Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, China.
Chongqing Academy of Agriculture Sciences, Chongqing, China.
Mol Plant Pathol. 2023 Dec;24(12):1467-1479. doi: 10.1111/mpp.13381. Epub 2023 Jul 24.
Plants have the ability to recognize the essential chitin molecule present in the fungal cell wall, which stimulates the immune response. Phytopathogenic fungi have developed various strategies to inhibit the chitin-triggered immune response. Here, we identified a chitin deacetylase of Puccinia striiformis f. sp. tritici (Pst), known as PsCDA2, that was induced during the initial invasion of wheat and acted as an inhibitor of plant cell death. Knockdown of PsCDA2 in wheat enhanced its resistance against Pst, highlighting the significance of PsCDA2 in the host-pathogen interaction. Moreover, PsCDA2 can protect Pst urediniospores from being damaged by host chitinase in vitro. PsCDA2 also suppressed the basal chitin-induced plant immune response, including the accumulation of callose and the expression of defence genes. Overall, our results demonstrate that Pst secretes PsCDA2 as a chitin deacetylase involved in establishing infection and modifying the acetyl group to prevent the breakdown of chitin in the cell wall by host endogenous chitinases. Our research unveils a mechanism by which the fungus suppresses plant immunity, further contributing to the understanding of wheat stripe rust control. This information could have significant implications for the development of suitable strategies for protecting crops against the devastating effects of this disease.
植物具有识别真菌细胞壁中存在的重要几丁质分子的能力，这会刺激免疫反应。植物病原真菌已经开发出各种策略来抑制几丁质触发的免疫反应。在这里，我们鉴定了小麦条锈菌（Puccinia striiformis f. sp. tritici）中的一种几丁质脱乙酰酶（PstCDA2），它在小麦的初始侵染过程中被诱导表达，并作为植物细胞死亡的抑制剂发挥作用。在小麦中敲低 PsCDA2 增强了其对 Pst 的抗性，凸显了 PsCDA2 在宿主-病原体相互作用中的重要性。此外，PsCDA2 可以保护 Pst 夏孢子免受宿主几丁酶在体外的破坏。PsCDA2 还抑制了基础几丁质诱导的植物免疫反应，包括几丁质酶诱导的胼胝质积累和防御基因的表达。总体而言，我们的研究结果表明，Pst 分泌 PsCDA2 作为一种几丁质脱乙酰酶，参与建立侵染并修饰乙酰基，以防止宿主内源性几丁酶对细胞壁中几丁质的分解。我们的研究揭示了真菌抑制植物免疫的一种机制，这进一步有助于理解小麦条锈病的防治。这些信息可能对开发保护作物免受这种疾病破坏性影响的合适策略具有重要意义。
