College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing 210095, China.
College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing 210095, China.
Int J Biol Macromol. 2024 Mar;261(Pt 2):129750. doi: 10.1016/j.ijbiomac.2024.129750. Epub 2024 Jan 28.
Bacillus spp. has been widely used as a biocontrol agent to control plant diseases. However, little is known about mechanisms of the protein MAMP secreted by Bacillus spp. Herein, our study reported a glycoside hydrolase family 30 (GH30) protein, BpXynC, produced by the biocontrol bacteria Bacillus paralicheniformis NMSW12, that can induce cell death in several plant species. The results revealed that the recombinant protein triggers cell death in Nicotiana benthamiana in a BAK1-dependent manner and elicits an early defense response, including ROS burst, activation of MAPK cascades, and upregulation of plant immunity marker genes. BpXynC was also found to be a glucuronoxylanase that exhibits hydrolysis activity on xlyan. Two mutants of BpXynC which lost the glucuronoxylanase activity still retained the elicitor activity. The qRT-PCR results of defense-related genes showed that BpXynC induces plant immunity responses via an SA-mediated pathway. BpXynC and its mutants could induce resistance in N. benthamiana against infection by Sclerotinia sclerotiorum and tobacco mosaic virus (TMV). Furthermore, BpXynC-treated tomato fruits exhibited strong resistance to the infection of Phytophthora capsica. Overall, our study revealed that GH30 protein BpXynC can induce plant immunity response as MAMP, which can be further applied as a biopesticide to control plant diseases.
芽孢杆菌已被广泛用作生物防治剂来控制植物病害。然而，人们对芽孢杆菌分泌的蛋白 MAMP 的机制知之甚少。本研究报道了由生防细菌地衣芽孢杆菌 NMSW12 产生的糖苷水解酶家族 30（GH30）蛋白 BpXynC，该蛋白能诱导几种植物物种的细胞死亡。结果表明，该重组蛋白以依赖于 BAK1 的方式在本氏烟中引发细胞死亡，并引发早期防御反应，包括 ROS 爆发、MAPK 级联的激活和植物免疫标记基因的上调。BpXynC 还是一种木聚糖酶，对木聚糖具有水解活性。丧失木聚糖酶活性的 BpXynC 两个突变体仍保留有激发子活性。防御相关基因的 qRT-PCR 结果表明，BpXynC 通过 SA 介导的途径诱导植物免疫反应。BpXynC 及其突变体能诱导本氏烟对核盘菌和烟草花叶病毒（TMV）的感染产生抗性。此外，用 BpXynC 处理的番茄果实对辣椒疫霉的感染表现出很强的抗性。总之，本研究揭示了 GH30 蛋白 BpXynC 可以作为 MAMP 诱导植物免疫反应，可进一步作为生物农药来控制植物病害。
