Twenty-two nitrate nonutilizing （nit） mutants were recovered from five wild-type isolates of Fusarium graminearum and fifty nit mutants were recovered from three JS399-19-resistant mutants of F. graminearum cultured...Twenty-two nitrate nonutilizing （nit） mutants were recovered from five wild-type isolates of Fusarium graminearum and fifty nit mutants were recovered from three JS399-19-resistant mutants of F. graminearum cultured on MMC medium. Some biological properties were compared between nit mutants and their parental isolates. The results showed that there were no significant differences in growth rate, cultural characters or pathogenicity between JS399-19-resistant nit mutants and their parental isolates. But the conidial production and the sexual reproduction ability changed to some extent. There was no cross resistance toward chlorate and JS399-19 in F. graminearum and the resistance could be stable through 20-time subcultures. Therefore, the nit could be used as a genetic marker for studying the genetics of JS399-19 resistance in E graminearum, which was used to study JS399-19 resistance transferability in hyphal fusion. Resistance in JS399-19 could not be transferred by hyphal fusion or could be transferred with low chance between two compatible isolates, which would delay the development of JS399-19 resistance in the field.展开更多
Hyphal fusion(anastomosis)is a common process serving many important functions at various developmental stages in the life cycle of ascomycetous fungi.However,the biological roles and molecular mechanisms in plant pat...Hyphal fusion(anastomosis)is a common process serving many important functions at various developmental stages in the life cycle of ascomycetous fungi.However,the biological roles and molecular mechanisms in plant pathogenic fungi were widely unknown.In this study,a hyphal fusion protein FpHam-2 was screened from a T-DNA insertion mutant library of Fusarium pseudograminearum,and FpHam-2 interacts with another 2 hyphal fusion protein homologues FpHam-3 and FpHam-4.Each of these 3 genes deletion mutant revealed in similar defective phenotypes compared with the WT and complemented strains,including reduction in growth rate,defects in hyphal fusion and conidiation,more sensitive for cell membrane,cell wall and oxidative stress responses,and decreased in virulence.The yeast two-hybrid assay was used to identify that FpHam-2 interacts with 3 autophagy-related proteins,including FpAtg3,FpAtg28 and FpAtg33.Furthermore,FpHam-2-deletion mutant showed decreased accumulation of autophagic bodies in hypha.In conclusion,FpHam-2,FpHam-3 and FpHam-4 have an essential role for hyphal fusion and regulating the growth,conidiation and virulence in F.pseudograminearum.展开更多
The rice blast,caused by fungus Magnaporthe oryzae,is a major constraint to the world food security.Hyphal growth is the foundation of fungal development and proliferation of fungi.To investigate genes involved in hyp...The rice blast,caused by fungus Magnaporthe oryzae,is a major constraint to the world food security.Hyphal growth is the foundation of fungal development and proliferation of fungi.To investigate genes involved in hyphal growth of this fungus,digital gene expression tag profiling was used to compare a previously generated temperature-sensitive mutant which defect at hyphae growth and reduction on pathogenicity,with its related wildtype strain.416 genes were detected as differential expression,178 of which were specifically expressed in Guy-11 but down-regulated expression in the mutant.Functional classification analysis revealed the phenotype mutation may be mainly caused by a defection in translational and vacuole- related processes.The results and the protocol used will improve our knowledge on morphogenesis and promote the further study on M.oryzae pathogenesis.展开更多
Although genome-wide A-to-I editing mediated by adenosine-deaminase-acting-on-tRNA(ADAT)occurs during sexual reproduction in the presence of stage-specific cofactors,RNA editing is not known to occur during vegetative...Although genome-wide A-to-I editing mediated by adenosine-deaminase-acting-on-tRNA(ADAT)occurs during sexual reproduction in the presence of stage-specific cofactors,RNA editing is not known to occur during vegetative growth in filamentous fungi.Here we identified 33 A-to-I RNA editing events in vegetative hyphae of Fusarium graminearum and functionally characterized one conserved hyphal-editing site.Similar to ADAT-mediated editing during sexual reproduction,majority of hyphal-editing sites are in coding sequences and nonsynonymous,and have strong preference for U at-1 position and hairpin loops.Editing at TA^(437)G,one of the hyphal-specific editing sites,is a premature stop codon correction(PSC)event that enables CHE1 gene to encode a full-length zinc fingertranscription factor.Manual annotations showed that this PSC site is conserved in CHE1 orthologs from closely-related Fusarium species.Whereas the che1 deletion and CHE1^(TAA)(G^(438)to A)mutants had no detectable phenotype,the CHE1TGG(A437 to G)mutant was defective in hyphal growth,conidiation,sexual reproduction,and plant infection.However,the CHE1TGG mutant was increased in tolerance against oxidative stress and editing of TA^(437)G in CHE1 was stimulated by H_(2)O_(2)treatment in F.graminearum.These results indicate that fixation of the premature stop codon in CHE1 has a fitness cost on normal hyphal growth and reproduction but provides a benefit to tolerance against oxidative stress.Taken together,A-to-I editing events,although rare(not genome-wide),occur during vegetative growth and editing in CHE1 plays a role in response to oxidative stress in F.graminearum and likely in other fungal pathogens.展开更多
基金This work was supported by the State "973" Programs from the Ministry of Science and Technology of China (No. 2006CB101900)Technology and the Project (No. 20050307028)+3 种基金from the Ministry of Education of China, the National Natural Science Foundation of China (No. 30671048 & No. 30671384)Jiangsu Provincial Program for Tackling Key Problems of Science and Technology (No. BG2006328)the Key Technology R & D program from the Ministry of Science and Technology of China (No. 2006BAE01A04-08)the state "863" programs from the Ministry of Science and Technology of China (No. 2006AA10A211).
文摘Twenty-two nitrate nonutilizing （nit） mutants were recovered from five wild-type isolates of Fusarium graminearum and fifty nit mutants were recovered from three JS399-19-resistant mutants of F. graminearum cultured on MMC medium. Some biological properties were compared between nit mutants and their parental isolates. The results showed that there were no significant differences in growth rate, cultural characters or pathogenicity between JS399-19-resistant nit mutants and their parental isolates. But the conidial production and the sexual reproduction ability changed to some extent. There was no cross resistance toward chlorate and JS399-19 in F. graminearum and the resistance could be stable through 20-time subcultures. Therefore, the nit could be used as a genetic marker for studying the genetics of JS399-19 resistance in E graminearum, which was used to study JS399-19 resistance transferability in hyphal fusion. Resistance in JS399-19 could not be transferred by hyphal fusion or could be transferred with low chance between two compatible isolates, which would delay the development of JS399-19 resistance in the field.
基金supported by the grants from the National Natural Science Foundation of China(U2004140)the Henan Provincial Science and Technology Major Project,China(221100110100)。
文摘Hyphal fusion(anastomosis)is a common process serving many important functions at various developmental stages in the life cycle of ascomycetous fungi.However,the biological roles and molecular mechanisms in plant pathogenic fungi were widely unknown.In this study,a hyphal fusion protein FpHam-2 was screened from a T-DNA insertion mutant library of Fusarium pseudograminearum,and FpHam-2 interacts with another 2 hyphal fusion protein homologues FpHam-3 and FpHam-4.Each of these 3 genes deletion mutant revealed in similar defective phenotypes compared with the WT and complemented strains,including reduction in growth rate,defects in hyphal fusion and conidiation,more sensitive for cell membrane,cell wall and oxidative stress responses,and decreased in virulence.The yeast two-hybrid assay was used to identify that FpHam-2 interacts with 3 autophagy-related proteins,including FpAtg3,FpAtg28 and FpAtg33.Furthermore,FpHam-2-deletion mutant showed decreased accumulation of autophagic bodies in hypha.In conclusion,FpHam-2,FpHam-3 and FpHam-4 have an essential role for hyphal fusion and regulating the growth,conidiation and virulence in F.pseudograminearum.
基金supported by the Natural Science Foundation of Zhejiang Province,China(Y3110028 and LQ12C14003)
文摘The rice blast,caused by fungus Magnaporthe oryzae,is a major constraint to the world food security.Hyphal growth is the foundation of fungal development and proliferation of fungi.To investigate genes involved in hyphal growth of this fungus,digital gene expression tag profiling was used to compare a previously generated temperature-sensitive mutant which defect at hyphae growth and reduction on pathogenicity,with its related wildtype strain.416 genes were detected as differential expression,178 of which were specifically expressed in Guy-11 but down-regulated expression in the mutant.Functional classification analysis revealed the phenotype mutation may be mainly caused by a defection in translational and vacuole- related processes.The results and the protocol used will improve our knowledge on morphogenesis and promote the further study on M.oryzae pathogenesis.
基金supported by grants from NNSF to HQL and from NSF and USWBSI to JX.
文摘Although genome-wide A-to-I editing mediated by adenosine-deaminase-acting-on-tRNA(ADAT)occurs during sexual reproduction in the presence of stage-specific cofactors,RNA editing is not known to occur during vegetative growth in filamentous fungi.Here we identified 33 A-to-I RNA editing events in vegetative hyphae of Fusarium graminearum and functionally characterized one conserved hyphal-editing site.Similar to ADAT-mediated editing during sexual reproduction,majority of hyphal-editing sites are in coding sequences and nonsynonymous,and have strong preference for U at-1 position and hairpin loops.Editing at TA^(437)G,one of the hyphal-specific editing sites,is a premature stop codon correction(PSC)event that enables CHE1 gene to encode a full-length zinc fingertranscription factor.Manual annotations showed that this PSC site is conserved in CHE1 orthologs from closely-related Fusarium species.Whereas the che1 deletion and CHE1^(TAA)(G^(438)to A)mutants had no detectable phenotype,the CHE1TGG(A437 to G)mutant was defective in hyphal growth,conidiation,sexual reproduction,and plant infection.However,the CHE1TGG mutant was increased in tolerance against oxidative stress and editing of TA^(437)G in CHE1 was stimulated by H_(2)O_(2)treatment in F.graminearum.These results indicate that fixation of the premature stop codon in CHE1 has a fitness cost on normal hyphal growth and reproduction but provides a benefit to tolerance against oxidative stress.Taken together,A-to-I editing events,although rare(not genome-wide),occur during vegetative growth and editing in CHE1 plays a role in response to oxidative stress in F.graminearum and likely in other fungal pathogens.
