Iron-superoxide dismutase expression in transgenic alfalfa increases winter survival without a detectable increase in photosynthetic oxidative stress tolerance
Iron-superoxide dismutase expression in transgenic alfalfa increases winter survival without a detectable increase in photosynthetic oxidative stress tolerance
复制标题
DOI：
10.1104/pp.122.4.1427
复制
发表时间：
2000-04-01
期刊：
影响因子：
7.4
通讯作者：
Bowley, SR
中科院分区：
文献类型：
--
作者：
McKersie, BD;Murnaghan, J;Bowley, SR
为了研究铁超氧化物歧化酶（Fe-SOD）过表达是否能提高转基因苜蓿（Medicagosativa L.）植物中，用载体pEXSOD 10转化两种基因型，所述载体pEXSOD 10含有拟南芥Fe-SOD的cDNA，所述拟南芥Fe-SOD具有叶绿体转运肽和花椰菜花叶病毒35 S启动子。一种新的Fe-SOD检测到本地PACE在温室和田间生长的转基因植物，但独立的转基因植物之间的活性不同。Fe-SOD活性的增加与增加冬季生存超过2年的田间试验，但不与氧化胁迫耐受性所测量的抗甲基紫精，超氧化物发生器的叶片。总地上部干物质生产超过2个收获年与Fe-SOD活性。有没有检测到的差异，主要冻害的模式，所示的活体染色，也没有额外的碳水化合物的积累在田间驯化的转基因苜蓿植物的根。我们没有检测到任何差异，在一个高Fe-SOD活性的转基因植物的生长与非转基因对照相比。因此，冬季生存的改善似乎不是与光合作用相关的氧化应激耐受性改善的结果，也不是主要冻害变化的结果。我们认为，Fe-SOD过表达减少继发性损伤症状，从而增强了冬季经历的压力恢复。
To determine whether overexpression of Fe-superoxide (SOD) dismutase would increase superoxide-scavenging capacity and thereby improve the winter survival of transgenic alfalfa (Medicago sativa L.) plants, two genotypes were transformed with the vector pEXSOD10, which contains a cDNA for Arabidopsis Fe-SOD with a chloroplast transit peptide and cauliflower mosaic virus 35S promoter. A novel Fe-SOD was detected by native PACE in both greenhouse- and field-grown transgenic plants, but activity varied among independent transgenic plants. The increased Fe-SOD activity was associated with increased winter survival over 2 years in field trials, but not with oxidative stress tolerance as measured by resistance of leaves to methyl viologen, a superoxide generator. Total shoot dry matter production over 2 harvest years was not associated with Fe-SOD activity. There was no detectable difference in the pattern of primary freezing injury, as shown by vital staining, nor was there additional accumulation of carbohydrates in field-acclimated roots of the transgenic alfalfa plants. We did not detect any difference in growth of one transgenic plant with high Fe-SOD activity compared with a non-transgenic control. Therefore, the improvement in winter survival did not appear to be a consequence of improved oxidative stress tolerance associated with photosynthesis, nor was it a consequence of a change in primary freezing injury. We suggest that Fe-SOD overexpression reduced secondary injury symptoms and thereby enhanced recovery from stresses experienced during winter.