几丁质是真菌细胞壁的主要成分, 同时也是微生物相关分子模式(MAMP), 通过定位于细胞膜上的模式识别受体CERK1和LYK5识别, 激发植物的先天防御反应。该研究克隆了CERK1的胞内激酶域, 在酵母文库中筛选到1个分子伴侣HSP1与CERK1胞内域互作。通过CRISPR-Cas介导的基因编辑技术, 我们在野生型拟南芥(Arabidopsis thaliana) Col-0中敲除HSP1基因, 获得hsp1 v63删除突变体。使用几丁质处理Col-0和hsp1 v63删除突变体后发现, 下游防御相关基因的表达及丝裂原活化蛋白激酶磷酸化通路受到抑制。此外, 我们还发现CERK1蛋白水平在hsp1 v63删除突变体中低于野生型, 并且该突变体中CERK1含量降低与内质网降解系统有关。以上结果表明, HSP1是几丁质激发防御反应通路中的1个关键基因。该研究揭示了分子伴侣调控膜受体蛋白含量对植物防御反应的重要意义, 为农作物广谱抗性遗传改良奠定了理论基础。

Chitin, a major component of the fungal cell wall, is a kind of typical microbe associated molecular pattern (MAMP) that is recognized by two plasma membrane located LysM receptors, CERK1 and LYK5, and trigger immune response in plants. In this study, the intracellular kinase domain of CERK1 was cloned and used to screen the yeast cDNA library, and identify its interaction with HSP1. Using CRISPR-Cas-mediated gene editing technology, we knocked out the HSP1 gene in wild-type Arabidopsis thaliana Col-0 and obtained hsp1 v63 deletion mutant. We showed that the expression of downstream defense-related genes and the phosphorylation pathway of mitogen-activated protein kinase were inhibited in the hsp1 v63 deletion mutant compared to the wild type Col-0. We also showed that the protein level of CERK1 in hsp1 v63 mutants was lower than that in the Col-0, and that reduced CERK1 levels in this mutant were associated with the endoplasmic reticulum degradation system. These results indicate that HSP1 is a key gene in the chitin-induced defense response pathway, thus revealing the important roles of molecular chaperone in regulating receptor protein level and improvement in crop resistance.