Poster: Heavy Metals

Abs # 102: Cloning, functional analysis and localization of a gene of phytochelatin synthases from Allium Sativum L.

Presenter:	Ma, Mi , mami@ns.ibcas.ac.cn
Authors	Ma, Mi  (A)   Jiang, Yingnan  (A)   Feng, Baomin  (A)   Li, Jiangchuan  (A)   Yang, Shude  (A)
Affiliations:	(A): Key Lab. of Photosynthesis & Mol. Environ. Phys., Inst. of Botany, Chinese Academy of Sciences

Phytochelatins play major roles in heavy metals tolerance for plants. A new cDNA named AsPCS encoding phytochelatin synthase has cloned from Allium Sativum L which can stand much high concentration of heavy metals by RACE. The full length AsPCS cDNA had 1868 bp and contained an open reading frame (GenBank accession No.AF384110) with 506 amino acids. The predicted polypeptide shared high homology with phytochelatin synthase of the other plants not only in N-terminator but also in C-terminator. Functional complementation studies confirmed the functional nature of this AsPCS gene in sequestering both cadmium and arsenite. Furthermore, RT-PCR analysis showed that the expression of AsPCS was increased both in roots and shoots of garlic after treated by cadmium, and the expression level in roots was higher than that in shoots. In roots the expression of AsPCS reached the top level after one hour exposed in 5 mmol/L Cd2+, suggesting that AsPCS can make a quick response to heavy metals stress. The localization of AsPCS expression is undergoing by in situ hybridization.