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
Tea plant (Camellia sinensis) has unique biological features for the study of cellular and molecular mechanisms, an evergreen broad-leaved woody plant which can accumulate selenium in soil abundant of Selenium. Expres...Tea plant (Camellia sinensis) has unique biological features for the study of cellular and molecular mechanisms, an evergreen broad-leaved woody plant which can accumulate selenium in soil abundant of Selenium. Expression of the genes related to Selenium (Se) metabolism is an adaptation to the soil environment for a long period. The purpose of the present study was to explore if there exist differences of expression about these genes in tea plant between growing in Selenium-abundant and normal soil. A quantitative real-time reverse transcription polymerase chain reaction (Q-RT-PCR) assay was done for quantification of ATP sulfurylase (APS) and selenocysteine methyltransferase (SMT) mRNA normalized to Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene in tea plant. Young leaves, mature leaves and tender roots from tea plants growing in soil abundant of Selenium were respectively obtained from Shitai County, Anhui Province, and also the relevant materials of the selenium un-enriched tea plant planted at agricultural garden of Ahui Agriculture University were taken as control for real-time PCR analysis. The results showed that APS1, APS2 and SMT expression levels for either young or mature leaves in selenium-enriched tea plant were lower than that in ordinary (selenium un-enriched) tea plant. In contrast, the APS1, APS2 and SMT expression level of roots in selenium-enriched tea plant were all higher than that in ordinary tea plant. APS1 gene expression level of roots in selenium-enriched tea plant was about 1.6 times higher than that in the ordinary tea plant, APS2 gene expression level was about 4.8-fold higher than that in the ordinary tea plant, SMT gene expression level was about 3.3 times higher than that in the ordinary tea plant. Among various tissues of selenium-enriched tea plant, APS1 gene relative expression level of young leaves was similar to or slightly higher than mature leaves, and the one of roots was the lowest among them;APS2 gene relative expression level of young leaves was similar to or slig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.
文摘Tea plant (Camellia sinensis) has unique biological features for the study of cellular and molecular mechanisms, an evergreen broad-leaved woody plant which can accumulate selenium in soil abundant of Selenium. Expression of the genes related to Selenium (Se) metabolism is an adaptation to the soil environment for a long period. The purpose of the present study was to explore if there exist differences of expression about these genes in tea plant between growing in Selenium-abundant and normal soil. A quantitative real-time reverse transcription polymerase chain reaction (Q-RT-PCR) assay was done for quantification of ATP sulfurylase (APS) and selenocysteine methyltransferase (SMT) mRNA normalized to Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene in tea plant. Young leaves, mature leaves and tender roots from tea plants growing in soil abundant of Selenium were respectively obtained from Shitai County, Anhui Province, and also the relevant materials of the selenium un-enriched tea plant planted at agricultural garden of Ahui Agriculture University were taken as control for real-time PCR analysis. The results showed that APS1, APS2 and SMT expression levels for either young or mature leaves in selenium-enriched tea plant were lower than that in ordinary (selenium un-enriched) tea plant. In contrast, the APS1, APS2 and SMT expression level of roots in selenium-enriched tea plant were all higher than that in ordinary tea plant. APS1 gene expression level of roots in selenium-enriched tea plant was about 1.6 times higher than that in the ordinary tea plant, APS2 gene expression level was about 4.8-fold higher than that in the ordinary tea plant, SMT gene expression level was about 3.3 times higher than that in the ordinary tea plant. Among various tissues of selenium-enriched tea plant, APS1 gene relative expression level of young leaves was similar to or slightly higher than mature leaves, and the one of roots was the lowest among them;APS2 gene relative expression level of young leaves was similar to or slig
