Metagenomic insights into the dynamic degradation of brown algal polysaccharides by kelp-associated microbiota

作者：Yi-Shuo Zhang, Yuqi Zhang, Xiang-Ming Zhao, Xiaolei Liu, Qi‐Long Qin, Ning-Hua Liu, Fei Xu, Xiu‐Lan Chen, Yu‐Zhong Zhang, Ping‐Yi Li · 发表于：Applied and Environmental Microbiology · 年份：2024 · DOI：10.1128/aem.02025-23 · 被引用次数：42 · 研究领域：Marine and coastal plant biology、Microbial Community Ecology and Physiology、Algal biology and biofuel production

ABSTRACT Marine bacteria play important roles in the degradation and cycling of algal polysaccharides. However, the dynamics of epiphytic bacterial communities and their roles in algal polysaccharide degradation during kelp decay are still unclear. Here, we performed metagenomic analyses to investigate the identities and predicted metabolic abilities of epiphytic bacterial communities during the early and late decay stages of the kelp Saccharina japonica . During kelp decay, the dominant epiphytic bacterial communities shifted from Gammaproteobacteria to Verrucomicrobia and Bacteroidetes. In the early decay stage of S. japonica , epiphytic bacteria primarily targeted kelp-derived labile alginate for degradation, among which the gammaproteobacterial Vibrionaceae (particularly Vibrio ) and Psychromonadaceae (particularly Psychromonas ), abundant in alginate lyases belonging to the polysaccharide lyase (PL) families PL6, PL7, and PL17, were key alginate degraders. More complex fucoidan was preferred to be degraded in the late decay stage of S. japonica by epiphytic bacteria, predominantly from Verrucomicrobia (particularly Lentimonas ), Pirellulaceae of Planctomycetes (particularly Rhodopirellula ), Pontiellaceae of Kiritimatiellota, and Flavobacteriaceae of Bacteroidetes, which depended on using glycoside hydrolases (GHs) from the GH29, GH95, and GH141 families and sulfatases from the S1_15, S1_16, S1_17, and S1_25 families to depolymerize fucoidan. The pathways for algal polys...