阳春砂果实发育过程中可溶性糖及蔗糖代谢酶活性变化规律的研究

摘要

This study was aimed to discuss the dynamic variation of soluble sugar contents, sucrose metabolizing en-zyme activities and gene expression quantities during the fruits development of A momum villosum, in order to pro-vide the basis of improvement of the fruit yield. Fresh fruits at three different development processes (30 DAF, 60 DAF, 90 DAF) were used to investigate changes of soluble sugar components and sucrose metabolizing enzyme activ-ities by HPLC and UV spectrophotometry. Combining with the high-throughput sequencing expression profile data of three fruit development period, the trends of three key enzymes gene expressed in sugar metabolism were analyzed. The results showed that the fruit sugar components were dominated by fructose, glucose and sucrose. The concentra-tion of hexose (fructose and glucose) gradually decreased in peel. But in seeds the concentration of hexose decreased at first and then increased. The content of sucrose and the net activities of sucrose synthase (synthesizing direction minus decomposing direction) in peel and seeds were gradually increased. The expression trends of key enzyme gene in sugar metabolism examined by RNA-seq quantification showed that sucrose phosphate synthase and sucrose syn-thase gene increased and then kept constant, but the invertase gene expression trend was gradually rising. Conse-quently, sucrose synthase was the key enzyme catalyzing sucrose synthesis and decomposition. The activity of sucrose synthase and sucrose contents in peel and seeds reached the highest peak in the end of fruit mature.%目的：为研究阳春砂果实发育过程中可溶性糖含量、蔗糖代谢酶活性和基因表达量的动态变化规律，并为提高阳春砂的产量提供依据。方法：本研究以阳春砂幼果期、成熟中期和成熟末期的新鲜果实为试验材料，采用高效液相色谱法、紫外分光光度法对可溶性糖含量和酶活性进行测定，并结合3个发育时期果实的高通量测序表达谱数据，分析糖代谢中3个关键酶基因的表达趋势。结果：果糖、葡萄糖和蔗糖是阳春砂果实中的主要糖分，在果实发育过程中，果皮中的己糖（果糖和葡萄糖）含量逐渐降低，种子团中己糖含量先降低后升高；果皮和种子团中蔗糖含量和蔗糖合成酶净活性（合成方向减去分解方向活性）均逐渐升高。结论：基于RNA-seq的糖代谢中的关键酶基因表达趋势分析表明，蔗糖磷酸合成酶、蔗糖合成酶基因的表达趋势以先上升后不变为主，转化酶基因的表达趋势以逐渐上升为主。蔗糖合成酶是催化阳春砂果实中蔗糖合成与分解的关键酶，果实成熟末期是蔗糖合成酶活性和蔗糖含量最高的时期。