Wang Xiuna, Wu Fan, Liu Ling, Liu Xingzhong, Che Yongsheng, Keller Nancy P, Guo Liyun, Yin Wen-Bing
Department of Plant Pathology and the Ministry of Agriculture Key Laboratory for Plant Pathology, China Agricultural University, Beijing 100193, China; State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
Fungal Genet Biol. 2015 Aug;81:221-8. doi: 10.1016/j.fgb.2015.03.010. Epub 2015 Apr 4.
The bZIP transcription factors are conserved in all eukaryotes and play critical roles in organismal responses to environmental challenges. In filamentous fungi, several lines of evidence indicate that secondary metabolism (SM) is associated with oxidative stress mediated by bZIP proteins. Here we uncover a connection with a bZIP protein and oxidative stress induction of SM in the plant endophytic fungus Pestalotiopsis fici. A homology search of the P. fici genome with the bZIP protein RsmA, involved in SM and the oxidative stress response in Aspergillus nidulans, identified PfZipA. Deletion of PfzipA resulted in a strain that displayed resistant to the oxidative reagents tert-butylhydroperoxide (tBOOH), diamide, and menadione sodium bisulfite (MSB), but increased sensitivity to H2O2 as compared to wild type (WT). Secondary metabolite production presented a complex pattern dependent on PfzipA and oxidative reagents. Without oxidative treatment, the ΔPfzipA strain produced less isosulochrin and ficipyroneA than WT; addition of tBOOH further decreased production of iso-A82775C and pestaloficiol M in ΔPfzipA; diamide treatment resulted in equivalent production of isosulochrin and ficipyroneA in the two strains; MSB treatment further decreased production of RES1214-1 and iso-A82775C but increased pestaloficiol M production in the mutant; and H2O2 treatment resulted in enhanced production of isosulochrin, RES1214-1 and pestheic acid but decreased ficipyroneA and pestaloficiol M in ΔPfzipA compared to WT. Our results suggest that PfZipA regulation of SM is modified by oxidative stress pathways and provide insights into a possible role of PfZipA in mediating SM synthesis in the endophytic lifestyle of P. fici.
bZIP转录因子在所有真核生物中都很保守，在生物体应对环境挑战中发挥关键作用。在丝状真菌中，有几条证据表明次级代谢（SM）与bZIP蛋白介导的氧化应激有关。在这里，我们揭示了植物内生真菌榕树拟盘多毛孢中一种bZIP蛋白与SM氧化应激诱导之间的联系。用参与构巢曲霉SM和氧化应激反应的bZIP蛋白RsmA对榕树拟盘多毛孢基因组进行同源搜索，鉴定出PfZipA。PfzipA的缺失导致一个菌株对氧化试剂叔丁基过氧化氢（tBOOH）、二酰胺和亚硫酸氢钠甲萘醌（MSB）具有抗性，但与野生型（WT）相比，对H2O2的敏感性增加。次级代谢产物的产生呈现出一种依赖于PfzipA和氧化试剂的复杂模式。在没有氧化处理的情况下，ΔPfzipA菌株产生的异硫色菌素和ficipyroneA比WT少；添加tBOOH进一步降低了ΔPfzipA中异A82775C和拟盘多毛孢醇M的产量；二酰胺处理导致两种菌株中异硫色菌素和ficipyroneA的产量相当；MSB处理进一步降低了RES1214-1和异A82775C的产量，但增加了突变体中拟盘多毛孢醇M的产量；与WT相比，H2O2处理导致ΔPfzipA中异硫色菌素、RES1214-1和拟盘多毛孢酸的产量增加，但ficipyroneA和拟盘多毛孢醇M的产量降低。我们的结果表明，PfZipA对SM的调控受到氧化应激途径的影响，并为PfZipA在榕树拟盘多毛孢内生生活方式中介导SM合成的可能作用提供了见解。
