中国玉米单产仅实现48%的潜力（美国77%），磷生物有效性差是制约大量中低产田玉米单产提高的突出因素。MYB转录因子在胁迫响应过程中起重要调控作用，但缺乏深入功能研究。我们发现，ZmMYB95存在可变剪接（ZmMYB95-1和ZmMYB95-2），两个转录本具有不同的低磷增强表达模式，但GFP融合蛋白均定位于细胞核；ZmMYB95-2在酵母系统能结合更多的苯丙烷代谢途径关键基因；重要的是，ZmMYB95过表达玉米株系在低磷条件优先将磷素向地上部转移而更耐低磷胁迫。本课题将深入研究野生玉米和玉米MYB95序列特征、可变剪接区域组蛋白H3甲基化特征、对照和低磷条件的表达特征；ZmMYB95定位，两个转录本是否差异调控类黄酮代谢、生长素分布、菌根侵染；玉米转基因株系生理和生物学表型；ZmMYB95靶基因、互作蛋白、基因调控网络。课题具有重要的植物营养学、遗传学、生态学价值和育种应用前景。

Grain yields only reach 48% of yield potential in maize production in China in contrast to 77% of that in USA. In low- and middle-yield fields, low bioavailability of phosphorus is a major limitation factor for maize production. MYB transcription factors play essential regulatory roles in maize in response to environmental stresses; however, functional characterization remains very limited. We found that ZmMYB95 has two iso-transcripts with distinct response patterns to low phosphorus. GFP tagged ZmMYB95-1 and ZmMYB95-2 are localized to the nucleus. In the yeast, ZmMYB95-2 binds to the promoter region of more key genes regulating phenylpropanoid metabolism. Importantly, ZmMYB95 overexpression makes maize plants more low-phosphorus resistant by preferentially allocating phosphorus towards the shoot under the low phosphorus condition. This proposal will further investigate 1) promoter sequences, coding sequences, histone H3 methylation patterns of alternative splicing regions, expression patterns of MYB95 in maize and teosintes under control and low phosphorus conditions; 2) localization of ZmMYB95, differential regulation of flavonoid metabolism, IAA distribution, and IMF infection by ZmMYB95-1 and ZmMYB95-2; 3) physiological and biological phenotypes of ZmMYB95-1 and ZmMYB95-2 transgenic lines; 4) target genes, interaction proteins, gene networks of ZmMYB95-1 and ZmMYB95-2. This project has special implications in plant nutrition, genetics, and ecology and large potential for breeding application.