苹果糖转运蛋白TMT基因的表达及其与糖积累的关系

Sequence and Expression Analysis of Apple Tonoplast Monosaccharide Transporter TMT Genes and Their Relationship with Sugar Accumulation in Fruit

利用苹果基因组筛选液泡膜单糖转运蛋白TMT家族基因,通过qRT-PCR探索它们在苹果各器官组织中的表达特性,并分析其表达与果实糖积累的关系。结果表明,在苹果中主要存在5个TMT家族基因,均含有11个跨膜区,并具有1个长约330氨基酸的亲水loop区位于胞质内,它们与拟南芥和葡萄的TMTs高度同源。定量表达分析发现,它们均在苹果中表达,且MdTMT1表达量相对最高,MdTMT3和MdTMT4表达量较低。MdTMT1在花和成熟果实中表达量最高,MdTMT2在成熟果实中表达最高。在果实发育过程中,MdTMT1和MdTMT2的表达量与果实中总糖、还原性总糖、果糖、蔗糖含量呈极显著正相关,说明MdTMT1和MdTMT2可能参与了苹果果实成熟期果糖和蔗糖的积累。

In present study,we analyzed the information of apple tonoplast monosaccharide transporter(TMT)gene family based on Malus genome database,and explored their expression characteristics by qRT-PCR and analyzed the relationship between their expression and sugar accumulation in apple. The results showed that apple had 5 transcribed MdTMT genes with 11 transmembrane domains and a hydrophilic loop located in the cytoplasm. These MdTMTs are highly homologous with Arabidopsis thaliana and Vitis vinifera TMTs. Quantitative expression analysis showed that all MdTMTs were expressed in apple with a higher expression abundance of MdTMT1 and lower expression abundance of MdTMT3 and MdTMT4. MdTMT1 had the highest expression abundance in flower and fruit while MdTMT2 in fruit. The expression of MdTMT1 and MdTMT2 had significantly positive correlation with total sugar,reducing sugar,fructose and sucrose during fruit development,especially MdTMT2. These results suggested that MdTMT1 and MdTMT2 may participate in the accumulation of fructose and sucrose in the fructescence of apple.