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
[Objective] The aim was to study resistance of major and backup rice cul- tivars against Ustilaginoidea virens. [Method] Experiments and surveys were made on resistance of seventeen backup rice cultivars and some majo...[Objective] The aim was to study resistance of major and backup rice cul- tivars against Ustilaginoidea virens. [Method] Experiments and surveys were made on resistance of seventeen backup rice cultivars and some major cultivars in Anhui Province to identify resistance of different rice cultivars. [Result] Yanjing No.9, 80You 226, Tianxie No.l, A01 Xian, Lvjingnuo No.6 were moderate resistant; A03 Xian and Yangjing 636 were susceptible and the rest ten showed moderate susceptibility. Based on surveys on major rice cultivars, most of Liangyou rice series are suscept- able and novel Liangyou Xiang 4 enjoys resistance to certain extent. [Conclusion] The research provided references for resistance of rice against diseases in Anhui Province.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
[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
In order to determine population genetic structure and pathogenicity of Ustilaginoidea virens in the major rice-growing areas of Anhui Province, total 92 U. virens strains were collected from 28 rice-planting counties...In order to determine population genetic structure and pathogenicity of Ustilaginoidea virens in the major rice-growing areas of Anhui Province, total 92 U. virens strains were collected from 28 rice-planting counties （cities） of Anhui Province. Their genetic diversity was analyzed by using REP-PCR （repetitive extragenic palindromic sequence PCR）, and pathogenicity was determined with artificial inoculation method. The results showed that U. virens in rice-growing regions of Anhui Province had a rich genetic diversity. At the similarity level of 0.76, the 92 U. virens strains could be classified into 7 groups. Significant differences were found in pathogenicity among the 24 U. virens strains belonging to different groups, which showed no association with territorial source of U. virens strain or cluster method adopted by this study. Strain pathogenicity and rice varieties showed significant specificity.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
Korean spruce （Picea koraiensis Sieb. E1 Zucc.） is one of the main afforestation species in northern China. Seedling quality is a critical factor at planting time. To test whether the synergistic growth enhancement ...Korean spruce （Picea koraiensis Sieb. E1 Zucc.） is one of the main afforestation species in northern China. Seedling quality is a critical factor at planting time. To test whether the synergistic growth enhancement of Scotch pine （P. sylvestris var. mongolica） seedlings brought by the plant beneficial fungus Trichoderma virens （J.H. Mill., Giddens and A.A. Foster） Arx and ectomycorrhizal fungus （Suillus luteus （L.） Roussel.） can also benefit Korean spruce seed- lings, we examined the effects of S. luteus and T. virens on the growth of P. koraiensis seedlings and drought resistance of P. sylvestris var. mongolica in peat soils. The two fungi were added to sterilized peat soil in pots, and the plants were grown for 4 months. Seedling growth and physiological variables, including mycorrhizal colonization rate of roots, biomass, and chlorophyll content, were examined. The colonization rate of the mycorrhizal fungus on P. koraiensis exceeded 65 %, and the synergism between S. luteus and T. virens enhanced most of the variables for P. koraiensis seedlings after inoculation with S. luteus then 30 days later with T. virens as in our published results for seedlings of P. sylvestris var. mongolica. When seedlings of P. sylvestris var. mongolica were inoculated with this sequence, they became more drought tolerant. T. virens also induced S. luteus to produce -l,3-glucanase and chitinase. This inocu- lation sequence at planting can thus improve the quality of P. sylvestris var. mongolica and P. koraiensis seedlings and substantiates our previous results.展开更多
Transcription factors(TFs)orchestrate the regulation of cellular gene expression and thereby determine cell functionality.In this study,we analyzed the distribution of TFs containing domains,which named as ZnFTFs,both...Transcription factors(TFs)orchestrate the regulation of cellular gene expression and thereby determine cell functionality.In this study,we analyzed the distribution of TFs containing domains,which named as ZnFTFs,both in ascomycete and basidiomycete fungi.We found that ZnFTFs were widely distributed in these fungal species,but there was more expansion of the ZnFTF class in Ascomycota than Basidiomycota.We identified 40 ZnFTFs in Ustilaginoidea virens,and demonstrated the involvement of UvZnFTF1 in vegetative growth,conidiation,pigment biosynthesis and pathogenicity.RNA-Seq analysis suggested that UvZnFTF1 may regulate different nutrient metabolism pathways,the production of secondary metabolites,and the expression of pathogen-host interaction genes and secreted protein-encodi ng genes.Analysis of the distributi on of differe nt fungal TFs in U.virens further dem on strated that UvZnFTFs make up a large TF family and may play essential biological roles in U.virens.展开更多
In this research,the conditions for extraction of phenolics from leaves of Ficus virens were optimized using response surface methodology(RSM).The extraction abilities of phenolics(EAP) and flavonoids(EAF),the 2,2-dip...In this research,the conditions for extraction of phenolics from leaves of Ficus virens were optimized using response surface methodology(RSM).The extraction abilities of phenolics(EAP) and flavonoids(EAF),the 2,2-diphenyl-1-pierylhydrazyl(DPPH) free-radical scavenging potential,and the ferric reducing/antioxidant power(FRAP) were used as quality indicators.The results of single-factor experiments showed that temperature,ethanol concentration,extraction time,and the number of extraction cycles were the main influencing variables,and these provided key information for the central composite design.The results of RSM fitted well to a second degree polynomial model and more than 98% of the variability was explained.The ideal extraction conditions for EAP,EAF,DPPH free-radical scavenging potential,and FRAP were obtained.Considering the four quality indicators overall,the ideal extraction conditions were 58% ethanol at 57 °C for 37 min with three extraction cycles.At the ideal extraction conditions,the values of EAP,EAF,DPPH free-radical scavenging potential,and FRAP were 5.72%,3.09%,58.88 mg ascorbic acid equivalent(AAE)/g dry weight(DW),and 15.86 mg AAE/g DW,respectively.In addition,linear correlations were observed between EAP,EAF,and antioxidant potential.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
Rice false smut,which is caused by Ustilaginoidea virens,is an emerging disease of rice spikelets in rice-growing areas worldwide.However,the infection mechanism of U.virens on rice spikelets is still unclear.Here,we ...Rice false smut,which is caused by Ustilaginoidea virens,is an emerging disease of rice spikelets in rice-growing areas worldwide.However,the infection mechanism of U.virens on rice spikelets is still unclear.Here,we characterized a suppressor of mitogen-activated protein kinase kinase or ERK kinase(MEK)null(UvSMEKI)in U.virens that is conserved among filamentous fungi.Compared with wild type U.virens strain P-1,UvSMEKI deletion mutants were defective in pathogenicity and conidial germination.In addition,conidiation of UvSMEKI deletion mutants was significantly reduced on yeast extract tryptone(YT)plates,but inc「eased in YT broth compared with the wild type.Compared with UvSMEKI expression level during the vegetative mycelia and conidiation stages,UvSMEKI dramatically increased during infection of rice florets.Surprisingly,the UvSMEKI deletion mutants exhibited higher tolerance to H_(2)O_(2) and NaCl.In summary,presented evidence suggested that UvSMEKI positively regulated pathogenicity,conidial germination and conidiation in YT broth,and negatively regulated conidiation on YT medium and tolerance to oxidative and osmotic stresses.The results enhanee our understanding of the regulatory mechanism of pathogenicity of U.virens,and present a potential molecular target for blocking rice infection by U.virens.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
The fungus U. virens is the causal agent of rice false smut disease. The green fluorescent protein (GFP) was used to mark this fungus in order to visualize and analyze the colonization and infection processes in vivo....The fungus U. virens is the causal agent of rice false smut disease. The green fluorescent protein (GFP) was used to mark this fungus in order to visualize and analyze the colonization and infection processes in vivo. Using epifluorescence microscopy colonization and infection on rice roots were visualized in vivo. After inoculation for 2 to 15 d, it was observed that the conidia and their germ-tubes had penetrated into epidermis of young roots. The hyphae were found inside the root xylem 18 d after inoculation. Generally, the transformed fungus colonized the rhizosphere, the cortex as well as the vascular tissues with symptoms of root necrosis observed. The results of this work show that U. virens colonize not only rice panicles but also the roots.展开更多
bZIP proteins are widely distributed in eukaryotic organisms and regulate a diverse range of physiological processes.Several bZIP proteins have previously been identified in Ustilaginoidea virens.However,the biologica...bZIP proteins are widely distributed in eukaryotic organisms and regulate a diverse range of physiological processes.Several bZIP proteins have previously been identified in Ustilaginoidea virens.However,the biological roles of these bZIP proteins in this pathogen are still unknown.Here,one of these bZIP protein coding genes,UvATF21,was functionally characterized.Targeted deletion of UvATF21resulted in reduced conidiation and pathogenicity despite of the increased vegetative growth.The deletion mutants also significantly decreased the sensitivity to osmotic and oxidative stresses.Interestingly,deletion of UvATF21 exhibited different performances to cell wall integrity stress.These results indicated that UvATF21 played crucial roles in vegetative growth,conidiation,stress response,and full virulence in U.virens.展开更多
Dihydrochelerythrine(DHCHE)is an isoquinoline compound,which has distinct antifungal activity and can induce apoptosis.The antifungal activity of DHCHE against five rice pathogenic fungi was studied in vitro.At the co...Dihydrochelerythrine(DHCHE)is an isoquinoline compound,which has distinct antifungal activity and can induce apoptosis.The antifungal activity of DHCHE against five rice pathogenic fungi was studied in vitro.At the concentration of 7.5 mg/L,DHCHE exhibited the highest efficacy among tested compounds in inhibiting mycelium growth,with an inhibition rate of 68.8%in Ustilaginoidea virens,which was approximately 2.4 times of that of validamycin(28.7%).After exposure to DHCHE,transmission electron micrographs revealed spores showed incomplete organelles,malformed cell walls and nuclear membranes,as well as irregular lipid spheres.Reactive oxygen species accumulation in treated spores was markedly higher than that in control spores.DHCHE induced cell damage increased in a dose-dependent manner,as indicated by the decrease in mitochondrial membrane potential and initiation of apoptosis.The differences of expression levels of Fip1,ACP1,PMS2 and COX13 that are important for oxidative phosphorylation and mismatch repair pathway were significant,which may be some of the reasons for the induction of apoptosis in DHCHE-treated U.virens.The protein levels of Fip1,ACP1,PMS2 and COX13 agreed with protein fold change ratio from parallel reaction monitoring Gene Ontology terms and Kyoto Encyclopedia of Genes and Genomes pathway of differentially expressed proteins were further analyzed.These findings will help to elucidate the mechanisms associated with antifungal and pro-apoptotic effects of DHCHE on U.virens,thereby aiding the potential development of novel pesticides.展开更多
[Objective]The paper was to study optimum chemical agents and control periods against rice false smut( Ustilaginoidea virens) in single cropping middle-late rice. [Method]Taking chemical agents( triadimefon,armure,Jin...[Objective]The paper was to study optimum chemical agents and control periods against rice false smut( Ustilaginoidea virens) in single cropping middle-late rice. [Method]Taking chemical agents( triadimefon,armure,Jinggangmycin) as main treatments and spraying periods( within 7 d before initial heading stage,within 7 d before initial heading stage + initial heading stage,initial heading stage) as assisted treatments,the field efficacy trial and optimum control period of U. virens in single cropping middle-late rice were studied using Huanghuazhan and Jinnongsimiao as experimental materials in 2013. [Result] Three chemical agents,triadimefon,armure,Jinggangmycin,extremely reduced diseased panicle rate and disease index of U. virens,but there was no significant difference among three chemical agents. Spraying period did not have significant impact on diseased panicle rate and disease index of U. virens,whereas spraying within7 d before initial heading stage and during initial heading stage had relatively good control effect. Yield increased significantly after application of three chemical agents,and armure led to greater increase. The reason for yield increase was that seed setting rate was significantly increased,and the number of filled grains per panicle was significantly increased. Although spraying period influenced yield,the difference was not significant. [Conclusion] Triadimefon,armure and Jinggangmycin had good control effects against U. virens in single cropping middle-late rice,of which armure had better control effects. Spraying chemical agents increased seed setting rate,and further increased the number of filled grains per panicle and yield. Spraying within 7 d before initial heading stage and during initial heading stage had relatively better control effect against U. virens.展开更多
Rice false smut is caused by ascomycete Villosiclava virens, whose potential alternative hosts have been assumed previ- ously. Here its potential alternative hosts were surveyed and identified from 2008 to 2013 in the...Rice false smut is caused by ascomycete Villosiclava virens, whose potential alternative hosts have been assumed previ- ously. Here its potential alternative hosts were surveyed and identified from 2008 to 2013 in the main rice-growing regions in China. Two common weeds in paddy fields, Digitaria sanguinalis Scop. and Echinochloa crusgalli （L.） Beauv., were found to present the similar symptoms to smut diseases in a few individuals in 2012 and 2013 in Zhejiang and Sichuan provinces of China, respectively. After the examinations of the spore morphology, their infection and extension mode in hosts, pathogen cell wall components, and molecular identification, the two pathogens were identified to be the Basidiomycetes, Ustilago syntherismae and Ustilago trichophora, respectively. So far there has been no alternative host of V. virens to be identified in China. These suggest that the alternative hosts of V. virens, if they do exist, are not possible to play an important role in the pathogen life cycle and the disease epidemics.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 Demonstration and Extension Project of Technology Controlling Ustilaginoidea virens(11E1110)~~
文摘[Objective] The aim was to study resistance of major and backup rice cul- tivars against Ustilaginoidea virens. [Method] Experiments and surveys were made on resistance of seventeen backup rice cultivars and some major cultivars in Anhui Province to identify resistance of different rice cultivars. [Result] Yanjing No.9, 80You 226, Tianxie No.l, A01 Xian, Lvjingnuo No.6 were moderate resistant; A03 Xian and Yangjing 636 were susceptible and the rest ten showed moderate susceptibility. Based on surveys on major rice cultivars, most of Liangyou rice series are suscept- able and novel Liangyou Xiang 4 enjoys resistance to certain extent. [Conclusion] The research provided references for resistance of rice against diseases in Anhui Province.
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.
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.
基金Supported by Agricultural Science and Technology Innovation Fund of Anhui Province(14B1148)Special Fund for Talent Development in Anhui Province(13C1109)Science and Technology Major Project of Anhui Province(15CZZ03132)~~
文摘In order to determine population genetic structure and pathogenicity of Ustilaginoidea virens in the major rice-growing areas of Anhui Province, total 92 U. virens strains were collected from 28 rice-planting counties （cities） of Anhui Province. Their genetic diversity was analyzed by using REP-PCR （repetitive extragenic palindromic sequence PCR）, and pathogenicity was determined with artificial inoculation method. The results showed that U. virens in rice-growing regions of Anhui Province had a rich genetic diversity. At the similarity level of 0.76, the 92 U. virens strains could be classified into 7 groups. Significant differences were found in pathogenicity among the 24 U. virens strains belonging to different groups, which showed no association with territorial source of U. virens strain or cluster method adopted by this study. Strain pathogenicity and rice varieties showed significant specificity.
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the National Natural Science Foundation of China (31170597, 31200484)the National Fiveyear Science and Technology Research Project (2012BAD19B0801)+1 种基金the Fundamental Research Funds for the Central Universities (2572014AA30)the National Forestry Bureau ‘‘948’’ Project (2009-4-39) for financial support
文摘Korean spruce （Picea koraiensis Sieb. E1 Zucc.） is one of the main afforestation species in northern China. Seedling quality is a critical factor at planting time. To test whether the synergistic growth enhancement of Scotch pine （P. sylvestris var. mongolica） seedlings brought by the plant beneficial fungus Trichoderma virens （J.H. Mill., Giddens and A.A. Foster） Arx and ectomycorrhizal fungus （Suillus luteus （L.） Roussel.） can also benefit Korean spruce seed- lings, we examined the effects of S. luteus and T. virens on the growth of P. koraiensis seedlings and drought resistance of P. sylvestris var. mongolica in peat soils. The two fungi were added to sterilized peat soil in pots, and the plants were grown for 4 months. Seedling growth and physiological variables, including mycorrhizal colonization rate of roots, biomass, and chlorophyll content, were examined. The colonization rate of the mycorrhizal fungus on P. koraiensis exceeded 65 %, and the synergism between S. luteus and T. virens enhanced most of the variables for P. koraiensis seedlings after inoculation with S. luteus then 30 days later with T. virens as in our published results for seedlings of P. sylvestris var. mongolica. When seedlings of P. sylvestris var. mongolica were inoculated with this sequence, they became more drought tolerant. T. virens also induced S. luteus to produce -l,3-glucanase and chitinase. This inocu- lation sequence at planting can thus improve the quality of P. sylvestris var. mongolica and P. koraiensis seedlings and substantiates our previous results.
基金supported by the National Natural Science Foundation of China(Grant No.31601593)the Young Elite Scientist Sponsorship of China Association for Science and Technology(Grant No.YESS20170108)the Natural Science Foundation of Jiangsu Province,China(Grant No.BK20160588).
文摘Transcription factors(TFs)orchestrate the regulation of cellular gene expression and thereby determine cell functionality.In this study,we analyzed the distribution of TFs containing domains,which named as ZnFTFs,both in ascomycete and basidiomycete fungi.We found that ZnFTFs were widely distributed in these fungal species,but there was more expansion of the ZnFTF class in Ascomycota than Basidiomycota.We identified 40 ZnFTFs in Ustilaginoidea virens,and demonstrated the involvement of UvZnFTF1 in vegetative growth,conidiation,pigment biosynthesis and pathogenicity.RNA-Seq analysis suggested that UvZnFTF1 may regulate different nutrient metabolism pathways,the production of secondary metabolites,and the expression of pathogen-host interaction genes and secreted protein-encodi ng genes.Analysis of the distributi on of differe nt fungal TFs in U.virens further dem on strated that UvZnFTFs make up a large TF family and may play essential biological roles in U.virens.
基金Project supported by the National Natural Science Foundation of China(No.31070522)the Science and Technology Foundation of Fujian Province(No.2010N5013),China
文摘In this research,the conditions for extraction of phenolics from leaves of Ficus virens were optimized using response surface methodology(RSM).The extraction abilities of phenolics(EAP) and flavonoids(EAF),the 2,2-diphenyl-1-pierylhydrazyl(DPPH) free-radical scavenging potential,and the ferric reducing/antioxidant power(FRAP) were used as quality indicators.The results of single-factor experiments showed that temperature,ethanol concentration,extraction time,and the number of extraction cycles were the main influencing variables,and these provided key information for the central composite design.The results of RSM fitted well to a second degree polynomial model and more than 98% of the variability was explained.The ideal extraction conditions for EAP,EAF,DPPH free-radical scavenging potential,and FRAP were obtained.Considering the four quality indicators overall,the ideal extraction conditions were 58% ethanol at 57 °C for 37 min with three extraction cycles.At the ideal extraction conditions,the values of EAP,EAF,DPPH free-radical scavenging potential,and FRAP were 5.72%,3.09%,58.88 mg ascorbic acid equivalent(AAE)/g dry weight(DW),and 15.86 mg AAE/g DW,respectively.In addition,linear correlations were observed between EAP,EAF,and antioxidant potential.
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supported by the National Key Research and Development Project in China(Grant No.2016YFD200805)National Natural Science Foundation of China(Grant Nos.31301624 and 31571961).
文摘Rice false smut,which is caused by Ustilaginoidea virens,is an emerging disease of rice spikelets in rice-growing areas worldwide.However,the infection mechanism of U.virens on rice spikelets is still unclear.Here,we characterized a suppressor of mitogen-activated protein kinase kinase or ERK kinase(MEK)null(UvSMEKI)in U.virens that is conserved among filamentous fungi.Compared with wild type U.virens strain P-1,UvSMEKI deletion mutants were defective in pathogenicity and conidial germination.In addition,conidiation of UvSMEKI deletion mutants was significantly reduced on yeast extract tryptone(YT)plates,but inc「eased in YT broth compared with the wild type.Compared with UvSMEKI expression level during the vegetative mycelia and conidiation stages,UvSMEKI dramatically increased during infection of rice florets.Surprisingly,the UvSMEKI deletion mutants exhibited higher tolerance to H_(2)O_(2) and NaCl.In summary,presented evidence suggested that UvSMEKI positively regulated pathogenicity,conidial germination and conidiation in YT broth,and negatively regulated conidiation on YT medium and tolerance to oxidative and osmotic stresses.The results enhanee our understanding of the regulatory mechanism of pathogenicity of U.virens,and present a potential molecular target for blocking rice infection by U.virens.
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.
文摘The fungus U. virens is the causal agent of rice false smut disease. The green fluorescent protein (GFP) was used to mark this fungus in order to visualize and analyze the colonization and infection processes in vivo. Using epifluorescence microscopy colonization and infection on rice roots were visualized in vivo. After inoculation for 2 to 15 d, it was observed that the conidia and their germ-tubes had penetrated into epidermis of young roots. The hyphae were found inside the root xylem 18 d after inoculation. Generally, the transformed fungus colonized the rhizosphere, the cortex as well as the vascular tissues with symptoms of root necrosis observed. The results of this work show that U. virens colonize not only rice panicles but also the roots.
基金supported by the National Natural Science Foundation of China(Grant No.31701736)Key Research and Development Program of Hubei Province,China(Grant No.2021BBA236)National Key Research and Development Program,China(Grant No.2016YFD0300700)。
文摘bZIP proteins are widely distributed in eukaryotic organisms and regulate a diverse range of physiological processes.Several bZIP proteins have previously been identified in Ustilaginoidea virens.However,the biological roles of these bZIP proteins in this pathogen are still unknown.Here,one of these bZIP protein coding genes,UvATF21,was functionally characterized.Targeted deletion of UvATF21resulted in reduced conidiation and pathogenicity despite of the increased vegetative growth.The deletion mutants also significantly decreased the sensitivity to osmotic and oxidative stresses.Interestingly,deletion of UvATF21 exhibited different performances to cell wall integrity stress.These results indicated that UvATF21 played crucial roles in vegetative growth,conidiation,stress response,and full virulence in U.virens.
基金financially supported by the National Natural Science Foundation of China(Grant No.51678120).
文摘Dihydrochelerythrine(DHCHE)is an isoquinoline compound,which has distinct antifungal activity and can induce apoptosis.The antifungal activity of DHCHE against five rice pathogenic fungi was studied in vitro.At the concentration of 7.5 mg/L,DHCHE exhibited the highest efficacy among tested compounds in inhibiting mycelium growth,with an inhibition rate of 68.8%in Ustilaginoidea virens,which was approximately 2.4 times of that of validamycin(28.7%).After exposure to DHCHE,transmission electron micrographs revealed spores showed incomplete organelles,malformed cell walls and nuclear membranes,as well as irregular lipid spheres.Reactive oxygen species accumulation in treated spores was markedly higher than that in control spores.DHCHE induced cell damage increased in a dose-dependent manner,as indicated by the decrease in mitochondrial membrane potential and initiation of apoptosis.The differences of expression levels of Fip1,ACP1,PMS2 and COX13 that are important for oxidative phosphorylation and mismatch repair pathway were significant,which may be some of the reasons for the induction of apoptosis in DHCHE-treated U.virens.The protein levels of Fip1,ACP1,PMS2 and COX13 agreed with protein fold change ratio from parallel reaction monitoring Gene Ontology terms and Kyoto Encyclopedia of Genes and Genomes pathway of differentially expressed proteins were further analyzed.These findings will help to elucidate the mechanisms associated with antifungal and pro-apoptotic effects of DHCHE on U.virens,thereby aiding the potential development of novel pesticides.
基金Supported by National Science and Technology Support Program(2007BAD89B14)Special Fund for Agro-scientific Research in the Public Interest(00803028)+3 种基金Major Technical Research Project of Ministry of Agriculture for Agricultural Structure Adjustment(06-03-07B)Project of Guangdong Provincial Finance Department(YCY[2005]No.11,YCJ[2006]No.187)Agricultural Research Project of Guangdong Provincial Science and Technology Department(2005B20101001)Special Fund for Agro-scientific Research in the Public Interest(201103001)
文摘[Objective]The paper was to study optimum chemical agents and control periods against rice false smut( Ustilaginoidea virens) in single cropping middle-late rice. [Method]Taking chemical agents( triadimefon,armure,Jinggangmycin) as main treatments and spraying periods( within 7 d before initial heading stage,within 7 d before initial heading stage + initial heading stage,initial heading stage) as assisted treatments,the field efficacy trial and optimum control period of U. virens in single cropping middle-late rice were studied using Huanghuazhan and Jinnongsimiao as experimental materials in 2013. [Result] Three chemical agents,triadimefon,armure,Jinggangmycin,extremely reduced diseased panicle rate and disease index of U. virens,but there was no significant difference among three chemical agents. Spraying period did not have significant impact on diseased panicle rate and disease index of U. virens,whereas spraying within7 d before initial heading stage and during initial heading stage had relatively good control effect. Yield increased significantly after application of three chemical agents,and armure led to greater increase. The reason for yield increase was that seed setting rate was significantly increased,and the number of filled grains per panicle was significantly increased. Although spraying period influenced yield,the difference was not significant. [Conclusion] Triadimefon,armure and Jinggangmycin had good control effects against U. virens in single cropping middle-late rice,of which armure had better control effects. Spraying chemical agents increased seed setting rate,and further increased the number of filled grains per panicle and yield. Spraying within 7 d before initial heading stage and during initial heading stage had relatively better control effect against U. virens.
基金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Rice false smut is caused by ascomycete Villosiclava virens, whose potential alternative hosts have been assumed previ- ously. Here its potential alternative hosts were surveyed and identified from 2008 to 2013 in the main rice-growing regions in China. Two common weeds in paddy fields, Digitaria sanguinalis Scop. and Echinochloa crusgalli （L.） Beauv., were found to present the similar symptoms to smut diseases in a few individuals in 2012 and 2013 in Zhejiang and Sichuan provinces of China, respectively. After the examinations of the spore morphology, their infection and extension mode in hosts, pathogen cell wall components, and molecular identification, the two pathogens were identified to be the Basidiomycetes, Ustilago syntherismae and Ustilago trichophora, respectively. So far there has been no alternative host of V. virens to be identified in China. These suggest that the alternative hosts of V. virens, if they do exist, are not possible to play an important role in the pathogen life cycle and the disease epidemics.
