State Key Laboratory of Crop Stress Biology for Arid Areas, College of Life Sciences, Northwest A&F University, Yangling, 712100, Shaanxi, China.
World J Microbiol Biotechnol. 2012 Jun;28(6):2331-9. doi: 10.1007/s11274-012-1040-3. Epub 2012 Mar 24.
The fungus Puccinia striiformis f. sp. tritici, the causal agent of wheat stripe rust, is an obligate biotrophic basidiomycete. Urediniospores are the most common spore type involved in the epidemiology of this disease. Tip growth of germ tubes of germinated urediniospores is a key step during infection of wheat, but few studies have investigated it so far. Recent research has found that actin is closely associated with hyphal tip growth. In this study, we have cloned and obtained the full-length actin cDNA from P. striiformis f. sp. tritici and characterized its expression. Furthermore, actin filament (F-actin) patterns were visualized microscopically during germ tube formation. The most conspicuous actin-containing structures were actin patches. They were mainly concentrated near the hyphal tip and scattered throughout the cortex. By using cytochalasin B, we observed that depolymerization of F-actin greatly reduced the germination rate of urediniospores and disrupted the transport of vesicles to the germ tube tip, indicating that F-actin played a key role in the tip growth of P. striiformis f. sp. tritici. This work helps us to understand the tip growth mechanism of P. striiformis f. sp. tritici, and may provide a theoretical framework for designing novel pesticides.
小麦条锈菌的病原菌条锈菌夏孢子是一种专性活体营养担子菌。夏孢子是该病害流行中最常见的孢子类型。萌发夏孢子的芽管尖端生长是小麦感染的关键步骤，但迄今为止，对此研究甚少。最近的研究发现，肌动蛋白与菌丝尖端生长密切相关。本研究从条锈菌夏孢子中克隆并获得了全长肌动蛋白 cDNA，并对其表达进行了分析。此外，还通过显微镜观察到了在芽管形成过程中肌动蛋白丝（F-肌动蛋白）的模式。最明显的含肌动蛋白结构是肌动蛋白斑。它们主要集中在菌丝尖端附近，并散布在皮层中。通过使用细胞松弛素 B，我们观察到 F-肌动蛋白的解聚大大降低了夏孢子的萌发率，并破坏了囊泡向芽管尖端的运输，表明 F-肌动蛋白在条锈菌夏孢子的尖端生长中起着关键作用。这项工作有助于我们了解条锈菌夏孢子的尖端生长机制，并可能为设计新型农药提供理论框架。
