Deoxynivalenol (DON) is an important trichothecene mycotoxin produced by the cereal pathogen Fusarium graminearum. DON is synthesized in organized endoplasmic reticulum structures called toxisomes. However, the mechanism for toxisome formation and the components of toxisomes are not yet fully understood. In a previous study, we found that myosin I (FgMyo1)‐actin cytoskeleton participated in toxisome formation. In the current study, we identified two new components of toxisomes, the actin capping proteins (CAPs) FgCapA and FgCapB. These two CAPs form a heterodimer in F. graminearum, and physically interact with FgMyo1 and Tri1. The deletion mutants ΔFgcapA and ΔFgcapB and the double deletion mutant ΔΔFgcapA/B dramatically reduced hyphal growth, asexual and sexual reproduction and endocytosis. More importantly, the deletion mutants markedly disrupted toxisome formation and DON production, and attenuated virulence in planta. Collectively, these results suggest that the actin CAPs are associated with toxisome formation and contribute to the virulence and development of F. graminearum.

中文翻译：

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覆盖蛋白调节禾谷镰刀菌中的真菌发育，DON-毒素形成和毒力。

脱氧雪腐烯酚（DON）是一种由谷物病原体禾谷镰刀菌（Fusarium graminearum）产生的重要的天花粉真菌毒素。DON在称为毒素的有组织内质网结构中合成。然而，关于毒素形成的机理和毒素的成分尚未完全了解。在先前的研究中，我们发现肌球蛋白I（FgMyo1）-肌动蛋白细胞骨架参与了毒素的形成。在当前的研究中，我们确定了毒素的两个新成分，肌动蛋白加帽蛋白（CAPs）FgCapA和FgCapB。这两个CAPs在禾谷镰刀菌中形成异二聚体，并与FgMyo1和Tri1发生物理相互作用。缺失突变体ΔFgcapA和ΔFgcapB和双缺失突变体ΔΔFgcapA / B大大减少了菌丝的生长，无性繁殖和有性繁殖以及内吞作用。更重要的是，缺失突变体显着破坏了毒素的形成和DON的产生，并减弱了植物体内的毒力。总体而言，这些结果表明肌动蛋白CAP与毒素的形成有关，并有助于禾本科镰刀菌的毒力和发育。