2012AA101104, 2012AA10A306)
文摘Head smut, caused by the fungal pathogen Sporisorium reilianum, poses a grave threat to maize(Zea mays) production worldwide. Here we report cytological and molecular evidence for maize resistance to head smut. During early stages of root infection, S. reilianum mycelium was capable of penetrating the root epidermis of both resistant(Ji1037) and susceptible(HZ4) inbred lines. S. reilianum hyphae were observed in the root–stem junction at 6 days after inoculation. In an attempt to monitor hyphal spread within the maize plant,a highly specific and sensitive real-time PCR method was established to estimate the hyphal content in infected maize tissues. During the upward growth of endophytic S.reilianum, the extent of hyphal spread was markedly different between Ji1037 and HZ4. Very little or no pathogen was detected in aerial parts of Ji1037, whereas large amounts of pathogen accumulated in aboveground tissues, particularly inflorescences, of HZ4. Thus,maize resistance to S. reilianum was achieved mainly by inhibition of endophytic hyphal growth rather than by prevention of early-root penetration by the pathogen.
基金Supported by Major Science and Technology Project of Hunan Province(2013FJ1008)~~
文摘[Objective] The aim of this study was to explore the inheritance pattern of the resistance of two-line hybrid rice to false smut. [Method] A moderate susceptible TGMS line 33S as the female parent, was crossed with 30 susceptible restorer lines and 23 resistant restorer lines. Then false smut resistance of the hybrid F1 and parents were identified. [Result] All F1 of 33S crossed with 30 susceptible re- storer lines were susceptible to rice false smut. The F1 of 33S crossed with 23 re- sistant restorer lines showed dominant, incompletely dominant or recessive inheri- tance. Dominant and incompletely dominant inheritance accounted for 87.0%. The diseased panicle rate, disease index, average diseased grains per panicle, and the highest diseased grains per panicle of F1 shared highly significant positive correla- tions with corresponding indicators of restorer lines. [Conclusion] This study provides references for genetic improvement of two-line hybrid rice.
基金funded by the Zhejiang Provincial Natural Science Foundation of China(Grant No.LQ19C140004)the Key Research and Development Project of Zhejiang Province,China(Grant No.2019C02018)Key Research and Development Project of China National Rice Research Institute(Grant No.CNRRI-2020-04)。
文摘Some stress response-related genes have been identified in Ustilaginoidea virens,but it is not clear whether and how defects of stress responses affect the pathogenesis processes of U.virens.In this study,we identified a general stress response factor UvWHI2 as a homolog of Saccharomyces cerevisiae Whi2 in U.virens.The relative expression level of Uv Whi2 was significantly up-regulated during infection,suggesting that UvWHI2 may be involved in pathogenesis.Furthermore,knockout of Uv Whi2 showed decreased mycelial growth,increased conidiation in the potato sucrose medium and a defect in pathogenicity.In addition,the RNA-Seq and phenotypic analysis showed that UvWHI2 was involved in response to oxidative,hyperosmotic,cell wall stress and nutrient limitation.Further studies revealed that the defects of stress responses of the?Uvwhi2 mutant affected the formation of secondary spores on the nutrient limited surface and the rice surface,resulting in a significant reduction of pathogenicity of U.virens.Our results suggest that UvWHI2 is necessary for fungal growth,stress responses and the formation of secondary spores in U.virens.In addition,the defects of stress responses can affect the formation of secondary spores on the rice surface,and then compromise the pathogenicity of U.virens.
基金supported by‘Pioneer’and‘Leading Goose’R&D Program of Zhejiang Province,China(Grant No.2023C02014)Zhejiang Provincial Natural Science Foundation of China(Grant No.LY24C030002)+2 种基金Central Public-Interest Scientific Institution Basal Research Fund for China National Rice Research Institute(Grant No.CPSIBRF-CNRRI-202303)the China Agriculture Research System(Grant No.CARS-01)the Agricultural Science and Technology Innovation Program,China(Grant No.ASTIP)。
文摘Ustilaginoidea virens is a common rice pathogen that can easily lead to a decline in rice quality and the production of toxins pose potential risks to human health.In this review,we present a comprehensive literature review of research since the discovery of rice false smut.We provide a comprehensive and,at times,critical overview of the main results and findings from related research,and propose future research directions.Firstly,we delve into the interaction between U.virens and rice,including the regulation of transcription factors,the process of U.virens infecting rice panicles,and the plant immune response caused by rice infection.Following that,we discuss the identification and characterization of mycotoxins produced by the pathogenic fungus,as well as strategies for disease management.We emphasize the importance of comprehensive agricultural prevention and control methods for the sustainable management of U.virens.This knowledge will update our understanding of the interaction between U.virens and rice plants,offering a valuable perspective for those interested in U.virens.
