活性氧激活热激转录因子信号途径参与伽马氨基丁酸调节匍匐翦股颖耐热性机制研究

Creeping bentgrass, an important cold-season turfgrass, is widely used for the high-grade turf establishment, but its poor heat tolerance is a problem that needs to be solved urgently in the process of production and application. Our previous study found that the application of exogenous γ-aminobutyric acid (GABA) could significantly improve the heat tolerance of creeping bentgrass, and reactive oxygen (ROS) signaling and heat shock transcription factors (HSFs) may be involved in GABA-regulated heat tolerance in creeping bentgrass. Based on these information, the current study will explore GABA-induced the mechanism of heat tolerance through the comprehensive utilization of pharmacology, RNA-seq, qRT-PCR, western blot, and confocal laser scanning techniques: 1) GABA regulates the heat tolerance of creeping bentgrass through the activation of ROS and CDPK/MAPK signaling; 2) Key HSFs and HSFs-regulated downstream target genes induced by GABA will be selected; 3) GABA-induced ROS and CDPK/MAPK signaling involve in the regulation of HSFs and HSFs-regulated downstream target genes; 4) the function of GABA-regulated HSFs cloned from creeping bentgrass will be examined under heat stress. The study will contribute to better understanding the GABA-induced signal transduction pathway associated with heat tolerance in creeping bentgrass, determine the function of specific HSF gene, and provide theoretical basis and technical support that the scientific application of GABA could solve the problem of poor heat tolerance in cool-season turfgrass species.

匍匐翦股颖是建植高质量草坪的一种精细冷季型草，提高其耐热性是生产应用中急需解决的难题。我们初步研究发现，适宜浓度的外源伽马氨基丁酸（GABA）能够有效提高匍匐翦股颖耐热性，且活性氧（ROS）和热激转录因子（HSFs）信号通路可能参与其中。在此基础上，本项目将结合药理学实验、高通量RNA-seq测序、蛋白质免疫印迹、激光共聚焦显微等技术，主要研究：（1）GABA通过激活ROS和CDPK/MAPK信号参与调节匍匐翦股颖耐热性；（2）筛选GABA诱导的HSFs基因及其调控的下游靶基因；（3）GABA诱导的ROS和CDPK/MAPK信号参与调控HSFs及其靶基因；（4）GABA激活的特定匍匐翦股颖HSFs基因耐热性功能分析。以期探明GABA调控匍匐翦股颖耐热性的信号转导通路，阐释特定HSFs基因的功能，为解决冷季型草种耐热性差的难题提供理论和技术支持。

匍匐翦股颖是建植高质量草坪的一种精细冷季型草，提高其耐热性是生产应用中急需解决的难题。我们的研究发现，适宜浓度的外源伽马氨基丁酸（GABA）能够有效提高匍匐翦股颖耐热性，而降低内源GABA的含量则能显著消弱匍匐翦股颖的耐热性。通过转录组和小RNA（microRNA）分析发现，热胁迫下外源GABA能诱导大量差异基因及miRNA的表达，提高热激转录因子通路（HSFs pathway）、碳水化合物代谢及氨基酸转运和代谢等是GABA诱导植物耐热性的重要机制。采用荧光定量PCR及蛋白质免疫印迹进一步分析发现，热胁迫下GABA能显著上调热激转录因子（HSFA-6a、HSFA-2c和HSFB-2b）、热激蛋白基因（HSP17.8、HSP26.7、HSP70和HSP90.1-b1）和抗坏血酸过氧化物酶基因（APX3）的表达，而降低内源GABA的合成则显著降低了热诱导的这些基因的表达。此外，GABA也能显著提高热胁迫下HSP70、HSP90和HSP101的积累。这些结果进一步表明GABA参与调节热激转录因子通路从而提高匍匐翦股颖耐热性。本项目研究阐释了GABA调节热激转录通路提高匍匐翦股颖的耐热机制，为解决冷季型草种耐热性差的难题提供理论和技术支持。受本项目资助，以第一作者或通讯作者发表SCI收录论文7篇和中文核心期刊论文1篇（均为第一标柱）；以第一发明人获2项国家发明专利和10项实用新型专利。