Whole genome sequence, CAZyme repertoire and sugar metabolic model of the phytopathogenic fungus Kretzschmaria zonata GFP 132.

Kretzschmaria zonata is an ascomycete fungus known as a significant plant pathogen that causes serious damage to teak plantations, but little is known about its genomic and metabolic features. Studies suggest this fungus is an interesting source of cell wall degrading enzymes. This study evaluated the genome and the diversity of genes encoding carbohydrate-active enzymes (CAZymes) of Kretzschmaria zonata GFP 132. The fungal ability to grow on different carbohydrates and its sugar metabolic network were also investigated. The findings were compared with other fungi, taxonomically close, phytopathogens or fungi known as good producers of plant cell wall degrading enzymes (CWDE). The assembled genome corresponding to 30.15 Mbp and 12,135 protein-coding genes, had approximately 5% of total protein-coding genes as putative CAZymes. In general, the closely related fungi, K. deusta, Hypoxylon submonticulosum, and Xylaria cf. heliscus exhibited a similar CAZymes profile. When compared with other phytopathogenic fungi, the variation in the CAZyme profile suggests that it does not accompany the similar species' lifestyle. Curiously, the repertoire of genes encoding CDWE was similar to Aspergillus niger, an Eurotiomycete, and different from Trichoderma reesei which is Sordariomycete like K. zonata. Based on genome, K. zonata possesses a complete sugar metabolic network, except for an absent gene in the galacturonic acid metabolic pathway. This is consistent with the inability of the fungus to grow in galacturonic acid as the sole carbon source. Finally, K. zonata was able to assimilate a wide range of mono and polysaccharides as carbon source, which opens perspectives for new studies to obtain new enzymes required to increase the efficiency of existing biotechnological industrial processes.