Maize transcription factor ZmBES1/BZR1-5 positively regulates kernel size
Maize transcription factor ZmBES1/BZR1-5 positively regulates kernel size
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玉米转录因子ZmBES1/BZR1-5正调控玉米籽粒大小
DOI：
10.1093/jxb/eraa544
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发表时间：
2021-02-27
影响因子：
6.9
通讯作者：
Yu, Haoqiang
中科院分区：
文献类型：
--
作者：
Sun, Fuai;Ding, Lei;Yu, Haoqiang
BES1/BZR1转录因子调控油菜素类固醇反应基因的表达，在植物发育中发挥关键作用，但它们在调节玉米籽粒发育中的作用尚不清楚。在本研究中，我们发现ZmBES1/BZR1-5正向调节籽粒大小。对513个玉米自交系候选基因的关联分析表明，与ZmBES1/BZR1-5相关的3个SNPs与粒宽显著相关，4个SNPs与百粒重相关。ZmBES1/BZR1-5在拟南芥和水稻中的过表达显著增加了种子的大小和重量，在玉米Mu转座子插入和EMS突变体中产生了较小的籽粒。ZmBES1/BZR1-5蛋白位于细胞核内，含有bHLH和BAM结构域，不具有单体转录活性，但通过BAM结构域形成同源二聚体。芯片测序、酵母单杂交和双荧光素酶分析表明，该蛋白与AP2/EREBP基因的启动子(Zm00001d010676和Zm00001d032077)结合并抑制其转录。文库筛选表明，ZmBES1/BZR1-5在体外和体内分别与酪蛋白激酶II亚基β4(ZmCKII Beta 4)和铁氧还蛋白2(ZmFdx2)相互作用。综上所述，我们的研究表明ZmBES1/BZR1-5正向调节籽粒大小，并为理解玉米籽粒发育的机制提供了新的见解。
The BES1/BZR1 transcription factors regulate the expression of genes responsive to brassinosteroids and play pivotal roles in plant development, but their role in regulating kernel development in maize remains unclear. In this study, we found that ZmBES1/BZR1-5 positively regulates kernel size. Association analysis of candidate genes in 513 diverse maize inbred lines indicated that three SNPs related to ZmBES1/BZR1-5 were significantly associated with kernel width and whilst four SNPs were related to 100-kernel weight. Overexpression of ZmBES1/BZR1-5 in Arabidopsis and rice both significantly increased seed size and weight, and smaller kernels were produced in maize Mu transposon insertion and EMS mutants. The ZmBES1/BZR1-5 protein locates in the nucleus, contains bHLH and BAM domains, and shows no transcriptional activity as a monomer but forms a homodimer through the BAM domain. ChIP-sequencing analysis, and yeast one-hybrid and dual-luciferase assays demonstrated that the protein binds to the promoters of AP2/EREBP genes (Zm00001d010676 and Zm00001d032077) and inhibits their transcription. cDNA library screening showed that ZmBES1/BZR1-5 interacts with casein kinase II subunit beta 4 (ZmCKII beta 4) and ferredoxin 2 (ZmFdx2) in vitro and in vivo, respectively. Taken together, our study suggests that ZmBES1/BZR1-5 positively regulates kernel size, and provides new insights into understanding the mechanisms of kernel development in maize.