Overexpression of Iris. lactea var. chinensis metallothionein llMT2a enhances cadmium tolerance in Arabidopsis thaliana.
Metallothioneins (MTs) are cysteine-rich, low molecular weight, heavy metal-binding protein molecules. Here, a full-length cDNA homologue of MT2a (type 2 metallothionein) was isolated from the cadmium-tolerant species Iris. lactea var. chinensis (I. lactea var. chinensis). Expression of IlMT2a in I. lactea var. chinensis roots and leaves was up-regulated in response to cadmium stress. When the gene was constitutively expressed in Arabidopsis thaliana (A. thaliana), root length of transgenic lines was longer than that of wild-type under 50μM or 100μM cadmium stress. However, there was no difference of cadmium absorption between wild-type and trangenic lines. Histochemical staining by 3,3-diaminobenzidine (DAB) and nitroblue tetrazoliu (NBT) clearly demonstrated that transgenic lines accumulated remarkably less H2O2 and O2(-) than wild-type. Together, IlMT2a may be a promising gene for the cadmium tolerance improvement.
Institute of Botany, Jiangsu Province and Chinese Academy of Science, Nanjing 210014, China.
Chun-Sun
CS
Gu
College of Horticulture, Nanjing Agricultural University Nanjing 210014, China.
Liang-qin
LQ
Liu
Institute of Botany, Jiangsu Province and Chinese Academy of Science, Nanjing 210014, China.
Yan-Hai
YH
Zhao
Institute of Agrobiotechnology, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
Yan-ming
YM
Deng
College of Horticulture, Nanjing Agricultural University Nanjing 210014, China.
Xu-dong
XD
Zhu
Institute of Botany, Jiangsu Province and Chinese Academy of Science, Nanjing 210014, China. Electronic address: hsz1959@163.com.
Su-Zhen
SZ
Huang
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D002104:Cadmium / Q000032:analysis / Q000378:metabolism / Q000633:toxicity*; D015870:Gene Expression; D031323:Iris Plant / Q000145:classification / Q000235:genetics*; D008668:Metallothionein / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D018515:Plant Leaves / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism; D030821:Plants, Genetically Modified; D016415:Sequence Alignment; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics; D015854:Up-Regulation / Q000187:drug effects
D002104:Cadmium; D008668:Metallothionein
Arabidopsis; Cadmium stress; Iris. lactea var. chinensis; Metallothionein; Reactive oxygen species