Beijing Key Laboratory of Environment Friendly Management on Fruit Diseases and Pests in North China, Institute of Plant and Environment Protection, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, China.
Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai 57100, Thailand.
Phytopathology. 2020 Oct;110(10):1727-1736. doi: 10.1094/PHYTO-04-20-0118-R. Epub 2020 Aug 27.
The genome encodes numerous glycoside hydrolases involved in organic matter degradation and conducive to pathogen infection, whereas their molecular mechanisms are still largely unknown. Here, we identified the glycoside hydrolase family 28 endopolygalacturonase LtEPG1 in and characterized its function in detail. LtEPG1 acts as a virulence factor during infection. Overexpression and silencing of in led to significantly increased and decreased lesion areas, respectively. Further, the high transcript level of during the infection process supported its virulence function. Polygalacturonase activity of LtEPG1 was substantiated by detecting its ability to degrade pectin. Furthermore, LtEPG1 functioned as microbe-associated molecular patterns during the infection process. Both transient expression of LtEPG1 in planta and infiltration of purified LtEPG1 triggered cell death in . Site-directed mutation of indicated that the enzymatic activity of LtEPG1 is independent from its elicitor activity. A protein kinase, KINβ1, was shown to interact in the yeast two-hybrid system with LtEPG1. This interaction was further confirmed in vitro using a pull-down assay. Our data indicate that LtEPG1 functions as a polygalacturonase and also serves as an elicitor with two independent mechanisms. Moreover, LtEPG1 may be able to manipulate host immune responses by regulating the KINβ1-mediated signal pathway and consequently promote its own successful infection and symptom development.
基因组编码了许多参与有机物降解和有利于病原体感染的糖苷水解酶，但其分子机制在很大程度上仍不清楚。在这里，我们鉴定了 中的糖苷水解酶家族 28 内切多聚半乳糖醛酸酶 LtEPG1，并详细描述了其功能。LtEPG1 在 感染过程中充当毒力因子。在 中过表达和沉默 导致病变面积显著增加和减少。此外，在感染过程中 的高转录水平支持其毒力功能。通过检测 LtEPG1 降解果胶的能力证实了多聚半乳糖醛酸酶活性。此外，LtEPG1 在感染过程中充当微生物相关分子模式。瞬时表达 LtEPG1 在植物体内和纯化 LtEPG1 的渗透都在 中引发细胞死亡。对 LtEPG1 的定点突变表明其酶活性与其激发子活性无关。蛋白激酶 KINβ1 在酵母双杂交系统中与 LtEPG1 相互作用。使用下拉测定进一步在体外证实了这种相互作用。我们的数据表明 LtEPG1 既作为多聚半乳糖醛酸酶，也作为具有两种独立机制的激发子发挥作用。此外，LtEPG1 可能通过调节 KINβ1 介导的信号通路来操纵宿主免疫反应，从而促进其自身成功的感染和症状发展。
