IntroductionRice blast disease caused by Magnaporthe oryzae has long been the main cause of rice (Oryza sativa L.) yield reduction worldwide. The quinone external inhibitor pyraclostrobin is widely used as a fungicide to effectively control the spread of pathogenic fungi, including M. oryzae. However, M. oryzae can develop resistance through multiple levels of mutation, such as target protein cytb mutation G143A/S, leading to a decrease in the effectiveness of the biocide after a period of application. Therefore, uncovering the possible mutational mechanisms from multiple perspectives will further provide feasible targets for drug development.MethodsIn this work, we determined the gene expression changes in M. oryzae in response to pyraclostrobin stress and their relationship with DNA methylation by transcriptome and methylome.ResultsThe results showed that under pyraclostrobin treatment, endoplasmic reticulum (ER)-associated and ubiquitin-mediated proteolysis were enhanced, suggesting that more aberrant proteins may be generated that need to be cleared. DNA replication and repair processes were inhibited. Glutathione metabolism was enhanced, while lipid metabolism was impaired. The number of alternative splicing events increased. These changes may be related to the elevated methylation levels of cytosine and adenine in gene bodies. Both hypermethylation and hypomethylation of differentially methylated genes (DMGs) mainly occurred in exons and promoters. Some DMGs and differentially expressed genes (DEGs) were annotated to the same pathways by GO and KEGG, including protein processing in the ER, ubiquitin-mediated proteolysis, RNA transport and glutathione metabolism, suggesting that pyraclostrobin may affect gene expression by altering the methylation patterns of cytosine and adenine.DiscussionOur results revealed that 5mC and 6mA in the gene body are associated with gene expression and contribute to adversity adaptation in M. oryzae. This enriched the understanding for potential mechanism of quinone inhibitor resistance, which will facilitate the development of feasible strategies for maintaining the high efficacy of this kind of fungicide.

转录因子在稻瘟病菌(Magnaporthe grisea)的生长发育、逆境适应以及致病性中发挥着重要作用.为明确类SRRM1转录因子调控的pre-mRNA剪接与稻瘟病菌生长发育和逆境适应的关系,采用以基因重组原理为基础的基因定点敲除技术获取类SRRM1基因缺失菌株,并分析营养生长及逆境适应.结果表明,本研究成功构建敲除载体并敲除了稻瘟病菌Y34菌株中的类SRRM1基因,获得基因缺失突变体.稻瘟病菌中类SRRM1基因缺失未明显影响其营养生长,但对刚果红、十二烷基硫酸钠、山梨醇、NaCl及杀菌剂吡唑醚菌酯逆境胁迫敏感,表现为抗逆性减弱.类SRRM1在稻瘟病菌逆境适应过程中发挥重要作用.

[目的]进一步了解分支点结合蛋白(branchpoint-bridging protein,BBP)在真菌中的生物学功能.[方法]利用多种生物信息学软件和网站对9种真菌[稻瘟病菌(Pyricularia oryzae)、酿酒酵母(Saccharomyces cerevisiae)、小麦全蚀病菌(Gaeumannomyces tritici)、粗糙脉孢菌(Neurospora crassa)、西瓜炭疽病菌(Colletotrichum orbiculare)、白僵菌(Beauveria bassiana)、尖孢镰刀菌(Fusarium oxysporum)、水稻恶苗病菌(Fusarium fujikuroi)和立枯丝核菌(Rhizoctonia solani)]的BBP进行预测分析,包括蛋白与基因的基本信息、理化性质、亚细胞定位、信号肽与跨膜螺旋结构、蛋白质空间构象及磷酸化位点与SUMO化位点,并构建系统进化树.[结果]BBP的分子量在50812.65～68306.99 Da,均为碱性不稳定的亲水性蛋白,存在于细胞核中,无信号肽及跨膜螺旋,磷酸化位点及占比相似,α螺旋是主要的二级结构,均具有SF1-HH、KH_dom和Znf_CCHC结构域,然而酿酒酵母ONH80283.1和立枯丝核菌CCO28600.1与其他真菌BBP相比在分子进化和空间构象上有较明显差异,且CCO28600.1的SUMO化位点较多.[结论]9种常见真菌中,酿酒酵母和立枯丝核菌的BBP结构比较特殊,BBP在稻瘟病菌、小麦全蚀病菌、粗糙脉孢菌、西瓜炭疽病菌、白僵菌、尖孢镰刀菌、水稻恶苗病菌中进化比较保守.

Alternative splicing is a common but complex posttranscriptional regulatory process in eukaryotes, through which multiple different transcripts are produced from a single pre-mRNA. An increasing number of studies have revealed that alternative splicing is widespread in fungi. Intron retention (IR) is considered the most prevalent splicing type due to the relatively short introns and long exons involved in this process. Alternative splicing is coordinated by a variety of factors, including genomic structure characteristics, TPP riboswitches, splicing factors and DNA methylation, and is involved in the regulation of growth and development, and the improvement of survivability and pathogenicity. Taken together, the results show that alternative splicing events are fungal evolutionary adaptations to changing external conditions.

稻瘟病菌是重要的模式致病真菌,该菌引发的稻瘟病也是全球水稻最严重的病害之一,因此对稻瘟病菌的研究具有重要的学术意义和实际价值.细胞周期受多层次、多因子共同调控,其相关控制蛋白在真菌的形态建成、发育分化、逆境适应及致病性等方面发挥重要作用.为明确稻瘟病菌细胞周期控制蛋白的生物信息学特性,利用多种生物信息学软件和网站对获得的3种细胞周期控制蛋白Cwf19、Cwf16和Cwf14的理化性质、亚细胞定位、分子进化、翻译后修饰、空间结构、互作蛋白等进行分析,探讨了其可能的作用机制,为进一步利用反向遗传学手段深入研究其生物学功能奠定基础.

具有不同遗传起源、独特功能及发育途径的种皮、胚乳与胚三部分组成的籽粒(种子)既是高等植物有性繁殖的重要器官,又是人类与动物的必需食物来源.在国内当前人口背景下,影响植物单产水平的籽粒建成问题值得关注.为此首先综述了植物籽粒建成的分子调控机制与源-库互作调控及相应的碳氮代谢机制,其次分析了籽粒建成机制与细胞分裂素的关联性,并阐释了细胞分裂素在植物籽粒建成中的研究利用价值.以期为今后深入研究高效安全的细胞分裂素类植物生长调节剂对植物籽粒建成的调控规律与机理,进而为在一定程度上合理应用该类植物生长调节剂并促进粮食产量增加提供参考.