Zhang Guosheng, Zheng Yaqing, Ma Yuxin, Yang Le, Xie Meihua, Zhou Duanxu, Niu Xuemei, Zhang Ke-Qin, Yang Jinkui
State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China.
School of Life Sciences, Yunnan University, Kunming, China.
Front Microbiol. 2019 Aug 20;10:1917. doi: 10.3389/fmicb.2019.01917. eCollection 2019.
The velvet family proteins VosA and VelB are involved in growth regulation and differentiation in the model fungus and other filamentous fungi. In this study, the orthologs of VosA and VelB, AoVosA, and AoVelB, respectively, were characterized in the nematode-trapping fungus , which captures nematodes by producing trapping devices (traps). Deletion of the gene resulted in growth defects in different media, and the aerial hyphae from the Δ mutant lines were fewer in number and their colonies were less dense than those from the wild-type (WT) strain. The Δ mutants each displayed serious sporulation defects, and the transcripts of several sporulation-related genes (e.g., , , , and ) were significantly down-regulated compared to those from the WT strain. Furthermore, the Δ mutant strains became more sensitive to chemical reagents, including sodium dodecyl sulfate and HO. Importantly, the Δ mutants were unable to produce nematode-capturing traps. Similarly, extracellular proteolytic activity was also lower in the Δ mutants than in the WT strain. In contrast, the Δ mutants displayed no obvious differences from the WT strain in these phenotypic traits, whereas conidial germination was lower in the Δ mutants, which became more sensitive to heat shock stress. Our results demonstrate that the velvet protein AoVelB is essential for conidiation, trap formation, and pathogenicity in , while AoVosA plays a role in the regulation of conidial germination and heat shock stress.
天鹅绒家族蛋白VosA和VelB参与模式真菌及其他丝状真菌的生长调控和分化。在本研究中，分别对捕食线虫真菌中VosA和VelB的直系同源基因AoVosA和AoVelB进行了表征，该捕食线虫真菌通过产生捕捉装置（陷阱）来捕获线虫。基因缺失导致在不同培养基中生长缺陷，Δ突变株系的气生菌丝数量较少，其菌落比野生型（WT）菌株的菌落更稀疏。每个Δ突变体都表现出严重的产孢缺陷，与WT菌株相比，几个产孢相关基因（如、、、和）的转录本显著下调。此外，Δ突变菌株对包括十二烷基硫酸钠和HO在内的化学试剂变得更加敏感。重要的是，Δ突变体无法产生捕食线虫的陷阱。同样，Δ突变体中的细胞外蛋白水解活性也低于WT菌株。相比之下，Δ突变体在这些表型特征上与WT菌株没有明显差异，而Δ突变体中的分生孢子萌发率较低，且对热休克胁迫更敏感。我们的结果表明，天鹅绒蛋白AoVelB对的产孢、陷阱形成和致病性至关重要，而AoVosA在分生孢子萌发和热休克胁迫的调控中发挥作用。
