Gene expression analysis of carbohydrate catabolism in Leucoagaricus gongylophorus LEU18496.

Abstract

Transcriptomic profiles were obtained by RNA-seq of Leucoagaricus gongylophorus growing on two carbon sources (glucose and cellulose) during different growth phases (exponential and stationary) with the aim of analyzing the variations in metabolism depending on the substrate and/or growth state. Principal component analysis (PCA) showed that 99.5% of the variation in gene expression is related to the substrate (PC1), clearly separating the experimental conditions, while the differences between growth phases are reflected in secondary components (PC2). Special attention was paid to the differential expression of CAZymes and FOLymes enzymes, demonstrating that, during the exponential phase of cellulose culture, there is an overexpression of enzymes from the GH6 and GH7 families (cellulases and cellobiosehydrolases), related to the degradation of complex polysaccharides such as cellulose. During the exponential phase of growth on glucose, expression of CAZymes enzymes ({beta}-glucosidase, pectinase and endo-{beta}-1,3-glucanase) was observed, in addition to an overexpression of laccases in this carbon source. Enrichment analysis identified significantly enriched functions related to carbohydrate catabolism and transport, evidence of the metabolic versatility of L. gongylophorus. High expression of the creA repressor factor was found in the presence of glucose, suggesting its regulatory role in the modulation of carbohydrate degradation. In the stationary phase, genes related to the response to oxidative stress and nutrient solubilization were activated under glucose, in contrast to cellulose, where the activation of secondary metabolism pathways was promoted, including the overexpression of trichodiene synthase.