PpeKUP1基因在桃果实钾吸收和转运中的功能分析

Potassium (K+) fertilizer application favorably contributes to fruit quality, yield and storage properties. However, molecular mechanisms towards fruit development in relation to K+ nutrition and accumulation are largely rare. In plants, K+ uptake and transport is facilitated by KT/HAK/KUP family transporters. Functional studies of this family genes are limited to annual plants themselves, while mechanisms of K+ uptake and transport during fruit development, especially of perennial woody crops, are still unknown. In this proposal, we identified and isolated 16 KT/HAK/KUP transporter genes in peach. Through gene expression profiles and tissue-expression pattern analysis, fruit-specific gene PpeKUP1 had been chosen as candidate gene. Test of K+ fertilizer application will proceed to investigate the fruit quality and response characteristics of PpeKUP1 during different fruit development stages. Further tissue, cell and sub-cell localization and functional analysis of bacterial expression will help to reveal the possible role and regulation mechanisms of PpeKUP1 in K+ uptake and transport of peach fruits. Then, PpeKUP1 will be introduced into tomato materials to determine its practical effect in improving crop nutrition, fruit development and quality. This research will directly reveal a close relationship between K+ nutrition, fruit development and quality formation, and favorably provide a theoretical basis for K fertilization in orchards and genetic improvement and breeding of efficient horticulture crops.

果园施用钾肥可有效提升果实品质和产量，改善采后贮藏性能。然而，有关果实发育与钾素营养及受其调控的分子机理报道鲜少。植物KT/HAK/KUP家族基因编码钾转运体蛋白，功能研究仅限于一年生植物体本身，关于果实（尤其多年生木本作物）发育过程中K+吸收与转运分子机制依然未知。本项目在桃基因组数据库获得16个KT/HAK/KUP家族基因；通过表达谱和组织表达分析，筛选到果实特异性表达的PpeKUP1基因；将进一步设置钾肥试验，分析其在果实发育过程中对钾肥施用的响应；通过组织、细胞、亚细胞定位和细菌表达系统探讨其在果实发育中可能的作用及调控机理；通过农杆菌介导转化获得PpeKUP1基因超量表达的转基因番茄株系，评价该基因超量表达后对番茄植株钾素营养、果实发育及品质形成的实际效果。从分子层面探讨钾素营养与果实发育及品质之间的直接关系，为果树施钾及高效园艺作物的遗传改良与育种提供理论依据。

果园施用钾肥可有效提升果实品质和产量，改善采后贮藏性能。然而，有关果实发育 与钾素营养及受其调控的分子机理报道鲜少。植物KT/HAK/KUP家族基因编码钾转运体蛋白 ，功能研究仅限于一年生植物体本身，关于果实（尤其多年生木本作物）发育过程中K+吸 收与转运分子机制依然未知。本项目在桃基因组数据库获得16个KT/HAK/KUP家族基因；通 过表达谱和组织表达分析，筛选到果实特异性表达的PpeKUP1基因；钾肥试验表明不同钾肥施放均显著改善了桃果实的内在品质，PpeKUP1在果实发育过程中持续受钾肥施用的上调作用；组织定位表明其在桃树不同组织部位均有表达，细胞定位表明其在叶片的栅栏组织和维管束韧皮部细胞和根部的皮层和维管束韧皮部细胞，亚细胞定位表明其在细胞质膜；细菌表达系统验证表明其在中性pH环境中具有吸收外界钾离子的功能，是桃果实中（特别是在果实发育初期）维持果实钾素动态平衡的一个重要的钾离子转运体；通过农杆菌介导转化获得PpeKUP1基因超量表达的转基因番茄，该基因超量表达后，增强番茄植株的生长表现、钾素营养状况和果实内在品质形成。本研究从分子层面探讨钾素营养与果实发育及品质之间的直接关系，为果树施钾及高效园艺作物的遗传改良与育种提供理论依据。