草莓蔗糖代谢与转运相关基因对果实糖分积累的影响机理

发布时间：2018-05-31 23:10

本文选题：草莓 + 碱性/中性转化酶　；参考：《甘肃农业大学》2017年硕士论文

【摘要】：糖分不仅作为能源物质参与植物生长发育、形态建成,还被认为是一种信号分子响应环境胁迫、调控植物生长发育,进而影响果实品质形成。草莓是世界著名的浆果,果实中糖分积累对品质具有极其重要的影响。本研究通过研究不同草莓品种中糖代谢及转运相关基因与果实糖含量和组分、糖代谢酶活性及与糖含量相关性,及其进化、表达和对多种激素、外源糖及病原真菌的响应,明确其对草莓糖分积累的分子机制。主要结果如下:(1)草莓果实可溶性糖由葡萄糖、果糖和蔗糖构成,其中糖分积累以蔗糖为主;有机酸主要由柠檬酸和苹果酸构成,其中柠檬酸的含量是苹果酸的3-4倍;果实发育过程中蔗糖的积累与碱性/中性转化酶活性呈显著负相关;(2)草莓碱性/中性转化酶基因(Fa.A/N-Invs)家族由8个成员组成,在本研究分析的样品中检测到其中4个成员(Fa.A/N-Inv A,Fa.A/N-Inv B,Fa.A/N-Inv C,Fa.A/N-Inv E)转录表达;(3)Fa.A/N-Invs在各个组织中均有表达,成熟叶片中表达最显著,表明碱性/中性转化酶能够参与植物多种发育过程;果实发育过程中,Fa.A/N-Invs表达模式与酶活性变化吻合,说明该家族基因转录水平的调控是果实品质调节的重要环节之一;(4)Fa.A/N-Invs能响应外源IAA、GA和6-BA;在蔗糖碱性/中性转化酶酶促反应中,蔗糖和葡萄糖分别作为底物和产物,对Fa.A/N-Invs表达起促进和反馈抑制作用,蔗糖类似物松二糖也能诱导Fa.A/N-Invs差异表达,说明草莓碱性/中性转化酶基因参与多种激素和糖分相关信号通路;(5)草莓叶片受炭疽病病原菌C.fructicola侵染后Fa.A/N-Invs的表达量上调、A/N-Inv活性升高,其中Fa.A/N-Inv B/E对病原菌的早期响应最敏感,说明草莓碱性/中性转化酶能通过影响碳水化合物分配参与草莓对病原真菌的防卫响应;(6)"红颜"果实自白果期开始蔗糖含量迅速增加,"申阳"果实蔗糖积累缓慢,果实成熟时"红颜"果实蔗糖含量(50.74mg·g-1FW)约为"申阳"果实的2倍(23.18mg·g-1FW),进行蔗糖转运蛋白家族基因(FaSUTs)的表达分析表明,"红颜"草莓随着果实发育FaSUT1、FaSUT6的表达量呈现上升趋势,FaSUT2稳定表达,FaSUT7仅在成熟果实中表达,"申阳"草莓中FaSUTs在成熟果实中几乎不表达,说明FaSUT1-2、FaSUT6-7在成熟期果实的转录表达差异可能是导致两个品种果实蔗糖含量差异的原因之一。本研究表明:草莓碱性/中性转化酶在幼果期通过分解光合产物促进碳水化合物再分配进而影响果实发育;果实进入膨大期碱性/中性转化酶活性下降,果实糖分开始迅速积累;果实成熟时,蔗糖代谢酶净活性趋于零,蔗糖转运蛋白家族基因转录产物积累上调,调控果实蔗糖输入,促进果实蔗糖积累。
[Abstract]:Sugar not only participates in plant growth and morphogenesis as energy material, but also is considered as a signal molecule in response to environmental stress, regulating plant growth and development, and then affecting fruit quality formation. Strawberry is a famous berry in the world. The accumulation of sugar in the fruit has an extremely important effect on the quality. In this study, we studied the relationship between sugar metabolism and transport related genes, sugar content and components, activities of sugar metabolism enzymes and their correlation with sugar content, their evolution, expression and response to many hormones, exogenous sugar and pathogenic fungi in different strawberry varieties. The molecular mechanism of sugar accumulation in strawberry was clarified. The main results are as follows: (1) the soluble sugar in strawberry fruit is composed of glucose, fructose and sucrose, the sugar accumulation is mainly sucrose, the organic acid is mainly composed of citric acid and malic acid, the content of citric acid is 3-4 times that of malic acid. There was a significant negative correlation between the accumulation of sucrose and alkaline / neutral invertase activity during fruit development. (2) Strawberry alkaline / neutral invertase gene (Fa.A / N-Invs) family was composed of eight members. Four members of Fa.Ar N-Inv Fa.ArN-Inv / Fa.Ar / N-Inv / Fa.ArN-Inv / Fa.ArN-Inv Evs were found to be expressed in all tissues, and the most significant expression was found in mature leaves, indicating that alkaline / neutral invertase can participate in many plant development processes. During fruit development, the expression pattern of Fa.A / N-Invs coincided with the change of enzyme activity, which indicated that the regulation of transcription level of genes in this family was one of the important links in fruit quality regulation, and Fa.ArN-Invs could respond to exogenous IAAGA and 6-BA.In the enzymatic reaction of sucrose alkaline / neutral invertase, Sucrose and glucose, as substrates and products, promoted and inhibited the expression of Fa.A/N-Invs, and sucrose analogue, loose disaccharide, also induced differential expression of Fa.A/N-Invs. The results showed that alkaline / neutral invertase gene was involved in many hormone and sugar related signaling pathways. (5) the expression of Fa.A/N-Invs in strawberry leaves was up-regulated by anthracnose pathogen C.fructicola, and Fa.A/N-Inv B / E was the most sensitive to the early response of the pathogen. The results showed that alkaline / neutral invertase could participate in the defense response of strawberry to pathogenic fungi by affecting carbohydrate distribution. The sucrose content of "Hongyan" fruit increased rapidly at the beginning of the fruiting period, but the accumulation of sucrose in "Shenyang" fruit was slow. The sucrose content of "Hongyan" fruit at maturity was about 2 times that of "Shenyang" fruit, and the expression analysis of sucrose transporter family gene FaSUTsshowed that the expression of FaSUT6 in "Hongyan" strawberry increased with the development of fruit. The stable expression of FaSUT2 was only expressed in mature fruit, but FaSUTs in "Shenyang" strawberry was hardly expressed in mature fruit. It was suggested that the difference of transcription expression of FaSUT1-2 and FaSUT6-7 in mature fruit might be one of the reasons leading to the difference of sucrose content between the two varieties. The results showed that alkaline / neutral invertase promoted carbohydrate redistribution by decomposition of photosynthates in young fruits and decreased the activity of alkaline / neutral invertase at the stage of fruit expansion. The sugar content began to accumulate rapidly and the net activity of sucrose metabolism enzyme tended to be zero when fruit matured. The accumulation of transcription products of sucrose transporter family was up-regulated which regulated the sucrose input and promoted the accumulation of sucrose in fruit.
【学位授予单位】：甘肃农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S668.4

【相似文献】