过表达单脱氢抗坏血酸还原酶基因提高番茄抗UV-B胁迫能力

以野生型（WT）和转正义叶绿体单脱氢抗坏血酸还原酶基因（LeMDAR）番茄为试材，探讨了UV-B胁迫下过表达LeMDAR对番茄抗氧化能力的影响。测定了不同时间uV-B处理下番茄抗坏血酸（AsA）含量，脱氢抗坏血酸（DHA）含量，单脱氢抗坏血酸还原酶（MDAR）活性，光合速率和叶绿素荧光参数等。在UV-B处理下，转基因番茄植株的AsA含量、MDAR酶及抗坏血酸过氧化物酶（APx）活性、H：0：和超氧阴离子清除速率、净光合速率（只）高于野生型番茄。此外，紫外胁迫下，转基因株系丙二醛（MDA）含量和相对电导率（REC）较野生型增加的少。上述结果表明，MDAR对抗抗坏血酸再生具有重要作用，过表达LeMDAR提高了番茄植株抗氧化能力，对光合机构有保护作用。

Overexpression of Chloroplastic Monodehydroascorbate Reductase Gene Enhanced Tolerance to UV-B Stress in Tomato

The wild type （WT） and transgenic tomato lines with overexpression of ehloroplastic monodehydroascorbate reductase gene （LeMDAR） were used to investigate the antioxidant ability under UV-B stress. Contents of ascorbic acid （AsA） and dehydrogenation ascorbic acid （DHA）, monodehydroascorbic acid reductase （MDAR） activities, net photosynthetic rate （Pn） and chlorophyll fluorescence parameters were measured under UV-B treatment. Compared with WT, AsA content, activities of APX and MDAR in transgenic plants increased and the contents of H20： and 02 decreased. In transgenic plants, the higher Pn, the lower MDA content and the relative electric conductivity （REC） were detected, compared with WT under UV-B. These results indicated that MDAR has an important role in AsA regeneration, and overexpression of LeMDAR improved the plant antioxidant ability and protected photosynthetic mechanism.