摘要：

非生物胁迫如干旱、土壤盐碱化等严重影响着农作物的生长发育,农作物产量明显受限。大豆GmRPK2基因与拟南芥抗逆基因AtRPK1高度同源,为探究其抗逆功能和作用机理,构建了GmRPK2基因过表达载体并转化拟南芥筛选获得纯合体。抗逆性检测结果表明,在高盐、PEG和ABA处理下,GmRPK2过表达拟南芥种子的萌发率显著低于野生型,其幼苗阶段根的生长量也明显小于野生型。成株阶段抗逆性检测表明,盐、旱胁迫下过表达拟南芥的生长受抑现象更为明显。为探究其抗逆性降低的内在机理,对GmRPK2过表达拟南芥进行了生理指标检测。结果表明,高盐胁迫后其叶绿素含量明显低于野生型,其丙二醛和电导率则明显较高,DAB染色比野生型更深;旱胁迫后过表达拟南芥的脯氨酸和可溶性糖含量明显较低,失水率明显较高。荧光定量PCR检测发现,GmRPK2基因在拟南芥中过表达后明显抑制了SAD1、P5CS1和ADH1的表达。因此,GmRPK2基因可能通过抑制CDPK抗逆信号转导通路、降低脯氨酸积累和减弱ABA信号传导通路影响拟南芥的抗逆性。

关键词: 大豆, GmRPK2, 类受体激酶, 抗逆功能, 生理指标, 信号转导通路

Abstract:

Abiotic stresses such as drought and soil salinization seriously affect the growth,development and yield of crops.GmRPK2 gene was cloned and constructed into the overexpression vector,then the vector was transformed into Arabidopsis thaliana and the homozygotes was screened.Under PEG,NaCl and ABA stress,the resistance of GmRPK2 overexpression Arabidopsis was tested.The results showed that the germination rate of the overexpressed Arabidopsis seeds was significantly lower than wild type.The elongation of the overexpressed Arabidopsis seedlings roots was also shorter than that of wild-type.In the stress resistance test of Arabidopsis plants,it was found that after salt stress and drought stress treatment,the inhibition of transgenic Arabidopsis plants was more obvious than that of wild-type Arabidopsis plants.The stress resistance test at adult stage showed that the growth inhibition of overexpressed Arabidopsis was more obvious under salt and drought stress.In order to explore the internal mechanism of the reduction of its stress resistance,the physiological indexes of GmRPK2 overexpressed Arabidopsis were detected.The results showed that,the chlorophyll content of overexpressed Arabidopsis was significantly lower,the malondialdehyde and conductivity were obviously higher,and the DAB staining was deeper than that of the wild type.After drought stress treatment,the contents of proline and soluble sugar of overexpressed Arabidopsis were obviously lower than those of wild type,and the water loss rate was obviously higher.The results of RT-PCR showed that GmRPK2 overexpressed in Arabidopsis obviously inhibited SAD1,P5CS1 and ADH1 expression.It was preliminarily speculated that it might inhibit the transmission of stress signals by inhibiting the expression of these genes.Therefore,GmRPK2 gene may affect the stress resistance of Arabidopsis by inhibiting CDPK stress resistance signal transduction pathway,reducing proline accumulation and weakening ABA signal transduction pathway.

Key words: Soybean, GmRPK2, Receptor like kinases, Stress resistance function, Physiological index, Signal transduction pathway