Starch serves as a critical storage component,significantly influencing the grain yield and quality of maize(Zea mays L.).Understanding the genetic basis of natural variation in kernel starch content(SC)is essential f...Starch serves as a critical storage component,significantly influencing the grain yield and quality of maize(Zea mays L.).Understanding the genetic basis of natural variation in kernel starch content(SC)is essential for maize breeding to meet future demands.A genome-wide association study(GWAS)identified 84 and 96 loci associated with kernel SC across two years,overlapping with 185 candidate genes.The candidate gene Zm MYB71,encoding a MYB-related transcription factor,demonstrated the highest co-expression frequency with starch synthesis genes.Analysis revealed that Zm MYB71 functions as a nuclear located transcription repressor,and mutants exhibited increased kernel SC by over 2.32%,with minimal impact on amylose content or 100-grain weight.Sh1,Sh2,and GBSSI exhibited up-regulation in mutants by 1.56-,1.45-and 1.32-fold,respectively,aligning with RNA sequencing results;their promoter activities appear directly repressed by Zm MYB71 through the GATATC and TTAGGG motifs.Additionally,the Zm MYB71 elite haplotype Hap1 occurred in over 55%of the high-starch maize sub-populations Iowa Stiff Stalk Synthetic(BSSS)and Partner B(PB),but only in 7.14%of the low-starch sub-population Partner A(PA).Analysis of Hap1 haplotype frequencies across breeding stages revealed a significant increase to 40.28%in inbred groups released after 2010,compared to 28.57 and 27.94%in 1980 and 1990,and 2000,respectively.These findings enhance understanding of natural variation in maize kernel SC and establish Zm MYB71 as a negative regulator with potential applications in SC improvement.展开更多
基金the financial support from the National Key Research and Development Program of China(2021YFD1201004)the Science and Technology Innovation Project,Chinese Academy of Agricultural Sciences(CAAS-ZDRW202201)the Shandong Provincial Key R&D Program,China(2023LZGC010)。
文摘Starch serves as a critical storage component,significantly influencing the grain yield and quality of maize(Zea mays L.).Understanding the genetic basis of natural variation in kernel starch content(SC)is essential for maize breeding to meet future demands.A genome-wide association study(GWAS)identified 84 and 96 loci associated with kernel SC across two years,overlapping with 185 candidate genes.The candidate gene Zm MYB71,encoding a MYB-related transcription factor,demonstrated the highest co-expression frequency with starch synthesis genes.Analysis revealed that Zm MYB71 functions as a nuclear located transcription repressor,and mutants exhibited increased kernel SC by over 2.32%,with minimal impact on amylose content or 100-grain weight.Sh1,Sh2,and GBSSI exhibited up-regulation in mutants by 1.56-,1.45-and 1.32-fold,respectively,aligning with RNA sequencing results;their promoter activities appear directly repressed by Zm MYB71 through the GATATC and TTAGGG motifs.Additionally,the Zm MYB71 elite haplotype Hap1 occurred in over 55%of the high-starch maize sub-populations Iowa Stiff Stalk Synthetic(BSSS)and Partner B(PB),but only in 7.14%of the low-starch sub-population Partner A(PA).Analysis of Hap1 haplotype frequencies across breeding stages revealed a significant increase to 40.28%in inbred groups released after 2010,compared to 28.57 and 27.94%in 1980 and 1990,and 2000,respectively.These findings enhance understanding of natural variation in maize kernel SC and establish Zm MYB71 as a negative regulator with potential applications in SC improvement.
