Variation in Rubisco activase(RCAβ)gene promoters and expression in soybean[Glycine max(L.)Merr.]

【作者】 晁毛妮； 印志同； 郝德荣； 张晋玉； 宋海娜； 宁爱玲； 许晓明； 喻德跃；

【Author】 CHAO Mao-ni;YIN Zhi-tong;HAO Derong;ZHANG Jin-yu;SONG Hai-na;NING Ai-ling;XU Xiao-ming;YU De-yue;National Center for Soybean Improvement,Nanjing Agricultural University;

【机构】 南京农业大学/国家大豆改良中心；

【摘要】 Understanding the genetic basis of Rubisco activase(RCA)gene regulation and altering its expression levels to optimize Rubisco activation may provide an approach to enhance plant productivity.However,the genetic mechanisms and the effect of RCA expression on phenotype are still unknown in soybean.This work analysed the expression of RCA genes and demonstrated that two RCA isoforms presented different expression patterns.Compared with GmRCAa,GmRCAβwas expressed at higher mRNA and protein levels.In addition,GmRCAa and GmRCAβwere positively correlated with chlorophyll fluorescence parameters and seed yield,suggesting that changes in expression of RCA has a potential applicability in breeding for enhanced soybean productivity.To identify the genetic factors that cause expression level variation of GmRCAβ,expression quantitative trait loci(eQTL)mapping was combined with allele mining in a natural population including 219 landraces.The eQTL mapping showed that a combination of both cisand transacting eQTLs might control GmRCAβexpression.As promoters can affect both cis-and trans-acting eQTLs by altering cis-acting regulatory elements or transcription factor binding sites,this work subsequently focused on the promoter region of GmRCAβ.Single-nucleotide polymorphisms in the GmRCAβpromoter were identified and shown to correlate with expression level diversity.These SNPs were classified into two groups,A and B.Further transient expression showed that GUS expression driven by the group A promoter was stronger than that by the group B promoter,suggesting that promoter sequence types could influence gene expression levels.These results would improve understanding how variation within promoters affects gene expression and,ultimately,phenotypic diversity in natural populations.更多还原

【Abstract】 Understanding the genetic basis of Rubisco activase(RCA) gene regulation and altering its expression levels to optimize Rubisco activation may provide an approach to enhance plant productivity.However,the genetic mechanisms and the effect of RCA expression on phenotype are still unknown in soybean.This work analysed the expression of RCA genes and demonstrated that two RCA isoforms presented different expression patterns.Compared with GmRCAa,GmRCAβwas expressed at higher mRNA and protein levels.In addition,GmRCAa and GmRCAβ were positively correlated with chlorophyll fluorescence parameters and seed yield,suggesting that changes in expression of RCA has a potential applicability in breeding for enhanced soybean productivity.To identify the genetic factors that cause expression level variation of GmRCAβ,expression quantitative trait loci(eQTL) mapping was combined with allele mining in a natural population including 219 landraces.The eQTL mapping showed that a combination of both cisand transacting eQTLs might control GmRCAβ expression.As promoters can affect both cis-and trans-acting eQTLs by altering cis-acting regulatory elements or transcription factor binding sites,this work subsequently focused on the promoter region of GmRCAβ.Single-nucleotide polymorphisms in the GmRCAβ promoter were identified and shown to correlate with expression level diversity.These SNPs were classified into two groups,A and B.Further transient expression showed that GUS expression driven by the group A promoter was stronger than that by the group B promoter,suggesting that promoter sequence types could influence gene expression levels.These results would improve understanding how variation within promoters affects gene expression and,ultimately,phenotypic diversity in natural populations.更多还原