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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Microbiol. | doi: 10.3389/fmicb.2019.01666

Compositional Shifts of Bacterial Communities Associated with Pyropia yezoensis and Surrounding Seawater Co-occurring with Red Rot Disease

 Yongwei Yan1,  Huichao Yang1, 2,  Lei Tang3, Jie Li1,  Yunxiang Mao3, 4 and Zhaolan Mo1, 2*
  • 1Yellow Sea Fisheries Research Institute (CAFS), China
  • 2Shanghai Ocean University, China
  • 3Ocean University of China, China
  • 4Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, China

Pyropia yezoensis is commercially the most important edible red alga in China, and red rot disease is viewed as one of the major constraints for its cultivation. Microbes within the oomycetic genus Pythium have been reported as the causative agents for this disease; however, little is known about the interactions between the disease and the epiphytic and planktonic bacterial communities. In the present study, bacterial communities associated with uninfected, locally infected, and seriously infected thalli collected from cultivation farms, and within seawater adjacent to the thalli, were investigated using in-depth 16S ribosomal RNA (rRNA) gene sequencing in conjunction with assessing multiple environmental factors. For both thalli and seawater, uninfected and infected communities were significantly different though alpha diversity was similar. Phylogenetic differences between epiphytic bacterial communities associated with P. yezoensis were mainly reflected by the relative changes in the dominant operational taxonomic units (OTUs) assigned as genus Flavirhabdus, genus Sulfitobacter, and family Rhodobacteraceae. The prevalent OTUs in seawater also differed in relative abundance across the communities and were affiliated with diverse taxa, including the phyla Actinobacteria, Verrucomicrobia, and Bacteroidetes, and the classes Alpha- and Gamma-proteobacteria. The differentiation of bacterial communities associated with P. yezoensis and seawater was primarily shaped by reactive silicate content and salinity, respectively. In particular, 14 potential indicators (two OTUs on P. yezoensis and twelve OTUs in seawater) were identified that significantly differentiated P. yezoensis health statuses and correlated with environmental changes. Overall, the present study provides insights into the alterations of bacterial communities associated with P. yezoensis and surrounding seawater co-occurring with red rot disease. Observed changes were closely associated with health status of algal host, and highlight the potential of using community differentiation to forecast disease occurrence.

Keywords: Red rot disease, Pyropia yezoensis, Seawater, Bacterial communities, Compositional shifts, Potential indicator

Received: 11 Dec 2018; Accepted: 04 Jul 2019.

Edited by:

Raquel Peixoto, Federal University of Rio de Janeiro, Brazil

Reviewed by:

Laetitia G. Wilkins, University of California, Davis, United States
Yan Cui, North Carolina State University, United States  

Copyright: © 2019 Yan, Yang, Tang, Li, Mao and Mo. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Prof. Zhaolan Mo, Yellow Sea Fisheries Research Institute (CAFS), Qingdao, China, mozl@ysfri.ac.cn