[Objective] The expression of DNA damage repair gene under salt stress is helpful to reveal the relationship between DNA damage repair and salt tolerance of halophyte.[Method]According to the transcriptome of Halostachys caspica under salt stress,a DNA damage repair gene DNA polymerase lambda(HcDNA pol λ)was cloned from Halostachys caspica by RACE.[Result]Sequence analysis indicated that HcDNA pol λ contained an open reading frame of 1,335 bp,which encodes 444 amino acids.Conserved domain analysis showed that HcDNA pol λ was the number of DNA polymerase X family,and phylogenetic tree analysis indicated that HcDNA pol λ was an independent branch,which was an stable hydrophilic proteins sub-celled nuclear.Real time fluorescent quantitative PCR analysis showed that the expression of HcDNA pol λ of assimilating branches gradually up-regulated with the increase of NaCl concentration.At 300 mmol/L NaCl treatments,the expression levels of HcDNA pol λ were increased 3 fold and 5 fold for 7 days and for 14 days,respectively.Finally,at 700 mmol/L NaCl treatment for 14 days,the expression levels of HcDNA pol λ increased 20 fold and reached the peak.[Conclusion]The expression of HcDNA pol λ gene could be induced by salt stress.%[目的]开展盐胁迫下DNA损伤修复基因的表达研究,有助于揭示DNA损伤修复与盐生植物耐盐的相关性.[方法]根据盐胁迫下盐穗木转录组测序结果,利用RACE技术克隆获得了盐穗木DNA损伤修复基因HcDNA聚合酶λ(HcDNA pol λ)基因,开放阅读框1 335 bp,编码444个氨基酸.[结果]保守结构域分析显示,HcDNA pol λ基因属于DNA聚合酶X家族成员,系统进化分析显示HcDNA pol λ 为独立的分支,亚细胞定位于细胞核,无信号肽且不含跨膜区域的亲水蛋白.实时荧光定量PCR分析表明,随着NaCl胁迫浓度的增加,同化枝的HcDNA pol λ基因的表达逐渐上调,在300 mmol/L NaCl处理 7和14 d时,HcDNA pol λ 的表达分别增加3和5倍.最后在700 mmol/L NaCl处理14 d时,HcDNA pol λ的表达增加20倍,达到峰值.[结论]HcDNA pol λ基因的表达受盐胁迫的诱导.
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