毛果杨全基因组磷酸根转运蛋白家族成员序列分析

Genome-wide analysis of the phosphate transporter gene family in Populus trichocarpa

磷酸根转运蛋白是一类主动转运磷酸根的重要载体蛋白。主要探讨毛果杨Populus trichocarpa全基因组中磷酸根转运蛋白(phosphate transporter)家族成员的系统发生和部分成员的理化性质、结构特点及亚细胞定位。以从毛果杨全基因组数据库中搜索并筛选得到的目标蛋白序列为基础,利用相关生物信息学软件对其进行系统发育分析,并利用一系列在线服务器对部分成员的理化参数、亲/疏水性、跨膜域、二级结构、三级结构和亚细胞定位进行了重点分析。结果表明,在毛果杨全基因组中共发现了31个磷酸根转运蛋白家族成员,根据其序列相似性,可分为4个亚家族,即PtrPHT1,PtrPHT2,PtrPHO1和PtrPHO2;PHT亚家族内的序列相似性高于PHO,并且高度保守;它们均为疏水性的全α型蛋白质,PHTs一般具有12个跨膜域,多于PHOs;不同亚家族成员的亚细胞定位不尽相同。因此,毛果杨磷酸根转运蛋白不同亚家族间分开较早,它们在杨树磷素代谢中可能起着不同的作用,共同维持并调控杨树体内的磷素平衡。

Phosphate transporters are a family of proteins which actively transport phosphate. To investigate members of phosphate transporter family and their physical, chemical and structural properties in the woody model Poptdus trichocarpa, phylogenesis of the phosphate transporter family members and their physical, chemical, structural properties as well as sub-cellular locations of four phosphate transporters （PtrPHTI-1, PtrPHT1-9, PtrPHT2-I, and PtrPHO1-N1 ） from the sequenced genome of Populus trichocarpa were studied. A phylogenetic analysis of the transporters was conducted using local bioinformatics software, such as CLUSTALX 2.0, GeneDOC, and MEGAS. In addition, online bioinformatics software was utilized to analyze the physical and chemical properties, hydrophilicity/hydrophobicity, transmembrane domains, secondary and three-dimensional structures, and sub-cellular locations. Results showed 31 phosphate transporters in the P.trichocarpa genome divided into four subfamilies （PtrPHT1, PtrPHT2, PtrPHO1, and PtrPHO2） according to their sequencing similarities. The sequence identity of amino acids within PtrPHT＇s was higher than in PtrPHO＇s, and was highly conserved. The transporters were hydrophobic α-protein. Also, PtrPHT＇s contained 12 transmembrane domains which were more than the PtrPHO＇s with the PtrPHT family members being located at different sub-cellular locations. Therefore, phosphate transporter subfamilies in P. trichocarpa could have separated in an early stage during their evolutionary processes, and these transporters could have played dif- ferent roles in phosphorus metabolism to maintain phosphorus homeostasis for changing phosphorus conditions. [Ch, 6 fig. 4 tab. 17 ref.]