摘要
分别用光诱导型启动子（PrbcS）和组成型启动子（Ca MV35S）驱动柠檬酸合酶基因（cs）在转基因烟草中过量表达,比较转基因烟草中柠檬酸的含量和分泌量及其铝耐受性的变化.结果表明：诱导型转基因株系的CS酶活性是野生型的2.3~2.4倍,组成型转基因株系的酶活性是野生型的1.6~2倍;在30μmol·L-1铝胁迫下,诱导型转基因植株的根相对伸长量是野生型的2.8~2.9倍,组成型的根相对伸长量是野生型的2~2.3倍;在无铝或300μmol·L-1铝胁迫下,转基因烟草叶片和根中柠檬酸含量均高于野生型,其中诱导型转基因植株叶片中柠檬酸含量高于组成型转基因植株,转基因烟草柠檬酸的分泌量分别是野生型的1.8~2.0倍和3.0~3.3倍;在有铝胁迫的珍珠岩基质上培养时,转基因烟草的生长情况好于野生型.这些结果证明,与Ca MV35S相比,采用PrbcS启动子控制cs基因的过量表达可更有效地增加转基因烟草中CS的酶活性及叶片中柠檬酸的合成量,同时也能更有效地提高转基因烟草柠檬酸的分泌量,从而增强其对铝毒害的抵御能力.
Overexpression of citrate synthase（cs） cDNA of tobacco was driven by the light-inducible promoter of rubisco small subunit（PrbcS） and the constitutive promoter CaMV 35S（35S） in transgenic tobacco plants,respectively.The changes in citrate contents and exudations as well as Al tolerances in transgenic PrbcS and 35S tobacco plants were compared.The results showed that CS enzyme activities were increased 2.3-2.4 folds and 1.6-2 folds in transgenic PrbcS and 35S tobacco plants as compared with wild tobacco（WT） plants,respectively.When exposed to 30 μmol·L-1 Al,relative root elongation rates of transgenic PrbcS and 35S tobacco plants were also increased 2.8-2.9 folds and 2-2.3 folds as compared with WT,respectively.Citrate contents in the transgenic tobacco leaves were significantly increased compared with the WT plants,which were especially pronounced in transgenic PrbcS tobacco plants.Citrate contents in the transgenic PrbcS tobacco roots and citrate exudation from their roots were elevated more effectively compared with transgenic 35S plants under acidic conditions with 300 μmol·L-1 Al3＋ stress.When grown in a perlite medium supplied with 500 μmol·L-1 Al3＋ nutritional solution twice a week,all transgenic tobacco lines showed better growth performance than the WT plants.The results above suggest that CS enzyme activity and citrate synthesis are increased more effectively in transgenic tobacco when cs overexpression is driven by PrbcS promoter.Consequently,citrate exudations and Al tolerance in transgenic PrbcS tobacco plants are also enhanced and improved more evidently compared with transgenic 35S ones.
出处
《浙江大学学报（农业与生命科学版）》
CAS
CSCD
北大核心
2011年第1期31-39,共9页
Journal of Zhejiang University:Agriculture and Life Sciences
基金
国家重点基础研究发展计划"973"资助项目(2007CB108901)
关键词
柠檬酸合酶
铝耐受性
转基因烟草
光诱导启动子
组成型启动子
citrate synthase
Al tolerance
transgenic tobacco
light-inducible promoter
constitutive promoter
