Department of Agricultural Biotechnology, Center for Fungal Genetic Resources, and Center for Fungal Pathogenesis, Plant Genomics and Breeding Institute, and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, Korea.
Environ Microbiol. 2015 Apr;17(4):1425-43. doi: 10.1111/1462-2920.12633. Epub 2014 Dec 11.
Regulatory roles of the basic leucine zipper (bZIP) transcription factors (TFs) in fungi have been identified in diverse cellular processes such as development, nutrient utilization and various stress responses. In this study, the 22 Magnaporthe oryzae genes encoding bZIP TFs were systematically characterized. Phylogenetic analysis of fungal bZIP TFs revealed that seven MobZIPs are Magnaporthe-specific, while others belongs to 15 clades of orthologous Ascomycota genes. Expression patterns of MobZIPs under various conditions showed that they are highly stress responsive. We generated deletion mutants for 13 MobZIPs: nine with orthologues in other fungal species and four Magnaporthe-specific ones. Seven of them exhibited defects in mycelial growth, development and/or pathogenicity. Consistent with the conserved functions of the orthologues, MobZIP22 and MobZIP13 played a role in sulfur metabolism and iron homeostasis respectively. Along with MobZIP22 and MobZIP13, one Magnaporthe-specific gene, MobZIP11 is essential for pathogenicity in a reactive oxygen species-dependent manner. Taken together, our results will contribute to understanding the regulatory mechanisms of the bZIP TF gene family in fungal development, adaptation to environmental stresses and pathogenicity in the rice blast fungus.
真菌中碱性亮氨酸拉链（bZIP）转录因子（TF）的调控作用已在发育、营养利用和各种应激反应等多种细胞过程中得到鉴定。在这项研究中，系统地研究了编码 bZIP TF 的 22 个稻瘟病菌基因。真菌 bZIP TF 的系统发育分析表明，七个 MobZIP 是稻瘟病菌特有的，而其他的则属于同源子囊菌的 15 个分支。在各种条件下 MobZIPs 的表达模式表明它们对胁迫高度敏感。我们生成了 13 个 MobZIP 的缺失突变体：其中 9 个与其他真菌物种的同源物有相似的功能，另外 4 个是稻瘟病菌特有的。其中 7 个在菌丝生长、发育和/或致病性方面表现出缺陷。与同源物的保守功能一致，MobZIP22 和 MobZIP13 分别在硫代谢和铁稳态中发挥作用。与 MobZIP22 和 MobZIP13 一起，一个稻瘟病菌特有的基因 MobZIP11 以依赖活性氧的方式对致病性至关重要。总之，我们的结果将有助于理解 bZIP TF 基因家族在真菌发育、适应环境胁迫和稻瘟病菌致病性中的调控机制。
