Cheng Lin, Zou Yijing, Ding Shuli, Zhang Jiajing, Yu Xiaolin, Cao Jiashu, Lu Gang
Key Laboratory of Horticultural Plant Growth, Development and Biotechnology, Ministry of Agriculture, Department of Horticulture, Zhejiang University, Hangzhou 310029, China.
J Integr Plant Biol. 2009 May;51(5):489-99. doi: 10.1111/j.1744-7909.2009.00816.x. Epub 2009 Mar 2.
Polyamines play an important role in plant response to abiotic stress. S-adenosyl-l-methionine decarboxylase (SAMDC) is one of the key regulatory enzymes in the biosynthesis of polyamines. In order to better understand the effect of regulation of polyamine biosynthesis on the tolerance of high-temperature stress in tomato, SAMDC cDNA isolated from Saccharomyces cerevisiae was introduced into tomato genome by means of Agrobacterium tumefaciens through leaf disc transformation. Transgene and expression was confirmed by Southern and Northern blot analyses, respectively. Transgenic plants expressing yeast SAMDC produced 1.7- to 2.4-fold higher levels of spermidine and spermine than wild-type plants under high temperature stress, and enhanced antioxidant enzyme activity and the protection of membrane lipid peroxidation was also observed. This subsequently improved the efficiency of CO(2) assimilation and protected the plants from high temperature stress, which indicated that the transgenic tomato presented an enhanced tolerance to high temperature stress (38 degrees C) compared with wild-type plants. Our results demonstrated clearly that increasing polyamine biosynthesis in plants may be a means of creating high temperature-tolerant germplasm.
多胺在植物对非生物胁迫的响应中发挥着重要作用。S-腺苷-L-甲硫氨酸脱羧酶（SAMDC）是多胺生物合成中的关键调节酶之一。为了更好地理解多胺生物合成调控对番茄高温胁迫耐受性的影响，通过农杆菌介导的叶盘转化法，将从酿酒酵母中分离得到的SAMDC cDNA导入番茄基因组。分别通过Southern杂交和Northern杂交分析对转基因和表达情况进行了确认。在高温胁迫下，表达酵母SAMDC的转基因植物产生的亚精胺和精胺水平比野生型植物高1.7至2.4倍，同时还观察到抗氧化酶活性增强以及对膜脂过氧化的保护作用。这随后提高了CO₂同化效率并保护植物免受高温胁迫，表明转基因番茄与野生型植物相比对高温胁迫（38℃）具有更强的耐受性。我们的结果清楚地表明，增加植物中的多胺生物合成可能是创造耐高温种质的一种手段。
