脱落酸代谢途径与信号转导关键基因调控樱桃和番茄果实成熟分子机制的研究

发布时间：2018-05-11 08:09

本文选题：脱落酸 + 果实成熟　；参考：《中国农业大学》2017年博士论文

【摘要】：果实是果树类园艺作物的重要经济器官,是人们日常饮食的重要组成部分和营养物质来源。但是由于果实的成熟与衰老无法有效的控制,导致果品在生产、贮藏和流通过程中造成巨大的经济损失和资源浪费。因此,我们应该积极开展对果实成熟衰老的生理生化及其分子机制的研究,探索调控果实成熟和延长货架期的有效方法,以满足人们对高质量果品供应的需求。脱落酸(ABA)是重要的植物激素,在果实成熟过程中起着十分重要的调控作用。然而ABA对果实成熟调控机制还缺少分子水平的证据。本文以非呼吸跃变型果实樱桃和跃变型果实模式植物番茄为试材,利用基因沉默技术,研究了 ABA代谢与信号转导途径关键基因对果实成熟的调控作用,为阐明ABA调控果实发育的分子机制提供了大量证据。取得的主要结果如下:1.本文利用病毒诱导的基因沉默(VIGS)技术鉴定了樱桃果实中ABA降解途径关键酶ABA 8'-羟化酶基因PacCYP707A1的功能。PacCYP707A1沉默的樱桃果实成熟过程没有受到影响,ABA代谢基因与花青素合成基因的表达也没有明显的变化。但是在离体果实失水的过程中,PacCYP707A1-VIGS果实积累更高水平的ABA,导致果实的失水率降低。这些结果表明PacCYP707A1调控果实的内源ABA含量进而影响樱桃离体果实的失水率。2.本研究利用VIGS鉴定了番茄果实中ABA生物合成关键酶9-顺式-环氧类胡萝卜素双加氧酶基因SlNCED1与ABA 8'-羟化酶基因SlCYP707A2的功能。研究发现,SlNCED1与SlCYP707A2是调控番茄果实ABA合成与降解的关键基因,且对果实成熟分别具有正调控和负调控作用。这些结果表明通过ABA的生物合成与降解途径调控果实中ABA的含量可以影响番茄果实的成熟。3.本研究利用RNA干扰(RNAi)技术研究了番茄中ABA葡萄糖基转移酶基因SlUGT75C1的生理功能。SlUGT75C1沉默的番茄果实中ABA含量升高而ABA-GE的含量降低,表明SlUGT75c1能在植物体内通过ABA糖基化途径调控ABA的内稳态。SlUGT75C1-RNAi果实由于ABA含量的升高导致成熟提前,但果实中类胡萝卜素的含量降低。这些结果表明SlUGT75C1介导的ABA糖结合途径在调控的果实成熟过程中起着重要的作用。4.本文筛选出了参与番茄ABA信号转导的关键2C型蛋白磷酸酶成员S1PP2C3。利用RNAi在植株中抑制SlPP2C3的表达导致植株在种子休眠与萌发、幼苗初生根生长,响应干旱胁迫等方面都表现出典型的ABA高度敏感表型,表明S1PP2C3是番茄ABA信号的负调控因子。SlPP2C3-RNAi番茄果实成熟显著提前,且乙烯释放量明显升高。通过基因表达分析发现S1PP2C3可能通过调节乙烯合成基因ACOs与乙烯受体基因ETRs的表达调控果实成熟。此外,转录组数据表明S1PP2C3介导的ABA信号可能参与调控果实的角质层形成。综上所述,本研究证明了樱桃与番茄中多个ABA代谢途径与信号转导关键基因对果实的成熟具有重要的调控功能,同时证明了通过生物技术操纵ABA相关基因调控果实成熟和品质的可能性。本研究的结果为揭示果实发育与成熟调控网络奠定了基础,为人工调控果实的成熟提供了理论基础,也为通过定向分子育种改良果品提供了新思路。
[Abstract]:Fruit is an important economic organ of fruit tree horticultural crops. It is an important part of people's daily diet and a source of nutrients. However, due to the failure of the fruit to be effectively controlled, the fruit can cause huge economic loss and waste of resources in the process of production, storage and circulation. Therefore, we should actively carry out the problem. The physiological, biochemical and molecular mechanisms of fruit ripening and senescence are studied to explore effective methods to regulate fruit maturity and prolong shelf life to meet the demand for high quality fruit supply. Abscisic acid (ABA) is an important plant hormone and plays a very important regulatory role in fruit ripening. However, ABA is a regulatory machine for fruit ripening. In this paper, there is no evidence of molecular level. In this paper, the control effect of key genes of ABA metabolism and signal transduction pathway on fruit ripening was studied by using gene silencing technique. A lot of evidence was provided to elucidate the molecular mechanism of controlling fruit development by ABA. The main results are as follows: 1. in this paper, the virus induced gene silencing (VIGS) technique was used to identify the key enzyme of ABA degradation pathway ABA 8'- hydroxylase gene PacCYP707A1 in cherry fruit. The maturation process of cherry fruit ripening was not affected by the function of.PacCYP707A1 silencing, and the expression of the ABA metabolic gene and anthocyanin synthesis gene was not obvious. But in the process of water loss in the isolated fruit, the PacCYP707A1-VIGS fruit accumulates a higher level of ABA, which leads to the decrease of the water loss rate of the fruit. These results show that PacCYP707A1 regulates the endogenous ABA content of fruit and then affects the water loss rate of cherry in vitro.2.. This study used VIGS to identify the key enzyme of the key enzyme of ABA biosynthesis in tomato fruit, 9- The function of CIS CIS carotenoid bioxygenase gene SlNCED1 and ABA 8'- hydroxylase gene SlCYP707A2. It is found that SlNCED1 and SlCYP707A2 are key genes regulating the synthesis and degradation of tomato fruit ABA, and have positive regulation and negative regulation on fruit ripening. These results show that the biosynthesis and degradation routes of ABA are carried out. The content of ABA in fruit can affect the mature.3. of tomato fruit. The study of RNA interference (RNAi) technique to study the physiological function of ABA glucosyltransferase gene SlUGT75C1 in tomato, the content of ABA in tomato fruit with.SlUGT75C1 silencing is increased and the content of ABA-GE decreased, indicating that SlUGT75c1 can be carried through ABA glycosylation in plants. The endogenous.SlUGT75C1-RNAi fruit of ABA regulated the maturity of the fruit due to the increase of ABA content, but the content of carotenoid in the fruit decreased. These results showed that the SlUGT75C1 mediated ABA sugar binding pathway played an important role in the regulation of fruit ripening,.4. this paper screened the key to participate in the signal transduction of tomato ABA. The 2C type protein phosphatase member S1PP2C3. uses RNAi to inhibit the expression of SlPP2C3 in the plant, resulting in the seed dormancy and germination, the growth of the primary root of the seedlings, and the typical ABA highly sensitive phenotype in response to drought stress, which indicates that S1PP2C3 is a negative regulating factor of the ABA signal of tomato, and the fruit maturity of the tomato is significantly advanced in advance. By gene expression analysis, S1PP2C3 may regulate fruit ripening by regulating the expression of ethylene synthesis gene ACOs and ethylene receptor gene ETRs. In addition, the transcriptional data indicate that S1PP2C3 mediated ABA signals may be involved in regulating the formation of the cuticle in fruit. Multiple ABA metabolic pathways and key signal transduction genes in tomatoes have important regulatory functions on fruit ripening. At the same time, the possibility of regulating fruit maturity and quality by manipulating ABA related genes through biotechnology has been proved. The results of this study have laid a foundation for revealing the fruit development and maturation control network and for artificial regulation of fruit. Maturity provides a theoretical basis, and provides a new way of improving fruit by directional molecular breeding.

【学位授予单位】：中国农业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：S641.2;S662.5

【参考文献】