Li Shi-Huan, Gu Li-Sha, Qu Xiao-Yi, Zhang Ting, Li Cheng-Xi, Mai Rong-Ming, Liao Lu-Sheng, Zhang Feng-Fei, Luo Xue-Mei, Zhao Shuai, Feng Jia-Xun
State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Research Center for Microbial and Enzyme Engineering Technology, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, People's Republic of China.
Appl Microbiol Biotechnol. 2021 Jan;105(2):679-694. doi: 10.1007/s00253-020-11065-1. Epub 2021 Jan 4.
Phospholipases play vital roles in immune and inflammatory responses in mammals and plants; however, knowledge of phospholipase functions in fungi is limited. In this study, we investigated the effects of deleting predicted phospholipase genes on cellulase and xylanase production, and morphological phenotype, in Penicillium oxalicum. Individual deletion of nine of the ten predicted phospholipase genes resulted in alteration of cellulase and xylanase production, and the morphological phenotypes, to various degrees. The mutant ∆POX07277 lost 22.5 to 82.8% of cellulase (i.e., filter paper cellulase, carboxymethylcellulase, and p-nitrophenyl-β-cellobiosidase) and xylanase production, whereas p-nitrophenyl-β-glucopyranosidase production increased by 5.8-127.8 fold. POX07277 (P. oxalicum gene No. 07277) was predicted to encode phospholipase A2 and was found to negatively affect the sporulation of P. oxalicum. Comparative transcriptomic and quantitative reverse transcription-PCR analysis indicated that POX07277 dynamically affected the expression of cellulase and xylanase genes and the regulatory genes for fungal sporulation, under micro-crystalline cellulose induction. POX07277 was required for the expression of the known regulatory gene PoxCxrB (cellulolytic and xylanolytic regulator B in P. oxalicum), which is involved in cellulase and xylanase gene expression in P. oxalicum. Conversely, POX07277 expression was regulated by PoxCxrB. These findings will aid the understanding of phospholipase functions and provide novel insights into the mechanism of fungal cellulase and xylanase gene expression. KEY POINTS : • The roles of phospholipases were investigated in Penicillium oxalicum. • POX07277 (PLA) is required for the expression of cellulase and xylanase genes. • PoxCxrB dynamically regulated POX07277 expression.
磷脂酶在哺乳动物和植物的免疫及炎症反应中发挥着至关重要的作用；然而，关于磷脂酶在真菌中的功能的了解却很有限。在本研究中，我们调查了删除预测的磷脂酶基因对草酸青霉纤维素酶和木聚糖酶产量以及形态表型的影响。十个预测的磷脂酶基因中的九个被单独删除，导致纤维素酶和木聚糖酶产量以及形态表型在不同程度上发生改变。突变体∆POX07277的纤维素酶（即滤纸纤维素酶、羧甲基纤维素酶和对硝基苯基-β-纤维二糖酶）和木聚糖酶产量损失了22.5%至82.8%，而对硝基苯基-β-吡喃葡萄糖苷酶产量增加了5.8至127.8倍。POX07277（草酸青霉基因编号07277）被预测编码磷脂酶A2，并且被发现对草酸青霉的孢子形成有负面影响。比较转录组学和定量逆转录PCR分析表明，在微晶纤维素诱导下，POX07277动态影响纤维素酶和木聚糖酶基因以及真菌孢子形成调控基因的表达。POX07277是已知调控基因PoxCxrB（草酸青霉中的纤维素分解和木聚糖分解调节因子B）表达所必需的，该基因参与草酸青霉中纤维素酶和木聚糖酶基因的表达。相反，POX07277的表达受PoxCxrB调控。这些发现将有助于理解磷脂酶的功能，并为真菌纤维素酶和木聚糖酶基因表达机制提供新的见解。要点：• 在草酸青霉中研究了磷脂酶的作用。• POX07277（PLA）是纤维素酶和木聚糖酶基因表达所必需的。• PoxCxrB动态调节POX07277的表达。
