DataSheet1_Identification of DIR1-Dependant Cellular Responses in Guard Cell Systemic Acquired Resistance.PDF

After localized invasion by bacterial pathogens, systemic acquired resistance (SAR) is induced in uninfected plant tissues, resulting in enhanced defense against a broad range of pathogens. Although SAR requires mobilization of signaling molecules via the plant vasculature, the specific molecular mechanisms remain elusive. The lipid transfer protein defective in induced resistance 1 (DIR1) was identified in Arabidopsis thaliana by screening for mutants that were defective in SAR. Here, we demonstrate that stomatal response to pathogens is altered in systemic leaves by SAR, and this guard cell SAR defense requires DIR1. Using a multi-omics approach, we have determined potential SAR signaling mechanisms specific for guard cells in systemic leaves by profiling metabolite, lipid, and protein differences between guard cells in the wild type and dir1-1 mutant during SAR. We identified two long-chain 18 C and 22 C fatty acids and two 16 C wax esters as putative SAR-related molecules dependent on DIR1. Proteins and metabolites related to amino acid biosynthesis and response to stimulus were also changed in guard cells of dir1-1 compared to the wild type. Identification of guard cell-specific SAR-related molecules may lead to new avenues of genetic modification/molecular breeding for disease-resistant plants.

当植物遭受细菌病原体局部侵染后，未被侵染的植物组织会诱导产生系统获得性抗性（systemic acquired resistance, SAR），进而增强对多种病原体的防御能力。尽管SAR需通过植物维管束转运信号分子，但其具体分子机制仍未阐明。研究人员通过筛选SAR缺陷突变体，在拟南芥（Arabidopsis thaliana）中鉴定出诱导抗性缺陷脂质转运蛋白1（lipid transfer protein defective in induced resistance 1, DIR1）。本研究证实，SAR可改变系统叶片对病原体的气孔响应，且该保卫细胞介导的SAR防御过程依赖于DIR1。我们采用多组学策略，对SAR过程中野生型与dir1-1突变体保卫细胞的代谢物、脂质和蛋白质差异进行分析，解析了系统叶片保卫细胞特异性的潜在SAR信号机制。本研究鉴定出两种依赖DIR1的SAR相关候选分子：长链18碳脂肪酸、22碳脂肪酸，以及两种16碳蜡酯。与野生型相比，dir1-1突变体保卫细胞中与氨基酸生物合成及刺激响应相关的蛋白质和代谢物亦发生显著变化。鉴定保卫细胞特异性SAR相关分子，可为抗病植物的基因修饰/分子育种开辟全新途径。