Department of Plant Pathology and Weed Research, Plant Protection Institute, Agricultural Research Organization, Volcani Institute, Rishon LeZion, Israel.
Phytopathology. 2023 Feb;113(2):277-285. doi: 10.1094/PHYTO-01-22-0035-R. Epub 2023 Feb 21.
The mechanisms underlying the ability of plants to differentiate between pathogens and commensals in their environment are currently unresolved. It has been suggested that spatiotemporal regulation of pattern-recognition receptor (PRR) content could be one of the components providing plants with the ability to distinguish between pathogens and nonpathogenic microbes. The LeEIX PRRs recognize xylanases derived from beneficial or commensal plant colonizers of species, including the xylanase known as EIX. Here, we investigated possible general roles of PRRs from the LeEIX locus in immunity and pathogen resistance in tomato. Mutating the inhibitory PRR LeEIX1, or overexpressing the activating PRR LeEIX2, resulted in resistance to a wide range of pathogens and increased basal and elicited immunity. LeEIX1 knockout caused increases in the expression level of several tested PRRs, including FLS2, as well as bacterial pathogen resistance coupled with an increase in flg22-mediated immunity. The wild tomato relative contains inactive LeEIX PRR variants. does not respond to elicitation with the LeEIX PRR ligand EIX. Given that EIX is derived from a mostly nonpathogenic microbe, the connection of its PRRs to disease resistance has not previously been investigated directly. Here, we observed that compared with cultivar M82, was more sensitive to several fungal and bacterial pathogens. Our results suggest that the LeEIX locus might determine resistance to fungal necrotrophs, whereas the resistance to biotrophs is effected in combination with a gene/quantitative trait locus not within the LeEIX locus.
目前，植物在其环境中区分病原体和共生体的能力的潜在机制尚未得到解决。有人提出，模式识别受体（PRR）含量的时空调控可能是植物区分病原体和非致病微生物的能力的组成部分之一。LeEIX PRR 识别来自有益或共生植物定殖者的木聚糖酶，包括已知的 EIX 木聚糖酶。在这里，我们研究了 LeEIX 基因座中的 PRR 在番茄免疫和病原体抗性中的可能普遍作用。突变抑制性 PRR LeEIX1 或过表达激活性 PRR LeEIX2 导致对广泛的病原体产生抗性，并增强了基础免疫和诱导免疫。LeEIX1 敲除导致几种测试的 PRR（包括 FLS2）的表达水平增加，同时还增加了对细菌病原体的抗性，以及 flg22 介导的免疫增强。野生番茄近缘种 含有非活性的 LeEIX PRR 变体。 对 LeEIX PRR 配体 EIX 的诱导没有反应。鉴于 EIX 源自大多数非致病性微生物，其 PRRs 与疾病抗性的联系以前并未直接研究过。在这里，我们观察到与 栽培品种 M82 相比， 对几种真菌和细菌病原体更敏感。我们的结果表明，LeEIX 基因座可能决定对真菌坏死生物的抗性，而对生物型的抗性则与不在 LeEIX 基因座内的基因/数量性状位点相结合。
