Institute of Microbiology, Zhejiang University, Hangzhou, People's Republic of China.
Department of Entomology, University of Maryland, College Park, MD, USA.
Environ Microbiol. 2018 Mar;20(3):1158-1169. doi: 10.1111/1462-2920.14058. Epub 2018 Feb 28.
It is commonly observed that microorganisms subjected to a mild stress develop tolerance not only to higher doses of the same stress but also to other stresses - a phenomenon called cross protection. The mechanisms for cross protection have not been fully revealed. Here, we report that heat shock induced cross protection against UV, oxidative and osmotic/salt stress conditions in the cosmopolitan fungus Metarhizium robertsii. Similarly, oxidative and osmotic/salt stresses also induced cross protection against multiple other stresses. We found that oxidative and osmotic/salt stresses produce an accumulation of pyruvate that scavenges stress-induced reactive oxygen species and promotes fungal growth. Thus, stress-induced pyruvate accumulation contributes to cross protection. RNA-seq and qRT-PCR analyses showed that UV, osmotic/salt and oxidative stress conditions decrease the expression level of pyruvate consumption genes in the trichloroacetic acid cycle and fermentation pathways leading to pyruvate accumulation. Our work presents a novel mechanism for cross protection in microorganisms.
人们普遍观察到，微生物受到轻度胁迫后，不仅对更高剂量的同种胁迫产生耐受性，而且对其他胁迫也产生耐受性——这一现象称为交叉保护。交叉保护的机制尚未完全揭示。在这里，我们报告了在世界性真菌罗伯茨绿僵菌中，热休克诱导的对 UV、氧化和渗透/盐胁迫条件的交叉保护。同样，氧化和渗透/盐胁迫也诱导了对多种其他胁迫的交叉保护。我们发现氧化和渗透/盐胁迫会导致丙酮酸积累，从而清除应激诱导的活性氧并促进真菌生长。因此，应激诱导的丙酮酸积累有助于交叉保护。RNA-seq 和 qRT-PCR 分析表明，UV、渗透/盐和氧化胁迫条件会降低三羧酸循环和发酵途径中丙酮酸消耗基因的表达水平，导致丙酮酸积累。我们的工作为微生物中的交叉保护提供了一种新的机制。
