College of Plant Protection, China Agricultural University, Beijing, 100193, China.
College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China.
J Integr Plant Biol. 2022 Jan;64(1):183-201. doi: 10.1111/jipb.13194.
Phytophthora capsici is one of the most harmful pathogens in agriculture, which threatens the safe production of multiple crops and causes serious economic losses worldwide. Here, we identified a P. capsici expansin-like protein, PcEXLX1, by liquid chromatography-tandem mass spectrometry from Nicotiana benthamiana apoplastic fluid infected with P. capsici. Clustered regularly interspaced short palindromic repeats/crispr associated protein 9 (CRISPR/Cas9)-mediated PcEXLX1 knockout mutants exhibited significantly enhanced virulence, while the overexpression of PcEXLX1 impaired the virulence. Prokaryotically expressed PcEXLX1 activated multiple plant immune responses, which were BRI1-associated kinase 1 (BAK1)- and suppressor of BIR1-1 (SOBIR1)-dependent. Furthermore, overexpression of PcEXLX1 homologs in N. benthamiana could also increase plant resistance to P. capsici. A G-type lectin receptor-like kinase from N. benthamiana, expansin-regulating kinase 1 (ERK1), was shown to regulate the perception of PcEXLX1 and positively mediate the plant resistance to P. capsici. These results reveal that the expansin-like protein, PcEXLX1, is a novel apoplastic effector with plant immunity-inducing activity of oomycetes, perception of which is regulated by the receptor-like kinase, ERK1.
辣椒疫霉是农业中最具危害性的病原菌之一，它威胁着多种作物的安全生产并在全球范围内造成严重的经济损失。在这里，我们通过液相色谱-串联质谱法从感染辣椒疫霉的黄花烟质外体液中鉴定出一个辣椒疫霉扩展蛋白 PcEXLX1。CRISPR/Cas9 介导的 PcEXLX1 敲除突变体表现出明显增强的毒力，而过表达 PcEXLX1 则损害了毒力。原核表达的 PcEXLX1 激活了多种植物免疫反应，这些反应依赖于 BRASSINOSTEROID-INSENSITIVE1-ASSOCIATED KINASE 1 (BAK1) 和 SUPPRESSOR OF BIR1-1 (SOBIR1)。此外，在黄花烟中过表达 PcEXLX1 同源物也能提高植物对辣椒疫霉的抗性。从黄花烟中分离出的 G 型凝集素受体样激酶 expansin-regulating kinase 1 (ERK1) 被证明能调控 PcEXLX1 的感知，并正向介导植物对辣椒疫霉的抗性。这些结果表明，扩展蛋白样蛋白 PcEXLX1 是一种新型的质外体效应因子，具有卵菌的植物免疫诱导活性，其感知受受体样激酶 ERK1 调控。
