中文摘要：

环境因素如高盐、干旱或冷冻等严重制约着豆科重要牧草紫花苜蓿的生长发育和产量。根据已发表的盐生植物唐古特白刺蛋白激酶基因NtCIPK2的序列信息（序列号KC823044），利用PCR方法扩增其编码区cDNA，连接pMD-19T simple载体并测序，测序结果表明所克隆的DNA片段长度为1362bp，与GenBank上公布的序列完全一致。在此基础上构建植物超表达载体pPZP221-NtCIPK2，采用CaCl2冻融法将该表达载体转入农杆菌GV3101中，然后通过农杆菌介导的方法转化紫花苜蓿的下胚轴，形成愈伤组织后经庆大霉素筛选培养，最终获得7株抗性幼苗。对抗性幼苗进行庆大霉素基因的PCR检测，结果表明，NtCIPK2基因成功整合到紫花苜蓿基因组中，进一步对其进行外源基因的RT—PCR检测，发现只有3株幼苗中的外源基因实现了过量表达，这可能是由于基因插入位点的差异引发的基因沉默所致。本研究的开展为进一步分析转化植株在各种逆境胁迫条件的表现及其遗传稳定性，培育具有多重抗逆能力的苜蓿品种，促进苜蓿产业发展奠定基础。

英文摘要：

Adverse environmental factors such as salinity, drought and cold limit the growth and productivity of Medicago sativa, the most economically important forage legume worldwide. In this study, the complete coding sequence of NtCIPK2 was cloned from a halophyte Nitraria tangutorum, ligated into a pMD-19T simple vector and bi-directionally sequenced. The CDS of NtCIPK2 was 1362 bp and was identical with a NtCIPK2 gene in GenBank （accession number KC823044）. This fragment was inserted into the plant transformation vector pPZP221 under the control of the cauliflower mosaic virus （CaMV） 35S promoter, and then the recombinant vector pPZP221-NtCIPK2 was transferred to Agrobacterium tumefaciens strain GV3101 by the CaCl2 freeze-thaw method. Hypocotyls of M. sativa were transformed with GV3101 cells harboring pPZP221-NtCIPK2 by co-cultivation. Seven seedlings were obtained after callus induction and gentamycin selection. Then the seedlings were sampled to detect the gentamycin-resistant gene aacC1 by PCR and target gene NtCIPK2 by reverse transcription-PCR analysis. PCR detection indicated that NtCIPK2 was integrated into the Medicago genome in all seedlings. However, RT--PCR detection suggested that NtCIPK2 was overly expressed at the transcriptional level in three seedlings, and gene silencing might be occurring in some seedlings due to the difference in insertion sites of the exogenous gene. A solid foundation for further study of the performance and genetic stability of transformed plants and advanced breeding of Medicago varieties with strong resistance to abiotic stresses is offered.