Expression of a serine protease gene prC is up-regulated by oxidative stress in the fungus Clonostachys rosea: implications for fungal survival.
Expression of a serine protease gene prC is up-regulated by oxidative stress in the fungus Clonostachys rosea: implications for fungal survival.
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DOI：
10.1371/journal.pone.0013386
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发表时间：
2010-10-14
期刊：
影响因子：
3.7
通讯作者：
Zhang KQ
中科院分区：
文献类型：
--
作者：
Zou CG;Xu YF;Liu WJ;Zhou W;Tao N;Tu HH;Huang XW;Yang JK;Zhang KQ
土壤真菌面临着多种环境胁迫，如紫外线、高温和重金属。通过转录调控来适应基因表达是真菌响应环境胁迫的关键机制。在酿酒酵母中，转录因子 Msn2/4 通过与应激反应元件结合来诱导应激介导的基因表达。先前的研究表明，真菌中胞外蛋白酶的表达因热休克而上调。然而，热休克调节这些细胞外蛋白酶的生理意义仍不清楚。食线虫真菌Clonostachysrosea在线虫感染过程中可以分泌一种胞外丝氨酸蛋白酶PrC。由于prC的启动子具有三个拷贝的应激反应元件，我们研究了环境应激对prC表达的影响。我们的结果表明，氧化剂（H2O2 或甲萘醌）和热休克很可能通过应激反应元件上调 prC 的表达。氧化处理或热休克后，在线虫角质层存在的情况下，野生型菌株的分生孢子萌发率显着高于prC突变株。有趣的是，线虫角质层的添加显着减弱了野生型菌株中由氧化剂和热休克诱导的活性氧（ROS）的产生，但在prC突变菌株中则不然。此外，线虫角质层的低分子量（<3 kD）降解产物抑制了氧化剂和热休克诱导的分生孢子萌发的抑制作用。这些结果表明 PrC 在玫瑰花的氧化应激中发挥保护作用。 PrC 降解线虫角质层产生降解产物，进而通过清除 ROS 提供针对氧化应激的保护作用。我们的研究揭示了真菌适应环境压力的新策略。
Soil fungi face a variety of environmental stresses such as UV light, high temperature, and heavy metals. Adaptation of gene expression through transcriptional regulation is a key mechanism in fungal response to environmental stress. In Saccharomyces cerevisiae, the transcription factors Msn2/4 induce stress-mediated gene expression by binding to the stress response element. Previous studies have demonstrated that the expression of extracellular proteases is up-regulated in response to heat shock in fungi. However, the physiological significance of regulation of these extracellular proteases by heat shock remains unclear. The nematophagous fungus Clonostachys rosea can secret an extracellular serine protease PrC during the infection of nematodes. Since the promoter of prC has three copies of the stress response element, we investigated the effect of environmental stress on the expression of prC. Our results demonstrated that the expression of prC was up-regulated by oxidants (H2O2 or menadione) and heat shock, most likely through the stress response element. After oxidant treatment or heat shock, the germination of conidia in the wild type strain was significantly higher than that in the prC mutant strain in the presence of nematode cuticle. Interestingly, the addition of nematode cuticle significantly attenuated the production of reactive oxygen species (ROS) induced by oxidants and heat shock in the wild type strain, but not in prC mutant strain. Moreover, low molecule weight (<3 kD) degradation products of nematode cuticle suppressed the inhibitory effect of conidial germination induced by oxidants and heat shock. These results indicate that PrC plays a protective role in oxidative stress in C. rosea. PrC degrades the nematode cuticle to produce degradation products, which in turn offer a protective effect against oxidative stress by scavenging ROS. Our study reveals a novel strategy for fungi to adapt to environmental stress.