Pyramiding Mn-superoxide dismutase transgenes to improve persistence and biomass production in alfalfa.
Pyramiding Mn-superoxide dismutase transgenes to improve persistence and biomass production in alfalfa.
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DOI：
10.1093/jexbot/53.372.1343
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发表时间：
2002-05
影响因子：
6.9
通讯作者：
Karen E. Samis;S. Bowley;B. Mckersie
中科院分区：
文献类型：
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作者：
Karen E. Samis;S. Bowley;B. Mckersie
表达单独的超氧化物歧化酶(SOD)转基因可以提高紫花苜蓿的环境胁迫耐受性和生物量。本研究的目的是验证转基因SOD胁迫耐受机制之间存在协同作用的假设，特别是同时表达两个转基因比单独表达一个转基因带来更大的好处。通过对一个半合子MIT-MnSOD植株和一个半合子Chl-MnSOD转基因紫花苜蓿植株的有性杂交产生的F(1)家系的评估，验证了这一假说，该转基因紫花苜蓿植株之前曾在田间试验中进行过筛选，以提高持久性。Southern分析表明，这两个亲本都有MnSOD基因的单插入区域，遗传符合预期的孟德尔比率。天然PAGE凝胶和酶抑制实验表明转基因MnSOD同工酶具有活性。转基因植株F(1)的贮藏器官(树冠+根)生物量显著高于未转基因的后代。转基因的联合表达导致了总超氧化物歧化酶活性的数值增加。然而，与只有一个或另一个转基因的同胞相比，含有两个转基因的F(1)后代的地上部和贮藏器官生物量较低，这一结果不支持作者的假设。有人推测，如果要在同一植物中聚合密切相关的转基因，可能需要一个低于35S表达的启动子。
Expression of individual superoxide dismutase (SOD) transgenes improves environmental stress tolerance and biomass production in alfalfa (Medicago sativa L.). The objective of this study was to test the hypothesis that synergy exists between transgenic SOD stress-tolerance mechanisms, specifically that the simultaneous expression of two SOD transgenes confers greater benefit than the expression of a single SOD transgene. The hypothesis was tested through an evaluation of an F(1) family generated through a sexual cross of a hemizygous Mit-MnSOD plant and a hemizygous Chl-MnSOD-transgenic alfalfa plant which had previously been screened in field trials for improved persistence. Southern analyses revealed that the parents each had single insertion regions of the MnSOD cDNA and the inheritance followed the expected Mendelian ratios. Native PAGE gels and enzyme inhibition assays revealed the activity of the transgenic MnSOD isozymes. F(1) progeny containing either the Mit-MnSOD or the Chl-MnSOD transgene had significantly higher storage organ (crown+root) biomass compared to non-transgenic siblings. The joint expression of the transgenes resulted in a numerical increase in total SOD activity. However, F(1) progeny containing both transgenes had lower shoot and storage organ biomass compared to siblings having only one or the other transgene, a result that did not support the authors' hypothesis. It was postulated that a promoter with lower expression than 35S may be necessary if closely related transgenes are to be pyramided in the same plant.