Polysaccharide metabolic pattern of Cytophagales and Flavobacteriales: a comprehensive genomics approach

Kuo-Jian Ma ^1,2 Ye Yonglian ² Yu-kang Li ^1,2 Geyi Fu ² Yuehong Wu ² Cong Sun ^3* Xue-wei Xu ^4*

• ¹ Ocean College, Zhejiang University, Hangzhou, Zhejiang Province, China
• ² Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, Zhejiang Province, China
• ³ Zhejiang Sci-Tech University, Hangzhou, Zhejiang, China
• ⁴ National Deep Sea Center (NDSC), Qingdao, China

As the most abundant and structurally diverse organic matter on earth, the complete metabolism of carbohydrates requires the involvement of different Carbohydrate-Active enZymes (CAZymes). Flavobacteriales and Cytophagales are two groups whose members specialized in polysaccharide metabolism, but research on their polysaccharide metabolic patterns based on overall CAZymes is scarce. In this study, we analyzed 702 filtered genomes of Flavobacteriales and Cytophagales and obtained 100,445 CAZymes, and according to their taxonomic statuses and living environments, explored the impact of taxonomic statuses, isolation sources, and environmental conditions on their potential polysaccharide metabolic patterns. The results indicated significant differences in CAZyme composition among different taxonomic statuses or environments. Compared to Flavobacteriales genomes, genomes of Cytophagales possess more abundant and diverse CAZymes, but have fewer unique CAZyme families. Genomes from different families vary greatly in the CAZyme family diversity and composition, but relatively small divergences were found from families in the same order. Furthermore, our findings indicated genomes from marine and tidal flats share more similarity in CAZyme family composition and diversity compared to terrestrial genomes. Extreme environments greatly constrain the type of the CAZyme family present there and certain CAZyme families are significantly lower than those in normal environments. Although significant differences were found among genomes from both different taxonomic statuses and environments, dimensionality reduction and clustering analysis based on CAZyme composition both indicate that evolutionary status is the main factor influencing the polysaccharide metabolic patterns of these strains. The correlations among CAZyme families indicating that the majority of CAZyme families are synergistically involved in polysaccharide metabolism. This study provides a comprehensive profile of CAZymes in Flavobacteriales and Cytophagales, highlighting the role of evolutionary status in shaping polysaccharide metabolic patterns and the prevalence of synergism among CAZyme families. These findings have implications for understanding microbial carbohydrate metabolism in different environments.