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.
