Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia.
Department of Biology, Faculty of Science and Mathematics, Universiti Pendidikan Sultan Idris, 35900, Tanjong Malim, Perak, Malaysia.
Microb Ecol. 2022 Feb;83(2):363-379. doi: 10.1007/s00248-021-01757-0. Epub 2021 Apr 22.
Rigidoporus microporus is the fungus accountable for the white root rot disease that is detrimental to the rubber tree, Hevea brasiliensis. The pathogenicity mechanism of R. microporus and the identity of the fungal proteins and metabolites involved during the infection process remain unclear. In this study, the protein and metabolite profiles of two R. microporus isolates, Segamat (SEG) and Ayer Molek (AM), were investigated during an in vitro interaction with H. brasiliensis. The isolates were used to inoculate H. brasiliensis clone RRIM 2025, and mycelia adhering to the roots of the plant were collected for analysis. Transmission electron microscope (TEM) images acquired confirms the hyphae attachment and colonization of the mycelia on the root of the H. brasiliensis clones after 4 days of inoculation. The protein samples were subjected to 2-DE analysis and analyzed using MALDI-ToF MS/MS, while the metabolites were extracted using methanol and analyzed using LC/MS-QTOF. Based on the differential analyses, upregulation of proteins that are essential for fungal evolution such as malate dehydrogenase, fructose 1,6-biphosphate aldolase, and glyceraldehyde-3-phosphate dehydrogenase hints an indirect role in fungal pathogenicity, while metabolomic analysis suggests an increase in acidic compounds which may lead to increased cell wall degrading enzyme activity. Bioinformatics analyses revealed that the carbohydrate and amino acid metabolisms were prominently affected in response to the fungal pathogenicity. In addition to that, other pathways that were significantly affected include "Protein Ubiquitination Pathway," Unfolded Protein Response," "HIFα Signaling," and "Sirtuin Signaling Pathway." The identification of responsive proteins and metabolites from this study promotes a better understanding of mechanisms underlying R. microporus pathogenesis and provides a list of potential biological markers for early recognition of the white root rot disease.
密孔菌是导致橡胶树（Hevea brasiliensis）白根腐烂病的罪魁祸首。密孔菌的致病性机制以及感染过程中涉及的真菌蛋白和代谢物的身份尚不清楚。在这项研究中，研究了两种密孔菌分离株（Segamat（SEG）和 Ayer Molek（AM））在与巴西橡胶树 RRIM 2025 体外相互作用过程中的蛋白质和代谢物谱。使用这些分离株接种巴西橡胶树克隆 RRIM 2025，并收集附着在植物根部的菌丝体进行分析。透射电子显微镜（TEM）图像的获取证实，接种后 4 天，菌丝附着在巴西橡胶树克隆的根部并定殖。将蛋白质样品进行 2-DE 分析，并使用 MALDI-ToF MS/MS 进行分析，而代谢物则使用甲醇提取，并使用 LC/MS-QTOF 进行分析。基于差异分析，上调了与真菌进化有关的必需蛋白，如苹果酸脱氢酶、果糖 1,6-二磷酸醛缩酶和甘油醛-3-磷酸脱氢酶，这暗示了其在真菌致病性中的间接作用，而代谢组学分析表明酸性化合物的增加可能导致细胞壁降解酶活性的增加。生物信息学分析表明，碳水化合物和氨基酸代谢在响应真菌致病性时受到显著影响。除此之外，其他受到显著影响的途径包括“蛋白泛素化途径”、“未折叠蛋白反应”、“HIFα 信号”和“Sirtuin 信号通路”。本研究中响应蛋白和代谢物的鉴定促进了对密孔菌发病机制的更好理解，并提供了一组潜在的生物标志物，用于早期识别白根腐烂病。
