棉花GDP-甘露糖-3′,5′-异构酶基因的克隆及其表达分析

摘要

On the basis of salt stress-related EST sequences of Gossypium hirsuturm L. ,a GDP-mannose-3' ,5'-epimerase( GME)gene was isolated by the 3',5'-RACE technology,named GhGME. The full-length cDNA of GhGME is 1467 bp, containing an 1131 bp ORF which encodes 376 amino acids. The relative molecular weight of GhG-ME protein is 42. 396 kDa,and its isoelectric point (pI) is 6. 291. Fluorescent quantitative real-time RT-PCR analysis of the expression of GhGME in roots, stems, leaves and three different treatments were employed. The results showed that the relative expression of GhGME was higher in roots and stems than that in leaves. And the expression of GhGME was up-regulated under either the 4℃ or 200 mmol/L NaCl treatment, but that was down-regulated, under the 100 μmol/L GA3 treatment. Differential expressions of GhGME under various treatments suggest that GhGME may play an important role in cotton acclimatization to environmental stresses. The response of GhGME to various stresses in this study indicates that GhGME should be further evaluated in fuction.%根据棉花盐胁迫相关的EST序列设计特异性引物,利用3′,5′-RACE技术,从棉花叶片中克隆出GDP-甘露糖-3′,5′-异构酶(GDP-mannose-3′,5′-epimerase,GME)基因,命名为GhGME.基因全长1 467 bp,开放阅读框1 131 bp,编码376个氨基酸,分子量为42.39 6 kDa,等电点pI=6.291.利用荧光定量Real-time RT-PCR方法对棉花根、茎、叶和3种处理下该基因的表达特性进行分析,结果表明,GhGME在根、茎中高水平表达,在叶中表达量较低.在4℃低温和200 mmol/L NaCl处理下该基因表达上调,然而用100μmol/L GA3处理则表现为下调表达.GhGME的不同表达情况暗示该基因可能在棉花抗逆反应中起着重要的作用,为该基因在棉花中抗逆功能和应用研究提供了基础.