Comparative Analysis of Herbaceous and Woody Cell Wall Digestibility by Pathogenic Fungi

• Published in: Molecules (Basel, Switzerland) Switzerland), 2021-11, Vol.26 (23), p.7220
• Main Authors: Dou, Yanhua, Yang, Yan, Mund, Nitesh Kumar, Wei, Yanping, Liu, Yisong, Wei, Linfang, Wang, Yifan, Du, Panpan, Zhou, Yunheng, Liesche, Johannes, Huang, Lili, Fang, Hao, Zhao, Chen, Li, Jisheng, Wei, Yahong, Chen, Shaolin
• Format: Article
• Language: English
• Subjects: apple tree branch; Biodiesel fuels; Biofuels; Biomass; Brassica napus; Brassica napus - microbiology; Brassica napus - physiology; Cell Wall - metabolism; Cell Wall - microbiology; Cell walls; Cellulases - metabolism; Cellulose; Cellulose - metabolism; Comparative analysis; Crop residues; Degradability; Digestibility; Emission analysis; Enzymatic activity; Enzyme activity; Enzymes; Field emission microscopy; Fruit trees; Fungal Proteins - metabolism; Fungi; Fungi - enzymology; Fungi - physiology; Genomic analysis; Hemicellulases; Hemicellulose; hemicelluloses; Host plants; Host-Pathogen Interactions; Hydrolysis; Lignin; Malus - microbiology; Malus - physiology; Pathogens; Peracetic acid; Plant biomass; Plant Diseases - microbiology; Polysaccharides - metabolism; Preferences; Pretreatment; Rapeseed; rapeseed straw; Scanning electron microscopy; Straw; Substrates; Trees; Triticum - microbiology; Triticum - physiology; Virulence; Wheat; wheat straw; Wood - microbiology; Wood - physiology
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules26237220

Fungal pathogens have evolved combinations of plant cell-wall-degrading enzymes (PCWDEs) to deconstruct host plant cell walls (PCWs). An understanding of this process is hoped to create a basis for improving plant biomass conversion efficiency into sustainable biofuels and bioproducts. Here, an approach integrating enzyme activity assay, biomass pretreatment, field emission scanning electron microscopy (FESEM), and genomic analysis of PCWDEs were applied to examine digestibility or degradability of selected woody and herbaceous biomass by pathogenic fungi. Preferred hydrolysis of apple tree branch, rapeseed straw, or wheat straw were observed by the apple-tree-specific pathogen , the rapeseed pathogen , and the wheat pathogen , respectively. Delignification by peracetic acid (PAA) pretreatment increased PCW digestibility, and the increase was generally more profound with non-host than host PCW substrates. Hemicellulase pretreatment slightly reduced or had no effect on hemicellulose content in the PCW substrates tested; however, the pretreatment significantly changed hydrolytic preferences of the selected pathogens, indicating a role of hemicellulose branching in PCW digestibility. Cellulose organization appears to also impact digestibility of host PCWs, as reflected by differences in cellulose microfibril organization in woody and herbaceous PCWs and variation in cellulose-binding domain organization in cellulases of pathogenic fungi, which is known to influence enzyme access to cellulose. Taken together, this study highlighted the importance of chemical structure of both hemicelluloses and cellulose in host PCW digestibility by fungal pathogens.