二穗短柄草谷氨酸类受体系统发生学和基因表达分析

The Phylogeny and Expression Analysis of Glutamate Like Receptor Gene in Brachypodium distachyon

二穗短柄草基因组已被测序,与麦类作物和牧草近缘。二穗短柄草作为温带禾本科模式植物,有很多重要基因序列结构、进化信息等需要进一步挖掘。以拟南芥AtGLRs氨基酸序列为种子序列,利用Phytozome数据库中Blast工具,获得19个二穗短柄草谷氨酸受体候选序列。基于谷氨酸受体氨基酸序列构建系统发生树,结果显示,BdGLRs与AtGLRs聚类距离较近,亲缘关系较好。将20个AtGLRs和19个BdGLRs分别构建系统发生树,拓扑结构类似,均分为3枝,表明BdGLRs也有3个亚家族。参考AtGLRs的分类和命名规则,将BdGLRs分为3类,分别命名为BdGLR1.1-1.4、BdGLR2.1-2.10和BdGLR3.1-3.5。通过半定量和定量反转录PCR分析发现在三叶期,BdGLR家族各成员表达各异,相同成员在不同组织中表达不同,不同成员在相同组织表达不同。除BdGLR1.4和BdGLR2.6-2.10,其余BdGLRs在根、茎、叶中均有表达。为二穗短柄草的谷氨酸受体基因功能的深入研究提供线索,也为后续禾本科农作物和牧草遗传改良提供理论依据。

Brachypodium distachyon is a temperate gramineae model grass which has a small stature,rapid life cycle,completely sequenced genome,and close relationship with cereals and grasses.There are many moleculer traits and evolution information needed to be explored in Brachypodium distachyon.The plant glutamate like receptors（GLR） participate in some key biological process,such as plant development,stress responses,signalling pathways.However,the GLRs of Brachypodium distachyon were systematically uninvestigated.The 19 predicted Brachypodium glutamate receptor members were identified through Blast search in Phytozome Database based on amino acid sequence of AtGLRs.Phylogenetic tree based on glutamate receptor sequences was constructed,and it found that BdGLRs and AtGLRs were grouped in a large clade.BdGLRs had a close phylogenetic relationship with Arabidopsis.The two phylogenetic trees based on 19 BdGLRs and 20 AtGLRs showed similar topology structures,both of which were divided into 3 clades with 3 subfamilies.They were named respectively as BdGLR1.1-1.4,BdGLR 2.1-2.10 and BdGLR 3.1-3.5 according to their position in the phylogenetic tree and nomenclature of AtGLRs.On the basis of Semi-quantitative and quantitative RT-PCR,in the stage of three leaves,13 BdGLRs were expressed large differently in same and different tissues.Except BdGLR1.4 and BdGLR2.6-2.10.2.8-2.10,all BdGLRs were expressed almost in root,stem and leaves of seedling.The results provided clues to molecular function of BdGLR and might provide theoretical basis for crop and grass improvement.