檀香小G蛋白Rac1基因的克隆与功能分析  

Cloning and Functional Analysis of SaRac1 Gene in Santalum album Linn.

作　　者：卞展 刘小金[1] 洪舟[1] 张宁南[1] 孟森 徐大平[1] BIAN Zhan;LIU Xiaojin;HONG Zhou;ZHANG Ningnan;MENG Sen;XU Daping(Key Laboratory of Forestry and Grassland Administration on Tropical Forestry, Chinese Academy of Forestry, Guangzhou 510520, China)

机构地区：[1]中国林业科学研究院热带林业研究所,国家林业和草原局热带林业研究重点实验室,广州510520

出　　处：《西北植物学报》2021年第1期46-51,共6页Acta Botanica Boreali-Occidentalia Sinica

基　　金：中国林科院基本科研业务费(CAFYBB2019QB003);国家自然科学基金(31901304);广东省自然科学基金(2019A1515011595)。

摘　　要：植物Rac蛋白属于小分子G蛋白ROP家族,广泛参与活性氧(ROS)产生、激素信号转导和组织形态建成。檀香(Santalum album Linn.)是著名的珍贵树种,为半寄生植物,其正常生长需要根部特化的吸器从其他寄主植物摄取营养物质。该研究基于全长转录组数据,采用RT-PCR方法克隆得到了1个檀香Rac基因,命名为SaRac1。结果表明:(1)SaRac1基因全长594 bp,编码197个氨基酸,分子量21.55 kD,理论等电点9.32,为亲水性蛋白。(2)进化分析显示,SaRac1蛋白和拟南芥(Arabidopsis thaliana)AtRac1~6、AtRac9和AtRac11蛋白同属于典型的植物RacⅠ家族蛋白。(3)结构预测显示,该蛋白在N端为保守的G结构域,蛋白C端具有CaaL保守基序。(4)原生质体亚细胞定位试验显示,SaRac1蛋白定位于细胞核和细胞质。(5)组织特异性表达分析显示,SaRac1基因在根和吸器中表达量最高,幼叶和茎中表达量较高,在成熟叶和老叶中表达量较低。(6)用寄生植物吸器诱导因子2,6-二甲氧基对苯醌(DMBQ)处理,发现SaRac1受到DMBQ的强烈诱导,表达量在4 h达到最高。研究推测,SaRac1基因受吸器诱导因子调控进而参与檀香吸器形成过程。Rac proteins of plants belong to Rho-related GTPase family(ROP family)and play important roles in reactive oxygen species(ROS)production,hormone signal transduction and tissue morphogenesis.Sandalwood(Santalum album Linn.)is a precious and semiparasitic plant with specialized root haustoria to absorb nutrients from other host plants.Based on the full-length transcriptome data,a Rac protein gene was isolated from Santalum album by RT-PCR and named SaRac1.The results showed that:(1)SaRac1 contains a 594 bp opening reading frame,encoding a putative hydrophilic protein of 197 amino acids with molecular weight 21.55 kD and isoelectric point 9.32.(2)Phylogenetic tree analysis showed that the amino acid sequence exhibits high similarity to AtRac1-6,AtRac9 and AtRac11 in Arabidopsis thaliana and belongs to typical Rac I proteins in plants.(3)Sequence alignment indicated the protein has conserved G domains in the N-terminal and CaaL motif in the C-terminal.(4)Subcellular localization analysis showed that SaRac1 localized in the nucleus and cytoplasm.(5)Tissue-specific expression analysis revealed that the transcript level of SaRac1 was higher in roots and haustoria than those in other issues.(6)SaRac1 was induced by 2,6-dimethoxy-ρ-benzoquinoe(DMBQ,an important haustorium-inducing factor)and reached the highest transcript level at 4 h.These results indicate that SaRac1 might be induced by the chemical factor and involved in the development of haustorium.

关 键 词：寄生 檀香 SaRac1 基因克隆 

分 类 号：Q785[生物学—分子生物学] Q786