菌根化马尾松磷转运蛋白家族基因的生物信息学和表达分析

利用同源克隆法从菌根化马尾松中获得14条磷转运蛋白基因片段,对其中6条(PmP1~PmP6)编码的氨基酸序列进行了比对和同源性分析,检测了不同磷水平下各成员的表达模式.结果表明,PmP1~PmP6编码氨基酸序列具有Pht1磷转运蛋白家族的典型特征,成员间相似性达70%以上.系统分析表明,它们分为5个亚组,与双子叶植物的同源性较高,且高度进化保守.综合分析半定量和荧光定量PCR结果显示,PmP1~PmP6的表达受外生菌根诱导,且根、茎和针叶中均有表达.未接种菌根真菌时,PmP1~PmP6在针叶中表达量最高,其次为根;接种后,根中表达活性升高,其表达量与生长环境中磷水平相关,低磷条件下被高效激活,高磷条件反而抑制其表达.因此,PmP1~PmP6参与菌根化马尾松体内磷的吸收和转运过程.

Bioinformatic and Expression Analyses of the Ectomycorrhizal Phosphate Transporter Gene in Pinus massoniana

In this study, 14 fragments of the ectomycorrhizal masson pine (Pinus massoniana) phosphate transport protein gene (PmPs) were obtained using the homologous cloning method, of which 6 (PmP1~PmP6) were used to carry out homology analysis based on their amino acid sequences. Subsequently, their expression patterns were characterized by the semi-quantitative and quantitative PCR technology. The results showed that the amino acid sequences of PmP1~PmP6, which were highly homologous at the amino acid level with over 70% identity, had a typical structure of the members of the Pht1 family. Phylogenetic analysis indicated that they might be distinctly divided into five subgroups and demonstrated that they were highly homologous with dicotyledons, reflecting the considerably strict conservation during the evolutionary process. Semi-quantitative and quantitative PCR suggested that the expression of PmP1~PmP6 might be induced by the ectomycorrhizal fungi (ECM), which were expressed in the leaf, the stem and the root. Their expression level in the leaf was significantly higher than that in the stem or root in ECM-free plants. However, a high expression of PmP1~PmP6 was observed in the ECM-inoculated roots, as compared with the non-inoculated control. Additionally, the expression of PmP1~PmP6 was related to the phosphorus status of the soil, and their expression was intensively activated by low phosphorus; in contrast, a high level of phosphorus inhibited the expression of these genes. In conclusion, PmP1~PmP6 might be involved in phosphorus uptake and transport in ECM-inoculated masson pine, which facilitated the understanding of phosphorus absorption as promoted by ectomycorrhiza.