3种锦鸡儿属植物过氧化物酶基因的克隆及表达分析

采用同源克隆技术分离了3种锦鸡儿属植物柠条锦鸡儿(Caragana korshinskii)、小叶锦鸡儿(C.microphylla)和中间锦鸡儿(C.intermedia)的过氧化物酶(POD)基因(分别命名为CkPOD、CmPOD和CiPOD),并对它们在干旱胁迫条件下的表达特征进行了分析。CkPOD、CiPOD、CmPOD基因的cDNA序列均包含有1 074bp的开放阅读框(ORF),编码的蛋白质由357个氨基酸构成,分子量为38.7kD。系统进化分析结果显示:3种锦鸡儿属植物的POD可以和鹰嘴豆等豆科植物的POD聚为一类,且CkPOD和CmPOD具有较近的亲缘关系,CiPOD与CkPOD和CmPOD的亲缘关系相对较远,这一结果与3种锦鸡儿属植物的进化地位一致,显示POD基因较为保守,可以为锦鸡儿属植物的系统分类提供参考。PEG模拟干旱胁迫能够强烈诱导CkPOD、CiPOD和CmPOD基因的表达,显示POD基因在锦鸡儿属植物抵御干旱胁迫过程中发挥着重要作用。研究结果可为解析锦鸡儿属植物的耐旱机理以及利用锦鸡儿属植物进行荒漠改良和生态修复提供理论和实验依据。

Isolation and Expression Feature of Peroxidase Genes from Three Caragana Species

Peroxidase (POD) genes were isolated from three Caragana species, C. korshinskii, C. microphylla and C. intermedia (designated as CkPOD, CmPOD and CiPOD, respectively) using homology based cloning techniques, and their expression profiles under drought stress conditions were investigated. All of the cDNAs of CkPOD, CiPOD and CmPOD contain an open reading frame (ORF) of 1 074 bp, encoding a protein of 357 amino acids with a theoretical molecular weight of 38.7 kD. Phylogenetic analysis showed that these three Caragana PODs could be clustered into one clade with their isoforms from leguminosae, including Cicer arietinum. The PODs of C. korshinskii and C. microphylla showed a closer relationship compared to C. intermedia POD, corresponding to evolutionary history of the three Caragana plants. Real time RT PCR revealed that the expression of the Caragana POD genes was strongly induced by PEG simulated drought stress, showing that the Caragana POD genes play an important role in resisting drought tolerance. These results may provide theoretical and experimental basis for understanding the drought tolerance mechanism of the Caragana plants and for their utilization in desert improvement and vegetation restoration programs.