逆境胁迫下柽柳脂质转运蛋白基因 (ThLTP)的克隆与功能初步分析

从以刚毛柽柳为材料构建的NaCl胁迫的根cDNA文库中测序得到1条LTP基因序列,其全长为635 bp、编码116个氨基酸,命名为ThLTP基因。采用实时荧光定量RT-PCR的方法,分别对0.2 mol.L-1NaCl、150μmol.L-1CdCl2、20%(W/V)PEG6000、100μmol.L-1ABA及4℃下ThLTP基因在柽柳中的表达模式进行了分析,结果表明:ThLTP基因除了在4℃条件下根组织中为下调表达外,在其它处理中均表现为上调表达。将ThLTP基因克隆到大肠杆菌(Escherichia coli)的原核表达载体pET32a中,对重组菌Escherichia coli BL21(pET32a-LTP)的抗旱耐盐性进行分析。结果表明:在0.8%(W/V)NaCl和20%(W/V)PEG6000条件下,对照菌E.coli BL21(pET32a)无对数生长期,而重组菌E.colii BL21(pET32a-LTP)经过3 h的延迟生长后,进入到对数增长期,表明ThLTP可受盐、碱、低温诱导并能提高重组菌的抗旱耐盐能力。

Cloning and Function Analysis of Tamarix hispida Lipid Transfer Protein under Stress

In this study,a novel LTP gene which was named ThLTP was cloned from the cDNA library of Tamarix hispida root treated by 0.4 mol·L-1 NaCl.The sequence of ThLTP was 635 bp in full length,a protein with 116 amino acids residues.The authors examined the expression pattern of the ThLTP gene in leaf and root of T.hispida treated with 0.2 mol·L-1 NaCl,150 μmol·L-1 CdCl2,20%(W/V) PEG6000,100 μmol·L-1 ABA and 4 ℃ stresses for different time using real time RT-PCR.The results showed that the ThLTP gene was induced by all the treatments in leaf and root except the treatment of 4 ℃ treated in root.ThLTP was inserted into a prokaryotic expression vector(pET32a) to produce the recombinant expression vector pET32a-LTP.The Escherichia coli BL21(pET32a) could not live but the E.coli BL21(pET32a-LTP) came to the maximum after 3 h delayed growth under the stress of 0.8%(W/V) NaCl and 20%(W/V) PEG6000.The results showed that ThLTP may be a salt-and drought-tolerant gene and enhance the stress tolerance of the recombinant.