Key Laboratory of Biophysics of MOE, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, People's Republic of China.
National Engineering Research Centre of Edible Fungi, Key Laboratory of Applied Mycological Resources and Utilisation, Ministry of Agriculture, Institute of Edible Fungi, Shanghai Academy of Agriculture Sciences, Shanghai, People's Republic of China.
PLoS One. 2018 May 31;13(5):e0198404. doi: 10.1371/journal.pone.0198404. eCollection 2018.
Ganoderma lucidum is a medicinal mushroom that is well known for its ability to enhance human health, and products made from this fungus have been highly profitable. The substrate-degrading ability of G. lucidum could be related to its growth. CAZy proteins were more abundant in its genome than in the other white rot fungi models. Among these CAZy proteins, changes in lignocellulolytic enzymes during growth have not been well studied. Using genomic, transcriptomic and secretomic analyses, this study focuses on the lignocellulolytic enzymes of G. lucidum strain G0119 to determine which of these degradative enzymes contribute to its growth. From the genome sequencing data, genes belonging to CAZy protein families, especially genes involved in lignocellulose degradation, were investigated. The gene expression, protein abundance and enzymatic activity of lignocellulolytic enzymes in mycelia over a growth cycle were analysed. The overall expression cellulase was higher than that of hemicellulase and lignin-modifying enzymes, particularly during the development of fruiting bodies. The cellulase and hemicellulase abundances and activities increased after the fruiting bodies matured, when basidiospores were produced in massive quantities till the end of the growth cycle. Additionally, the protein abundances of the lignin-modifying enzymes and the expression of their corresponding genes, including laccases and lignin-degrading heme peroxidases, were highest when the mycelia fully spread in the compost bag. Type I cellobiohydrolase was observed to be the most abundant extracellular lignocellulolytic enzyme produced by the G. lucidum strain G0119. The AA2 family haem peroxidases were the dominant lignin-modifying enzyme expressed during the mycelial growth phase, and several laccases might play roles during the formation of the primordium. This study provides insight into the changes in the lignocellulose degradation ability of G. lucidum during its growth and will facilitate the discovery of new approaches to accelerate the growth of G. lucidum in culture.
灵芝是一种药用蘑菇，以增强人体健康的能力而闻名，其制成的产品利润丰厚。灵芝的基质降解能力可能与其生长有关。CAZy 蛋白在其基因组中的丰度高于其他白腐真菌模型。在这些 CAZy 蛋白中，生长过程中木质纤维素降解酶的变化尚未得到很好的研究。本研究利用基因组、转录组和分泌组分析，重点研究灵芝菌株 G0119 的木质纤维素降解酶，以确定哪些降解酶有助于其生长。从基因组测序数据中，研究了属于 CAZy 蛋白家族的基因，特别是涉及木质纤维素降解的基因。分析了整个生长周期中菌丝体中木质纤维素降解酶的基因表达、蛋白丰度和酶活性。总体纤维素酶表达高于半纤维素酶和木质素修饰酶，特别是在子实体发育过程中。当子实体成熟，大量产生担孢子直至生长周期结束时，纤维素酶和半纤维素酶的丰度和活性增加。此外，木质素修饰酶的蛋白丰度及其相应基因的表达，包括漆酶和木质素降解血红素过氧化物酶，在菌丝体在堆肥袋中完全扩散时最高。I 型纤维二糖水解酶被观察到是灵芝菌株 G0119 产生的最丰富的细胞外木质纤维素降解酶。AA2 家族血红素过氧化物酶是菌丝体生长阶段表达的主要木质素修饰酶，在原基形成过程中可能有几种漆酶发挥作用。本研究深入了解了灵芝在生长过程中木质纤维素降解能力的变化，将有助于发现加速灵芝在培养中生长的新方法。
