橡胶树葡萄糖转运蛋白(HbGLUTs)基因家族的鉴定与分析

Identification and analysis of glucose transporter proteins (HbGLUTs)gene family in rubber tree

关键词:  橡胶树, HbGLUTs, 结构特征, 理化特性, 表达模式

Key words:  rubber tree(Hevea brasiliensis), HbGLUTs, structural features, physicochemical properties, expression pattern

摘要:

葡萄糖不仅是生物体基本的能源物质,同时作为前体物质参与各种合成代谢,其转运蛋白(GLUT)可调节生物体内葡萄糖含量,在维持葡萄糖稳态系统中发挥重要作用。目前,橡胶树中GLUT家族的功能及其在糖稳态、胶乳再生等关键生物学过程中的作用尚未明晰。因此,该研究采用生物信息学方法鉴定橡胶树的GLUT,并对该基因家族成员理化性质、蛋白结构、保守基序、系统发育、顺式作用元件结构特征和基因表达模式进行了系统的分析。结果表明:(1)鉴定到31个HbGLUTs家族成员(HbGLUT1-HbGLUT31),均定位于细胞膜,跨膜结构域数目为9～24(HbGLUT1和HbGLUT2均含24个),二级结构以α螺旋为主。(2)进化分析显示,HbGLUTs与人类GLUTs功能分类相似,Ⅰ亚型(如HbGLUT8和HbGLUT15)具有保守的己糖转运功能,在胶乳再生中通过快速补给葡萄糖维持产胶稳态; 推测Ⅱ亚型、Ⅲ亚型进化出对果糖和肌醇等底物的多样转运能力,其中Ⅲ亚型成员(如HbGLUT3、HbGLUT17和HbGLUT18)在多种组织中高表达且启动子含胁迫相关元件,表示其参与植物抗逆响应。(3)组织特异性表达显示,胶乳中HbGLUTs整体低表达,但Ⅰ亚型部分基因对胶乳再生至关重要,而多个成员(如HbGLUT21和HbGLUT28等)在花中特异高表达,进而支持生殖过程的高能量需求。该研究为解析HbGLUTs在胶乳再生及抗逆中的功能提供了重要线索,为后续进一步研究橡胶树中糖转运蛋白的功能奠定了基础。

Abstract:

Glucose is not only the basic energy source for organisms but also serves as a precursor in various synthetic metabolic processes. Glucose transport proteins(GLUTs)can regulate glucose levels within organisms and play a crucial role in maintaining glucose homeostasis. Currently, the functions of the GLUT family in rubber trees(Hevea brasiliensis)and their roles in key biological processes such as sugar homeostasis and latex regeneration remain unclear. Therefore, this study employed bioinformatics methods to identify GLUTs in rubber trees and systematically analyzed the physicochemical properties, protein structures, conserved motifs, phylogenetic development, cis-acting element structural features, and gene expression patterns of the gene family members. The results were as follows:(1)A total of 31 members of the HbGLUTs family members(HbGLUT1-HbGLUT31)were identified, all located in the cell membrane, with the number of transmembrane domains ranging from 9 to 24(both HbGLUT1 and HbGLUT2 contained 24 transmembrane domains), and the secondary structure was primarily composed of α-helix.(2)Evolutionary analysis revealed that HbGLUTs were functionally similar to human GLUTs in terms of classification. Type I subfamily members(such as HbGLUT8 and HbGLUT15)had conserved hexose transport functions and maintained latex production homeostasis by rapidly supplementing glucose during latex regeneration; it is speculated that Type Ⅱ and Type Ⅲ subfamily members evolved diverse transport capabilities for substrates such as fructose and myo-inositol. Among them, Type Ⅲ subfamily members(such as HbGLUT3, HbGLUT17, HbGLUT18)were highly expressed in various tissues, and their promoters contained stress-related elements, indicating their involvement in plant stress responses.(3)Tissue-specific expression analysis showed that HbGLUTs were generally expressed at low levels in latex, but some genes of Type I subfamily were crucial for latex regeneration. Additionally, several members(such as HbGLUT21 and HbGLUT28, etc.)were highly expressed specifically in flowers, supporting the high energy requirements of the reproductive process. This study provides important clues for elucidating the functions of HbGLUTs in latex regeneration and stress responses, laying a foundation for further research on sugar transport proteins in rubber trees.