禾谷镰刀菌分泌蛋白的N端增强植物的广谱抗病性

小麦赤霉病是由禾谷镰刀菌引起的破坏性疾病。但是关于禾谷镰刀菌的致病分子武器知之甚少。

在本研究中，作者发现在小麦感染期间，禾谷镰刀菌中编码一种小的分泌蛋白 Fg02685的基因被上调。Fg02685的敲除突变降低了小麦穗中禾谷镰刀菌的生长发育。

在不依赖BAK1和SOBIR1的系统中，Fg02685或重组蛋白的瞬时表达导致植物细胞死亡。 作者进一步发现Fg02685通过增加胼胝质的沉积、活性氧 (ROS) 的积累和防御相关基因的表达来触发植物基础免疫。Fg02685信号肽是植物质外体积累和诱导细胞死亡所必需的，表明 Fg02685 是一种新型保守的病原相关分子模式。

此外，其同源物广泛分布于卵菌和真菌病原体中，并在烟草中诱导细胞死亡。 N末端的保守螺旋基序是诱导细胞死亡所必需的。此外，一种 32 个氨基酸的肽Fg02685N 末端肽 32 (FgNP32) 对于诱导植物中的氧化爆发、胼胝质沉积和丝裂原活化蛋白激酶信号激活至关重要。长期暴露于FgNP32增强了植物对镰刀菌和疫霉的抗性。

本研究通过应用植物免疫诱导剂增强作物的广谱抗病性，为作物病害的环境友好型控制策略提供了新的途径。

Fusarium head blight is a destructive disease caused byFusariumspecies. Little is known about the pathogenic molecular weapons ofFusarium graminearum. The gene encoding a small secreted protein, Fg02685, inF. graminearumwas found to be upregulated during wheat head infection. Knockout mutation of Fg02685 reduced the growth and development ofFusariumin wheat spikes. Transient expression of Fg02685 or recombinant protein led to plant cell death in a BAK1- and SOBIR1-independent system. Fg02685 was found to trigger plant basal immunity by increasing the deposition of callose, the accumulation of reactive oxygen species (ROS), and the expression of defence-related genes. The Fg02685 signal peptide was required for the plant's apoplast accumulation and induces cell death, indicating Fg02685 is a novel conserved pathogen-associated molecular pattern.Moreover, its homologues are widely distributed in oomycetes and fungal pathogens and induced cell death in tobacco. The conserved α-helical motif at the N-terminus was necessary for the induction of cell death. Moreover, a 32-amino-acid peptide, Fg02685 N-terminus peptide 32 (FgNP32), was essential for the induction of oxidative burst, callose deposition, and mitogen-activated protein kinase signal activation in plants. Prolonged exposure to FgNP32 enhanced the plant's resistance toFusariumandPhytophthora. This study provides new approaches for an environment-friendly control strategy for crop diseases by applying plant immune inducers to strengthen broad-spectrum disease resistance in crops.

该研究论文《The N-terminus of aFusarium graminearum-secreted protein enhances broad-spectrum disease resistance in plants》由四川农业大学魏育明团队发表在MPP。