Abstract

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 ₂ ) is required for the expression of cellulase and xylanase genes.

• PoxCxrB dynamically regulated POX07277 expression.

中文翻译：

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磷脂酶 PLA 2 参与草酸青霉生产纤维素酶和木聚糖酶

摘要

磷脂酶在哺乳动物和植物的免疫和炎症反应中起着至关重要的作用；然而，对真菌中磷脂酶功能的了解是有限的。在这项研究中，我们研究了删除预测的磷脂酶基因对草酸青霉中纤维素酶和木聚糖酶产生以及形态表型的影响。十个预测的磷脂酶基因中的九个的单独缺失导致纤维素酶和木聚糖酶产生以及形态表型不同程度的改变。突变体ΔPOX07277损失了 22.5% 到 82.8% 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）和木聚糖酶的产生，而p-硝基苯基-β-吡喃葡萄糖苷酶的产量增加了 5.8-127.8 倍。POX07277 ( P. oxalicum基因 No. 07277) 被预测编码磷脂酶 A2，并被发现对草酸假单胞菌的孢子形成产生负面影响。比较转录组学和定量逆转录-PCR 分析表明，POX07277在微晶纤维素诱导下动态影响纤维素酶和木聚糖酶基因以及真菌孢子形成的调节基因的表达。POX07277是已知调节基因PoxCxrB（草酸杆菌中纤维素分解和木聚糖分解调节因子 B）的表达所必需的。)，它参与草酸假单胞菌中纤维素酶和木聚糖酶基因的表达。相反，POX07277表达受PoxCxrB调节。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的机制提供新的见解。

关键点

• 在草酸青霉中研究了磷脂酶的作用。

• POX07277 (PLA ₂ ) 是纤维素酶和木聚糖酶基因表达所必需的。

• PoxCxrB 动态调节 POX07277 表达。