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2025年4月4日 星期五
  2017, Vol. 25 Issue (5): 729-738    
  研究论文与报告 本期目录 | 过刊浏览 | 高级检索 |
烟草中过表达丹参SAMDC基因增强其抗旱性
刘玉,孙耿,仲昭辉,郑雪莲,邓科君
电子科技大学
Overexpression of SAMDC Gene from Salvia miltiorrhiza Enhances Drought Tolerance in Transgenic Tobacco (Nicotiana tabacum)
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摘要 摘 要 S-腺苷甲硫氨酸脱羧酶(SAMDC)是多胺合成代谢中的关键酶。本研究利用RT-PCR从丹参(Salvia miltiorrhiza)中获得了全长的SAMDC序列(GenBank No. GU983041.1),即SmSAMDC,与其他植物物种中的SAMDC氨基酸序列具有较高的同源性。为研究多胺在植物抗旱中的作用,利用根癌农杆菌(Agrobacterium tumefaciens)介导的叶盘转化法将SmSAMDC导入到烟草(Nicotiana tabacum)中,得到稳定表达SmSAMDC的转基因的T0和T1代烟草,用以抗干旱分析。SmSAMDC在烟草中的异源表达明显地提高了转基因T0和T1代烟草的抗旱能力。生理研究发现,在干旱条件下,转SmSAMDC烟草具有更高的相对含水量(relative water content, RWC)和抗氧化酶活性;相对较低的丙二醛(malondialdehyde, MDA)和超氧阴离子自由基(O2·-)含量。并且,在干旱胁迫环境中,SmSAMDC在烟草的过表达显著地促进了转基因烟草中过氧化氢(H2O2)的积累。本研究证明过表达SmSAMDC能提高转基因烟草的抗旱能力,为SmSAMDC在其他物种的应用提供了理论依据。
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刘玉
孙耿
仲昭辉
郑雪莲
邓科君
关键词 过表达S-腺苷甲硫氨酸脱羧酶(SAMDC)丹参干旱胁迫烟草    
Abstract:Abstract S-adenosylmethionine decarboxylase (SAMDC) is a crucial enzyme related to biosynthesis of polyamines (PAs). In this study, the full-length 1 083 bp cDNA sequence of Sesamum indicum (SmSAMDC) (GenBank No. GU983041.1) was amplified from total mRNA of S. miltiorrhiza by RT-PCR and designated as SmSAMDC. Phylogenetic analysis of this deduced protein inferred using the unweighted pair-group method with arithmetic means (UPGMA) method indicated that SmSAMDC was quite similar to SAMDC from other plants, especially S. indicum up to 82%. The SmSAMDC protein showed an obvious homology with other species of plants. To reveal the role of polyamines against drought, the ampli?ed coding sequence of SmSAMDC was overexpressed in tobacco (Nicotiana tabacum). To screen the positive plants, PCR analysis was performed and DNA of the transgenic lines (T0 and T1 plants) was used as templates. RT-PCR analysis was performed using gene-specific primers to screen 5 transgenic plants, and an amplicon of 500 bp was showed. These results clearly demonstrated the overexpression of the SmSAMDC gene in the genome of the transgenic plants. During drought, the growth rates of the wild type and transgenic tobacco significantly decreased, and their development process was also inhibited. However, after 18 d drought treatment, obvious wilting was observed in wild type, meanwhile, much fewer wilting was detected in T1 generation plants of transgenic tobacco from lines S-7, S-8 and S-14 until 18. After rewatering, much more transgenic tobacco plants survived and recovered comparing with the wild type. This results showed that overexpression of SmSAMDC greatly increased the survival rate under drought condition. The physiological study indicated plant lines with SmSAMDC showed a higher relative water content (RWC) and stronger activities of antioxidant enzymes, with lesser contents of malondialdehyde (MDA) and superoxide radical anions (O2·-) compared with the wild type lines under drought condition. To reveal the role of SmSAMDC in preventing membrane injury caused by drought stress, the activities of several antioxidant enzymes, comprising of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) were analyzed. And the activities of these enzymes were almost the same between the transgenic lines and wild type in normal growth. However, after 18 d of drought treatment, the activities of SOD and CAT were slightly higher in the transgenic lines than that in wild type, on the other hand, the activities of POD dropped a lot. To further explore the role of SmSAMDC in ROS reduction, the accumulation of O2·- and H2O2 were examined in transgenic lines under drought stress using nitroblue tetrazolium (NBT) and diaminobenzidine (DAB) staining, separately. The staining results indicated that overexpression of SmSAMDC decreased the accumulation of O2·- (NBT staining) and increased H2O2 (DAB staining) under drought stress for 18 d comparing to wild type. Furthermore, the results showed that overexpression of SmSAMDC signi?cantly increased the accumulation of hydrogen peroxide (H2O2) in tobacco under drought stress. These results indicated that overexpression of SmSAMDC increased drought tolerance in tobacco. Furthermore, this is the foundation that SmSAMDC could be applied in other species.
Key wordsOverexpression    S-adenosylmethionine decarboxylase (SAMDC)    Salvia miltiorrhiza    Drought tolerance    Tobacco
收稿日期: 2016-12-14      出版日期: 2017-05-02
基金资助:中央大学基础研究基金;国家自然科学基金
通讯作者: 郑雪莲     E-mail: zhengxl@uestc.edu.cn
引用本文:   
刘玉 孙耿 仲昭辉 郑雪莲 邓科君. 烟草中过表达丹参SAMDC基因增强其抗旱性[J]. , 2017, 25(5): 729-738.
链接本文:  
http://journal05.magtech.org.cn/Jwk_ny/CN/     或     http://journal05.magtech.org.cn/Jwk_ny/CN/Y2017/V25/I5/729
 
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