玉米bHLH类转录因子CS1响应低温的功能分析

Maize crop is important for food and feed production in china. Cold stress is one of the major factors to limit the yield and quality in maize. To solve these problems, we study the molecular mechanism of maize response to low temperature for breeding the cold resistant varieties. Using CRISPR technology, we generated two knock-out mutants of CS1, which conferred chilling sensitive phenotype at the seedling stage, and also displayed developmental defects in the later stage. These results demonstrate the important roles of CS1 in cold response and developmental process. RNA-Seq analysis showed 3946 differentially expressed genes (DEGs). After cold treatment, 1196 DEGs were regulated by CS1. GO analysis showed that these genes cover a wide range functions involved in abiotic stress, metabolic progress and catalytic activity. In this project, we will analyze CHIP-seq and RNA-seq data to identify the downstream target genes of CS1. Using biochemical and genetic approaches, we will reveal the mechanism of CS1-mediated cold response and developmental process. This study will elucidate the low temperature transcriptional regulatory network in maize and provide genetic information for the improvement of maize varieties.

玉米是我国重要的粮食作物和饲料作物，低温寒害是影响玉米品质和产量的重要因素。因此研究玉米响应低温的分子机制，培育耐寒品种，对提高我国玉米产量及品质具有重要意义。我们利用CRISPR技术获得bHLH类转录因子CS1的缺失突变体，在苗期具有冷敏感的表型，后期表现出生长发育缺陷表型。这些结果暗示CS1在低温信号及生长发育途径中发挥关键作用。通过RNA-seq数据分析，我们发现了3946个正常生长温度的差异表达基因及1196个低温处理下依赖于CS1的差异表达基因。这些基因涉及代谢途径、生长发育及逆境胁迫等重要途径。本项目拟结合CHIP-seq及RNA-seq数据，分析CS1下游靶基因，并通过生化方法及遗传分析验证他们在低温信号途径及生长发育过程中的作用。该研究可以揭示玉米低温信号途径的调控网络，同时为玉米的抗逆品种改良提供基因信息。

玉米是世界主要粮食作物，但由于气候变化，玉米产量的提高受到限制。作为关键影响因子，低温影响了玉米的产量和品质，但其分子机制目前尚不清楚。通过关联分析，我们发现耐冷表型与ZmCS1启动子中的单核苷酸多态性(SNPs)显著相关，ZmCS1编码玉米耐寒性的关键正向调节因子。此外，ZmCS1的表达水平受温度调节，ZmCS1启动子的等位基因变异影响其转录活性。ZmCS1被发现直接调节下游基因ZmCT1的表达。因此，ZmCS1介导一种转录调控，该调控通过调节下游靶基因表达正调节玉米抗寒性。因此，我们的发现为玉米耐冷性的遗传和分子基础提供了见解，并强调了利用转录调控策略改善玉米性状的潜力。