Rice blast disease, caused by the ascomycete fungus Magnaporthe oryzae, is one of the most important diseases in rice production. PAS (period circadian protein, aryl hydrocarbon receptor nuclear translocator protein, single-minded protein) domains are known to be involved in signal transduction pathways, but their functional roles have not been well studied in fungi. In this study, targeted gene deletion was carried out to investigate the functional roles of the PAS-containing gene MoPAS1 (MGG_02665) in M. oryzae. The deletion mutant ΔMopas1 exhibited easily wettable mycelia, reduced conidiation, and defects in appressorium formation and disease development compared to the wild type and complemented transformant. Exogenous cAMP restored appressorium formation in ΔMopas1, but the shape of the restored appressorium was irregular, indicating that MoPAS1 is involved in sensing the hydrophobic surface. To examine the expression and localization of MoPAS1 in M. oryzae during appressorium development and plant infection, we constructed a MoPAS1:GFP fusion construct. MoPAS1:GFP was observed in conidia and germ tubes at 0 and 2 h post-infection (hpi) on hydrophobic cover slips. By 8 hpi, most of the GFP signal was observed in the appressoria. During invasive growth in host cells, MoPAS1:GFP was found to be fully expressed in not only the appressoria but also invasive hyphae, suggesting that MoPAS may contribute to disease development in host cells. These results expand our knowledge of the roles of PAS-containing regulatory genes in the plant-pathogenic fungus M. oryzae.

稻瘟病是由子囊真菌Magnaporthe oryzae引起的，是水稻生产中最重要的疾病之一。PAS（p eriod昼夜蛋白，一个RYL烃受体核转蛋白，š英格尔头脑蛋白）结构域是已知的参与信号转导途径，但它们的功能性作用还没有在真菌中得到很好的研究。在这项研究中，进行有针对性的基因删除，以研究含PAS的基因MoPAS1（MGG_02665）在米曲霉中的功能。缺失突变体ΔMopas1与野生型和互补型转化体相比，其表现出易于润湿的菌丝体，减少的分生孢子，以及食欲形成和疾病发展方面的缺陷。外源性的cAMP恢复在附着胞的形成ΔMopas1，但恢复附着胞的形状不规则，这表明MoPAS1参与感测所述疏水表面。检查MoPAS1在米曲霉中的表达和定位在食堂发育和植物感染过程中，我们构建了MoPAS1：GFP融合构建体。MoPAS1：GFP在分生孢子和胚芽管中在感染后0和2 h（hpi）的疏水盖玻片上观察到。在8 hpi时，在附睾中观察到大多数GFP信号。在宿主细胞的侵袭性生长过程中，发现MoPAS1：GFP不仅在美感区而且在侵袭性菌丝中都充分表达，这表明MoPAS可能有助于宿主细胞内的疾病发展。这些结果扩展了我们对植物致病性真菌米曲霉中含PAS调控基因作用的认识。