title: HbMT2, an ethephon-induced metallothionein gene from Hevea brasiliensis responds to H(2)O(2) stress.
abstract: Metallothioneins (MTs) are the cysteine-rich proteins with low molecular weight, which play important roles in maintaining intracellular ion homeostasis, detoxification of heavy metal ions and protecting against intracellular oxidative damages. In this study a novel ethephon-induced metallothionein gene, designated as HbMT2, was isolated and characterized from Hevea brasiliensis. The HbMT2 cDNA contained a 237 bp open reading frame encoding 78 amino acids and the deduced protein showed high similarity to the type 2 MTs from other plant species. Expression analysis revealed more significant accumulation of HbMT2 transcripts in leaves and latex than in roots and barks. The transcription of HbMT2 in latex was strongly induced by ethephon and hydrogen peroxide (H(2)O(2)) stress. Overproduction of recombinant HbMT2 protein gave the Escherichia coli cells more tolerance on Cu(2+) and Zn(2+), and the recombinant HbMT2 could scavenge the reactive oxidant species (ROS) in vitro. All these results indicated that HbMT2 could respond to ethephon stimulation and H(2)O(2) stress as a ROS scavenger in H. brasiliensis. It is also suggested that HbMT2 function in improving the tolerance of rubber trees to heavy metal ions, and repressing the ethephon-induced senilism and tapping panel dryness (TPD) development by ROS scavenge system in H. brasiliensis.
authors.affiliation: Key Laboratory of Tropical Crop Biotechnology, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, 4 Xueyuan Road, Haikou 571101, China.
authors.forename: Jiahong
authors.initials: J
authors.lastname: Zhu
authors.forename: Quanqi
authors.initials: Q
authors.lastname: Zhang
authors.forename: Rui
authors.initials: R
authors.lastname: Wu
authors.forename: Zhili
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003300:Copper / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D016166:Free Radical Scavengers / Q000494:pharmacology; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D028482:Hevea / Q000235:genetics* / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D017665:Hydroxyl Radical / Q000037:antagonists & inhibitors / Q000378:metabolism; D006900:Hydroxylation / Q000187:drug effects; D008668:Metallothionein / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009943:Organophosphorus Compounds / Q000494:pharmacology; D016877:Oxidants / Q000494:pharmacology; D010802:Phylogeny; D010937:Plant Growth Regulators / Q000494:pharmacology; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D011994:Recombinant Proteins / Q000378:metabolism / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012459:Salicylates / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013312:Stress, Physiological; D015032:Zinc / Q000494:pharmacology
chemical_list: D016166:Free Radical Scavengers; D009943:Organophosphorus Compounds; D016877:Oxidants; D010937:Plant Growth Regulators; D010940:Plant Proteins; D011994:Recombinant Proteins; D012459:Salicylates; D017665:Hydroxyl Radical; D003300:Copper; D008668:Metallothionein; D006861:Hydrogen Peroxide; D015032:Zinc; C005073:ethephon