title: Molecular cloning of class III chitinase gene from Avicennia marina and its expression analysis in response to cadmium and lead stress.
abstract: Mangrove species have high tolerance to heavy metal pollution. Chitinases have been widely reported as defense proteins in response to heavy metal stress in terrestrial plants. In this study, a full-length cDNA sequence encoding an acidic and basic class III chitinase (AmCHI III) was cloned by using RT-PCR and RACE methods in Avicennia marina. AmCHI III mRNA expression in leaf of A. marina were investigated under Cd, Pb stresses on using real-time quantitative PCR. The deduced AmCHI III protein consists of 302 amino acids, including a signal putative peptide region, and a catalytic domain. Homology modeling of the catalytic domain revealed a typical molecular structure of class III plant chitinases. Results further demonstrated that the regulation of AmCHI III mRNA expression in leaves was strongly dependent on Cd, Pb stresses. AmCHI III mRNA expressions were significantly increased in response to Cd, Pb, and peaked at 7 days Cd-exposure, 7 days Pb-exposure, respectively. AmCHI III mRNA expression exhibited more sensitive to Pb stress than Cd stress. This work was the first time cloing chitinase from A. marina, and it brought evidence on chitinase gene involving in heavy metals (Cd(2+) and Pb(2+)) resistance or detoxification in plants. Further studies including the promoter and upstream regulation, gene over-expression and the response of mangrove chitinases to other stresses will shed more light on the role of chitinase in mangrove plants.
authors.affiliation: State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China.
authors.forename: Li-Ying
authors.initials: LY
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China. yswang@scsio.ac.cn.|Daya Bay Marine Biology Research Station, Chinese Academy of Sciences, Shenzhen, 518121, China. yswang@scsio.ac.cn.
authors.forename: You-Shao
authors.initials: YS
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China.
authors.forename: Jing-Ping
authors.initials: JP
authors.lastname: Zhang
authors.affiliation: Laboratory of Environmental Toxicology, Department of Ecology & Biodiversity, The University of Hong Kong, Pokfulam Road, Hong Kong, SAR, China.
authors.forename: Ji-Dong
authors.initials: JD
authors.lastname: Gu
mesh_terms: D000595:Amino Acid Sequence; D032407:Avicennia / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D001483:Base Sequence; D002104:Cadmium / Q000633:toxicity*; D002688:Chitinases / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D007854:Lead / Q000633:toxicity*; D008969:Molecular Sequence Data; D021141:Nucleic Acid Amplification Techniques; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D018076:DNA, Complementary; D010940:Plant Proteins; D012333:RNA, Messenger; D014874:Water Pollutants, Chemical; D002104:Cadmium; D007854:Lead; D002688:Chitinases; C110892:chitinase, class III
keywords: Aricennia marina; Cadmium; Chitinase; Clone; Gene expression; Lead; Mangrove plants