中文摘要：DNA甲基化是重要的表观遗传修饰，依赖于DNA甲基转移酶(DMT)。但是，丝状真菌黄曲霉中没有可检测的甲基化，而一种DMT的同源物，dmtA，其作用不明确。本研究通过比较基因敲除、点突变、过表达及野生菌株，描述了dmtA在应对环境变化中的作用。结果表明dmtA基因在调节黄曲霉毒素的生物合成、黄曲霉对环境胁迫的适应及存活方面很重要，尽管它可能对DNA甲基化没有明显的作用。
外文摘要：DNA methylation is an important epigenetic modification that depends on DNA methyltransferases (DMT). However, the filamentous fungus Aspergillus flavus has no detectable methylation, and role of a DMT homologue, DmtA, is undefined. Here we describe the role of the dmtA gene responding to changes in the environment by comparing knockout, point mutation, over-expression and wild type strains. Deletion of dmtA differentially affected conidia development in a media-dependent fashion, which suggests that dmtA plays an important role in conidiation. Furthermore, ΔdmtA strains lost the capacity to form the resistant structure, sclerotia, and alleviated sensitivity to several stress conditions, such as high osmotic pressure, hypoxia, low water activity and a high calcium concentration. We also noticed that deletion of dmtA and mutation C377S in DmtA negatively affected aflatoxin production and down regulated the expression of some early (fas-1, pksA, nor-1), middle and late (nor-A, ver-1, avnA, omtB) genes in the aflatoxin biosynthetic cluster. Finally, we found that all tested strains showed a similar phenotype when treated with 5-azacytidine. Our results indicate that the dmtA gene is important in regulation of aflatoxin biosynthesis and for A. flavus to adapt to stressful environments and for survival, although it may hold no apparent function in DNA methylation.
外文关键词：Aflatoxin；DNA Methyltransferase homologue；Conidia development；Stress response；Sclerotia
作者：Zhi, QQ；Li, JY；Liu, QY；He, ZM
作者单位：Sun Yat Sen Univ
期刊名称：FUNGAL BIOLOGY
期刊影响因子：2.244
出版年份：2017
出版刊次：5
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