Selenocysteine methyltransferase(SMT)is a key enzyme involved in the Se metabolism pathway,and it is responsible for the catalysis of Se-methylselenocysteine(SeMSC)compound formation.Previous studies showed that selen...Selenocysteine methyltransferase(SMT)is a key enzyme involved in the Se metabolism pathway,and it is responsible for the catalysis of Se-methylselenocysteine(SeMSC)compound formation.Previous studies showed that selenium treatment activated SMT expression and promoted the accumulation of glucosinolates(GSLs)and sulforaphane,but the roles and functional mechanisms of SMT in mediating GSLs and sulforaphane synthesis remain unclear.In this study,we identified the BoSMT gene in broccoli and uncovered its roles in mediating GSLs biosynthesis.Transgenic assays revealed that BoSMT is involved in SeMSC biosynthesis in broccoli.More importantly,the contents of GSLs and sulforaphane were significantly increased in the BoSMT-overexpressing broccoli lines but decreased in the knockdown lines,suggesting that BoSMT played a positive role in regulating GSLs and sulforaphane synthesis.Further evidence indicated that BoSMT-mediated overaccumulation of GSLs and sulforaphane might be due to the increase in the endogenous SeMSC content.Compared with the mock(water)treatment,selenite-induced significantly increases of the SeMSC content in the BoSMT-knockdown plants partially compensated the phenotype of GSLs and sulforaphane loss.Compared with the mock treatment,exogenous SeMSC treatment significantly increased the contents of GSL and sulforaphane and activated GSL synthesis-related gene expression,suggesting that SeMSC acted as a positive regulator for GSL and sulforaphane production.Our findings provided novel insights into selenium-mediated GSLs and sulforaphane accumulation.The genetic manipulation of BoSMT might be a useful strategy for improving the dietary nutritional values of broccoli.展开更多
Anther dehiscence controls optimal interaction between pollen and stigma,thereby determining the successful sexual reproduction.The regulators or mechanisms of this process remain elusive.Here,two CRISPR/Cas9 mutants ...Anther dehiscence controls optimal interaction between pollen and stigma,thereby determining the successful sexual reproduction.The regulators or mechanisms of this process remain elusive.Here,two CRISPR/Cas9 mutants of a rice exocyst subunit gene SEC3A,sec3a-1 and sec3a-2,showed anther indehiscence at anthesis and male sterility at maturity.Pollen viability and germination in the mutants were partly defective,whereas their female gametes undergone a normal development.Hybrid or self-pollinated seeds could be produced by artificial pollination,suggesting potential use of a weak sec3a mutant as a female line during hybrid breeding.SEC3A is widely expressed in various tissues,including anther walls.Further results showed an excessive IAA accumulation and no endothecium lignification in sec3a-1/2 anthers.Our findings suggest that SEC3A appears to regulate anther dehiscence by modulating auxin signaling,providing insights into regulation of anther dehiscence and function of exocyst in plants.展开更多
基金the Projects of International Cooperation National Key R&D Program of China(Grant No.2022YFE0108300)the National Key Research and Development Program of China(Grant No.2022YFF1003000)the National Natural Science Foundation of China(Grant Nos.32372682,32272747,32072585,32072568).
文摘Selenocysteine methyltransferase(SMT)is a key enzyme involved in the Se metabolism pathway,and it is responsible for the catalysis of Se-methylselenocysteine(SeMSC)compound formation.Previous studies showed that selenium treatment activated SMT expression and promoted the accumulation of glucosinolates(GSLs)and sulforaphane,but the roles and functional mechanisms of SMT in mediating GSLs and sulforaphane synthesis remain unclear.In this study,we identified the BoSMT gene in broccoli and uncovered its roles in mediating GSLs biosynthesis.Transgenic assays revealed that BoSMT is involved in SeMSC biosynthesis in broccoli.More importantly,the contents of GSLs and sulforaphane were significantly increased in the BoSMT-overexpressing broccoli lines but decreased in the knockdown lines,suggesting that BoSMT played a positive role in regulating GSLs and sulforaphane synthesis.Further evidence indicated that BoSMT-mediated overaccumulation of GSLs and sulforaphane might be due to the increase in the endogenous SeMSC content.Compared with the mock(water)treatment,selenite-induced significantly increases of the SeMSC content in the BoSMT-knockdown plants partially compensated the phenotype of GSLs and sulforaphane loss.Compared with the mock treatment,exogenous SeMSC treatment significantly increased the contents of GSL and sulforaphane and activated GSL synthesis-related gene expression,suggesting that SeMSC acted as a positive regulator for GSL and sulforaphane production.Our findings provided novel insights into selenium-mediated GSLs and sulforaphane accumulation.The genetic manipulation of BoSMT might be a useful strategy for improving the dietary nutritional values of broccoli.
基金supported by the Science Fund for Creative Research Groups of the National Natural Science Foundation of China(32171970)the Chongqing Outstanding Scientists Project(cstc2022ycjh-bgzxm0073)the Natural Science Foundation of Chongqing,China(cstc2021jcyj-cxttX0004)。
文摘Anther dehiscence controls optimal interaction between pollen and stigma,thereby determining the successful sexual reproduction.The regulators or mechanisms of this process remain elusive.Here,two CRISPR/Cas9 mutants of a rice exocyst subunit gene SEC3A,sec3a-1 and sec3a-2,showed anther indehiscence at anthesis and male sterility at maturity.Pollen viability and germination in the mutants were partly defective,whereas their female gametes undergone a normal development.Hybrid or self-pollinated seeds could be produced by artificial pollination,suggesting potential use of a weak sec3a mutant as a female line during hybrid breeding.SEC3A is widely expressed in various tissues,including anther walls.Further results showed an excessive IAA accumulation and no endothecium lignification in sec3a-1/2 anthers.Our findings suggest that SEC3A appears to regulate anther dehiscence by modulating auxin signaling,providing insights into regulation of anther dehiscence and function of exocyst in plants.
