Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China.
Key Laboratory of Microbial Resources, Ministry of Agriculture and Rural Affairs, 12 Zhongguancun South Street, Beijing, 100081, China.
Appl Microbiol Biotechnol. 2018 Aug;102(15):6627-6636. doi: 10.1007/s00253-018-9090-6. Epub 2018 May 30.
Fungal cells are surrounded by a tight cell wall to protect them from harmful environmental conditions and to resist lysis. The synthesis and assembly determine the shape, structure, and integrity of the cell wall during the process of mycelial growth and development. High temperature is an important abiotic stress, which affects the synthesis and assembly of cell walls. In the present study, the chitin and β-1,3-glucan concentrations in the cell wall of Pleurotus ostreatus mycelia were changed after high-temperature treatment. Significantly higher chitin and β-1,3-glucan concentrations were detected at 36 °C than those incubated at 28 °C. With the increased temperature, many aberrant chitin deposition patches occurred, and the distribution of chitin in the cell wall was uneven. Moreover, high temperature disrupts the cell wall integrity, and P. ostreatus mycelia became hypersensitive to cell wall-perturbing agents at 36 °C. The cell wall structure tended to shrink or distorted after high temperature. The cell walls were observed to be thicker and looser by using transmission electron microscopy. High temperature can decrease the mannose content in the cell wall and increase the relative cell wall porosity. According to infrared absorption spectrum, high temperature broke or decreased the glycosidic linkages. Finally, P. ostreatus mycelial cell wall was easily degraded by lysing enzymes after high-temperature treatment. In other words, the cell wall destruction caused by high temperature may be a breakthrough for P. ostreatus to be easily infected by Trichoderma.
真菌细胞被一层紧密的细胞壁包围，以保护它们免受有害的环境条件的影响，并抵抗裂解。在菌丝体生长和发育过程中，细胞壁的合成和组装决定了细胞壁的形状、结构和完整性。高温是一种重要的非生物胁迫，影响细胞壁的合成和组装。在本研究中，高温处理后，糙皮侧耳菌丝细胞壁中的几丁质和β-1,3-葡聚糖浓度发生了变化。在 36°C 下培养时，几丁质和β-1,3-葡聚糖的浓度明显高于在 28°C 下培养时的浓度。随着温度的升高，出现了许多异常的几丁质沉积斑点，几丁质在细胞壁中的分布不均匀。此外，高温破坏了细胞壁的完整性，在 36°C 时糙皮侧耳菌丝对细胞壁破坏剂变得更加敏感。细胞壁结构在高温后往往会收缩或变形。用透射电子显微镜观察到细胞壁变厚且疏松。高温会降低细胞壁中的甘露糖含量，增加相对细胞壁孔隙率。根据红外吸收光谱，高温破坏或减少了糖苷键。最后，高温处理后糙皮侧耳菌丝细胞壁容易被溶菌酶降解。换句话说，高温引起的细胞壁破坏可能是糙皮侧耳容易被木霉感染的一个突破口。
