拟南芥耐寒基因AtCOR15a在番茄中异源表达增强其耐寒性

Ectopic Expression of AtCOR15a Improves Cold Tolerance in Solanum lycopersicum

拟南芥耐寒基因AtCOR15a由冷诱导启动子RD29A控制后,重组进双元表达载体,经根癌农杆菌介导,将该基因导入‘Ailsa Craig’番茄。研究发现,筛选出的3个高表达转基因株系的耐寒性比野生型显著增强;外源基因AtCOR15a的表达量在低温处理过程中呈现先增后降的变化趋势,且在处理6h达到最大值;在冷胁迫下,该基因的表达促进了转基因植株中SlDehydrin-like(Sl DEHL)和SlDehydrin Ci7(SlCi7)等内源冷诱导基因的表达,降低了细胞膜透性和丙二醛(MDA)含量,减少了活性氧H_2O_2和O_2~.的积累,增强了超氧化物歧化酶、过氧化物酶和过氧化氢酶等活性氧清除酶的活性,提高了游离脯氨酸含量。因此,AtCOR15a异源表达能够显著增强转基因番茄的耐寒性。

Arabidopsis cold-tolerant gene AtCOR15a was controlled by cold-inducible promoter RD29A and was put into a binary expression vector. The gene was introduced into tomato variety Ailsa Craig mediated by Agrobacterium tumefaciens. The results showed that the cold tolerance of the three lines with high-level transgene expression was significantly enhanced compared with the wild type tomato. The expression levels of AtCOR15a in transgenic plants presented with a trend of first increasing and then decreasing,and reaching its maximum at 6 h after cold treatment at 4 ℃. Meanwhile,the expression of endogenous cold-inducible genes such as Sl Dehydrin-like（SlDEHL）and Sl Dehydrin Ci7（SlCi7）was promoted;the membrane permeability,malondialdehyde content,and the accumulations of reactive oxygen species H2O2 and O2-. were decreased;the activities of superoxide dismutase,peroxidase,and catalase,as well as free proline contents were increased in the transgenic lines compared with the wild type tomato under cold treatment. Therefore,ectopic expression of AtCOR15a could enhance the cold tolerance of transgenic tomato.