Polarized growth plays a key role in all domains of their biology, including morphogenesis and pathogenicity of filamentous fungi. However, little information is available about the determinants of polarized growth. The fungal Mep2, Pes1, and Cph1 proteins were identified to be involved in the dimorphic transition between yeast and hyphal forms in Candida albicans. In this study, evidence that the dimorphic fungal entomopathogen Ophiocordyceps sinensis Mep2, Pes1, and Cph1 proteins are involved in polarized growth is presented. OsMep2 was significantly upregulated at aerial hyphae and conidia germination stages. OsCph1 was significantly upregulated at aerial hyphae, conidia initiation, and conidia germination stages, and OsPes1 was significantly upregulated at the conidia germination stage. Deletions of OsMep2, OsCph1, and OsPes1 provoked defects in the polarized growth. The abilities of hyphal formation and the yields of blastospores and conidia for the ∆ OsMep2, ∆OsCph1, and ∆ OsPes1 mutants were significantly reduced. The conidia yields of the ΔOsMep2, ΔOsCph1, and ΔOsPes1 mutants were decreased by 69.17%, 60.90%, and 75.82%, respectively. Moreover, the pathogenicity of the ∆ OsMep2, ∆OsCph1, and ∆ OsPes1 mutants against Thitarodes xiaojinensis was significantly reduced. The mummification rate caused by wide type and ΔOsMep2, ΔOsCph1, and ΔOsPes1 mutants were 36.98% ± 8.52%, 0.31% ± 0.63%, 1.15% ± 1.57%, and 19.69% ± 5.6%, respectively. These results indicated that OsMep2, OsCph1, and OsPes1 are involved in the regulation of hyphal formation, sporulation, and pathogenicity of O. sinensis. This study provided a basis for the understanding of the fungal dimorphic development and improving the efficiency of artificial cultivation of O. sinensis.

中文翻译：

---

OsMep2、OsCph1 和 OsPes1 对二相性昆虫病原真菌冬虫夏草 (Ophiocordyceps sinensis) 形态发生和致病性的调节（肉座菌目：Ophiocordycipitaceae）

极化生长在其生物学的所有领域中发挥着关键作用，包括丝状真菌的形态发生和致病性。然而，关于两极增长的决定因素的信息很少。真菌 Mep2、Pes1 和 Cph1 蛋白被鉴定参与白色念珠菌中酵母和菌丝形式之间的二态性转变。在这项研究中，提出了二形性真菌昆虫病原体冬虫夏草 Mep2、Pes1 和 Cph1 蛋白参与极化生长的证据。 OsMep2 在气生菌丝和分生孢子萌发阶段显着上调。 OsCph1在气生菌丝、分生孢子起始和分生孢子萌发阶段显着上调，OsPes1在分生孢子萌发阶段显着上调。 OsMep2、OsCph1 和 OsPes1 的缺失会导致极化生长缺陷。 Δ OsMep2、ΔOsCph1 和 Δ OsPes1 突变体的菌丝形成能力以及芽生孢子和分生孢子的产量显着降低。 ΔOsMep2、ΔOsCph1和ΔOsPes1突变体的分生孢子产量分别降低了69.17%、60.90%和75.82%。此外，ΔOsMep2、ΔOsCph1 和ΔOsPes1 突变体对小金丝虱的致病性显着降低。宽型和ΔOsMep2、ΔOsCph1和ΔOsPes1突变体引起的木乃伊化率分别为36.98%±8.52%、0.31%±0.63%、1.15%±1.57%和19.69%±5.6%。这些结果表明，OsMep2、OsCph1 和 OsPes1 参与了中华 O. sinensis 菌丝形成、孢子形成和致病性的调节。该研究为认识冬虫夏草真菌二态性发育和提高冬虫夏草人工栽培效率提供了基础。