Genome-wide identification of chitinase genes in Thalassiosira pseudonana and analysis of their expression under abiotic stresses.

Affiliation

Cheng H(1)(2)(3), Shao Z(4)(5), Lu C(1)(2)(3), Duan D(6)(7)(8).
Author information:
(1)Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, P. R. China.
(2)Laboratory for Marine Biology and Biotechnology, Pilot Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, P. R. China.
(3)University of Chinese Academy of Sciences, Beijing, 100049, P. R. China.
(4)Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, P. R. China. [Email]
(5)Laboratory for Marine Biology and Biotechnology, Pilot Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, P. R. China. [Email]
(6)Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, P. R. China. [Email]
(7)Laboratory for Marine Biology and Biotechnology, Pilot Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, P. R. China. [Email]
(8)State Key Laboratory of Bioactive Seaweed Substances, Qingdao Bright Moon Seaweed Group Co Ltd, Qingdao, 266400, P. R. China. [Email]

Abstract

BACKGROUND: The nitrogen-containing polysaccharide chitin is the second most abundant biopolymer on earth and is found in the cell walls of diatoms, where it serves as a scaffold for biosilica deposition. Diatom chitin is an important source of carbon and nitrogen in the marine environment, but surprisingly little is known about basic chitinase metabolism in diatoms. RESULTS: Here, we identify and fully characterize 24 chitinase genes from the model centric diatom Thalassiosira pseudonana. We demonstrate that their expression is broadly upregulated under abiotic stresses, despite the fact that chitinase activity itself remains unchanged, and we discuss several explanations for this result. We also examine the potential transcriptional complexity of the intron-rich T. pseudonana chitinase genes and provide evidence for two separate tandem duplication events during their evolution. CONCLUSIONS: Given the many applications of chitin and chitin derivatives in suture production, wound healing, drug delivery, and other processes, new insight into diatom chitin metabolism has both theoretical and practical value.