异源过表达NtCIPK5提高转基因拟南芥对盐和干旱胁迫的耐受性

Heterologous overexpression of NtCIPK5 improves the tolerance to saltand drought stresses in Arabidopsis thaliana

钙调磷酸酶B类蛋白互作蛋白激酶CIPK(CBL-interacting protein kinase)是植物体内一类响应钙离子信号变化的丝氨酸/苏氨酸蛋白激酶,在植物的生长发育调控和非生物胁迫响应等方面发挥重要的作用。然而,目前关于CIPK的研究主要集中在模式植物和作物中,荒漠植物中相关研究仍较为匮乏。本研究从对干旱、盐碱环境具有极强适应性的蒺藜科荒漠沙生植物唐古特白刺(Nitraria tangutorum)中克隆了NtCIPK5基因并成功转入拟南芥中,分析其在植物响应盐和干旱胁迫过程中发挥的作用。实时荧光定量PCR(qRT-PCR)分析发现,NtCIPK5在唐古特白刺幼苗茎中表达量最高,同时其表达受聚乙二醇(PEG)、NaCl、脱落酸(ABA)和CaCl_(2)诱导。在盐和干旱胁迫下,转基因拟南芥的生长状况明显优于野生型,表现为具有更高的存活率、根长、侧根数、鲜重和叶绿素含量,叶中丙二醛(MDA)和过氧化氢(H_(2)O_(2))含量更低,表明NtCIPK5的过表达缓解了盐和干旱胁迫对拟南芥造成的生长抑制和氧化损伤;进一步研究发现,NtCIPK5的过表达显著增加了盐和干旱胁迫下转基因拟南芥超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)的活性以及脯氨酸的含量,抗逆相关基因的转录水平也被显著提升,表明NtCIPK5能通过提高抗逆基因表达和抗氧化酶活性提升转基因植物对盐和干旱胁迫的耐受性。

Calcineurin B-like protein(CBL)-interacting protein kinase is a serine/threonine protein kinase in response to calcium signal changes,which plays an important role in plant growth and development regu-lation and abiotic stress response.However,the research on CiPk is mainly focused on model plants and crops,and the relevant research in desert plants is still scarce.In this study,NtCiPK5 gene in a desert halo-phyte(Nitraria tangutorum)was cloned and successfully transferred into Arabidopsis thaliana,and its role in plant response to salt and drought stress was analyzed.Real-time PCR(qRT-PCR)analysis indicated that NtCiPK5 showed the highest expression level in the stems,and its transcription was induced by poly(ethylene glycol)(PEG),NaCl,abscisic acid(ABA)and CaCl_(2).Under salt and drought stress,the growth status of transgenic A.thaliana was significantly better than that of wild-type plant.The survival rate,root length,number of lateral roots,fresh weight and chlorophyll content of transgenic lines were higher than wild-type.At the same time,the transgenic lines had lower content of malondialdehyde(MDA)and hydrogen peroxide(H_(2)O_(2))and suffered less oxidative damage.NtCIPK5 significantly increased the activities of superoxide dismutase(SOD),peroxidase(POD),catalase(CAT)and proline content of transgenic lines under salt and drought stress.At the same time,overexpression of NtCiPK5 increased the transcription level of stress related genes in plant.Above results showed that NtCIPK5 can alleviate the growth inhibition and oxidative damage of plants caused by salt and drought stress by improving the expression of plant stress related genes and the activity of antioxidant enzymes,so as to improve the tolerance of plants to abiotic stress.