Functional Characterization and Evolutionary Analysis of Glycine-Betaine Biosynthesis Pathway in Red Seaweed Pyropia yezoensis

• Published in: Marine drugs 2019-01, Vol.17 (1), p.70
• Main Authors: Mao, Yunxiang, Chen, Nianci, Cao, Min, Chen, Rui, Guan, Xiaowei, Wang, Dongmei
• Format: Article
• Language: English
• Subjects: Abiotic factors; Acclimation; Acclimatization; Aldehyde dehydrogenase; Aldehydes; Algae; Amino acids; Bacteria; BADH; betaine; Biosynthesis; CDH; Choline; Choline dehydrogenase; Copy number; Dehydration; Dehydrogenase; Dehydrogenases; desiccation; Drought; Enzymes; Gene duplication; Gene regulation; Genes; Genomes; Glycine; Glycine (amino acid); Glycine betaine; Hydration; Intertidal environment; Intertidal zone; Metabolic flux; Metabolism; Methyltransferase; Molecular modelling; N-Methyltransferase; Osmotic stress; PEAMT; Phosphoethanolamine N-methyltransferase; Phylogenetics; Phylogeny; Protein structure; Proteins; Pyropia; Pyropia yezoensis; Quaternary; Quaternary structure; Rhodophyta; Seaweeds; Stabilizing; Stresses; Transcription
• ISSN: 1660-3397; 1660-3397
• DOI: 10.3390/md17010070

The red seaweed is an ideal research model for dissecting the molecular mechanisms underlying its robust acclimation to abiotic stresses in intertidal zones. Glycine betaine (GB) was an important osmolyte in maintaining osmotic balance and stabilizing the quaternary structure of complex proteins under abiotic stresses (drought, salinity, etc.) in plants, animals, and bacteria. However, the existence and possible functions of GB in remain elusive. In this study, we observed the rapid accumulation of GB in desiccated blades, identifying its essential roles in protecting cells against severe osmotic stress. Based on the available genomic and transcriptomic information of , we computationally identified genes encoding the three key enzymes in the GB biosynthesis pathway: phosphoethanolamine -methyltransferase (PEAMT), choline dehydrogenase (CDH), and betaine aldehyde dehydrogenase (BADH). had an extraordinarily expanded gene copy number of CDH (up to seven) compared to other red algae. Phylogeny analysis revealed that in addition to the one conservative CDH in red algae, the other six might have originated from early gene duplication events. In dehydration stress, multiple CDH paralogs and PEAMT genes were coordinating up-regulated and shunted metabolic flux into GB biosynthesis. An elaborate molecular mechanism might be involved in the transcriptional regulation of these genes.