花生脂质转运蛋白家族基因的克隆与表达分析

Cloning and Expression Analysis of Lipid-transfer Protein Family Genes in Arachis hypogaea L.

植物脂质转运蛋白(Lipid transfer protein,LTP)作为一类小分子碱性蛋白在脂类物质的运输、生殖发育,抵御不良环境等方面具有重要的作用,此外,LTP还作为一种过敏原存在。通过构建花生未成熟种子全长cDNA文库,克隆到了5类LTP基因,按照编码蛋白分子量的大小命名为AhLTP-11.5,AhLTP-12.8,AhLTP-11.8,AhLTP-8.3和AhLTP-19.2。生物信息学预测表明AhLTP-11.5属于AAI_LTSS蛋白家族的nsLTP1亚族,AhLTP-11.5编码蛋白的N端有26个氨基酸残基的信号肽序列,ProtCompv8.0预测结果显示该蛋白为分泌蛋白,胞外定位。从系统发育树中可以看出,花生的AhLTP-11.5和拟南芥的AthLTP亲缘关系较近。半定量RT-PCR结果表明AhLTP-11.5基因在花生茎、叶、花和种子中均有表达,在根中几乎检测不到;在花生种子的不同发育时期AhLTP-11.5基因在DAP15d时表达量较低,20d以后表达趋于稳定。

As a class of small, basic protein, plant lipid transfer protein plays important roles in lipid transportation, plant reproduction and development. It is also an allergen. By constructing a full-length cDNA library derived from immature peanut seeds, five groups of LTP gene were cloned, which were named AhLTP-11.5, AhLTP-12.8, AhLTP-11.8, AhLTP-8.3 and AhLTP-19.2 according to the molecular weight of coding protein. Bioinformatics analysis showed that AhLTP-11.5 belongs to nsLTP1 subfamily of AAI_LTSS family. ProtComp v8.0 results showed that AhLTP-11.5 was a secreted protein and located in the extracellular. The phylogenetic tree showed that AthLTP was closely related to AhLTP-11.5. Semi-quantitative RT-PCR results showed that AhLTP-11.5 expressed in stems, leaves, flowers, seeds while the expression level in root was very low. During seeds development, the expression level of AhLTP-11.5 was low at DAP15 to compare the expression level at DAP20 through DAP45.