DataSheet_1_Chitin-induced systemic disease resistance in rice requires both OsCERK1 and OsCEBiP and is mediated via perturbation of cell-wall biogenesis in leaves.xlsx

Chitin is a well-known elicitor of disease resistance and its recognition by plants is crucial to perceive fungal infections. Chitin can induce both a local immune response and a systemic disease resistance when provided as a supplement in soils. Unlike local immune responses, it is poorly explored how chitin-induced systemic disease resistance is developed. In this study, we report the systemic induction of disease resistance against the fungal pathogen Bipolaris oryzae by chitin supplementation of soils in rice. The transcriptome analysis uncovered genes related to cell-wall biogenesis, cytokinin signaling, regulation of phosphorylation, and defence priming in the development of chitin-induced systemic response. Alterations of cell-wall composition were observed in leaves of rice plants grown in chitin-supplemented soils, and the disease resistance against B. oryzae was increased in rice leaves treated with a cellulose biosynthesis inhibitor. The disruption of genes for lysin motif (LysM)-containing chitin receptors, OsCERK1 (Chitin elicitor receptor kinase 1) and OsCEBiP (Chitin elicitor-binding protein), compromised chitin-induced systemic disease resistance against B. oryzae and differential expression of chitin-induced genes found in wild-type rice plants. These findings suggest that chitin-induced systemic disease resistance in rice is caused by a perturbation of cell-wall biogenesis in leaves through long-distance signalling after local recognition of chitins by OsCERK1 and OsCEBiP.

几丁质（chitin）是一类公认的抗病激发子，植物对其识别对于感知真菌侵染至关重要。将几丁质作为土壤添加剂施用时，其可同时诱导局部免疫响应与系统抗病性。与局部免疫响应不同，目前针对几丁质诱导的系统抗病性的形成机制研究仍较为匮乏。本研究中，我们报道了通过向土壤施加几丁质，可系统诱导水稻对真菌病原菌稻平脐蠕孢（Bipolaris oryzae）的抗病性。转录组分析揭示，在几丁质诱导的系统响应形成过程中，涉及细胞壁生物发生、细胞分裂素信号通路、磷酸化调控以及防御启动相关基因。在施加几丁质的土壤中生长的水稻叶片中，观测到细胞壁组成发生改变；同时，经纤维素生物合成抑制剂处理的水稻叶片，对稻平脐蠕孢的抗病性显著提升。含赖氨酸基序（Lysin motif, LysM）的几丁质受体基因OsCERK1（几丁质激发子受体激酶1，Chitin elicitor receptor kinase 1）与OsCEBiP（几丁质激发子结合蛋白，Chitin elicitor-binding protein）的功能缺失，会削弱水稻对稻平脐蠕孢的几丁质诱导系统抗病性，同时阻断野生型水稻中几丁质诱导基因的差异表达。上述研究结果表明，水稻中的几丁质诱导系统抗病性，是通过OsCERK1与OsCEBiP在局部识别几丁质后，经长距离信号传导，引发叶片细胞壁生物发生紊乱所介导的。