大豆ASR表达提高酵母和烟草细胞对Cu^(2+)耐受力

Expression of ASR gene confers copper tolerance to yeast mutant and transgenic tobacco BY-2 cells

利用实时荧光定量聚合酶链式反应(polymerase chain reaction,PCR)技术,证明大豆幼苗在150μmol/L Cu SO4胁迫3 h后,其叶和根内Gm ASR基因表达均上调.将大豆Gm ASR基因转化Cu2+敏感型酵母菌ΔCUP 2和烟草悬浮细胞BY-2,Gm ASR蛋白的表达可增强重组酵母和转基因烟草细胞抗Cu2+胁迫的能力.利用大肠杆菌表达体系表达、分离并纯化大豆Gm ASR蛋白,体外实验证明,Gm ASR蛋白可与Cu2+结合,并具有清除羟基自由基的能力.研究结果推测,ASR蛋白可通过螯合Cu2+降低细胞内Cu2+浓度,提高植物对Cu2+胁迫的耐受力.

Expression analysis by quantitative real-time polymerase chain reaction （ PCR ） shows that GmASR is identified with increased expression in the roots and leaves of soybean seedlings under 150 μmol/L CuSO4 stress for 3 h. The GmASR gene is introduced into Cu2＋ sensitive yeast ΔCUP2 and tobacco suspension BY-2 cells, and we find that expression of GmASR protein could improve copper tolerance of the recombinant yeast mutant and transgenic tobacco BY-2 cells. GmASR protein is induced, separated and purified by using the recombinant E. Coli. It is confirmed that the GmASR protein can bind Cu2＋ and also inhibit hydroxyl radical generation in vitro. We can spec-ulate that the GmASR protein would enhance the plant tolerance of copper stress by chelating Cu2＋, reducing intra-cellular Cu2＋ concentration and oxidant damage.