香蕉MaOFP介导的MuMADS1对果实成熟及品质形成的调控机制

Banana is one of the most important tropical fruits in the world.Regulation of postharvest banana fruit ripening and quality formation is the key science and technology problem which decides the sustainable and healthy development of banana industry. However, the regulatory mechanism of fruit ripening and quality formation remains unclear. MADS-box transcriptional factors played important roles in fruit ripening and quality formation. Investigating the molecular mechanism of MADS-box transcriptional factor and other transcriptional factors' interaction is an effective way to solve this problem. Evidence we obtained under the previous National Natural Science Fundation of China (NNSFC) project supported showed that banana MuMADS1 interacted with an Ovate Family Protein named MaOFP(Musa acuminata Ovate Family Protein). This project is going to further investigate the molecular mechanism of MuMADS1 and MaOFP interaction , confirm the regulatory role of MaOFP-mediated MuMADS1 on fruit quality formation and investigate the transcriptome changes in over-expressed MuMADS1 and MaOFP fruits under mutant background by molecular biology and molecular genetics methods. The functions of genes transcriptionally regulated by MaOFP-mediated MuMADS1 were analysed. The purpose of this project is to understand the regulatory mechanism of transcriptional factors for fruit quality formation. These findings will provide theoretical basis for improving banana fruit quality through regulating the expressions of MuMADS1 and MaOFP by molecular biology and genetic engineering methods and also provide reference for genetic improvement of other horticultural plants whose harvest objects are fruits.

香蕉是世界重要热带水果，果实采后成熟及品质形成调控是决定香蕉产业可持续健康发展的关键科技问题，但目前其形成调控的机制不明。MADS-box在果实成熟及品质形成中具有重要作用，研究MADS-box转录因子与其它转录因子互作的分子机制是解决这一问题的有效途径之一。我们在前基金资助下获得的证据表明：香蕉MuMADS1与MaOFP相互作用。本项目采用分子生物学和分子遗传学手段研究MuMADS1与MaOFP互作的分子机制，研究MaOFP介导的MuMADS1对果实品质的调控作用，研究在突变体背景下MuMADS1与MaOFP过表达果实中转录组的变化，分析MaOFP介导的MuMADS1所转录调控的基因的功能，阐明果实品质形成过程中转录调控因子的作用机制。研究结果将为进一步采用分子生物学和基因工程手段通过调控这些位点而达到改善香蕉果实品质提供理论依据，也为其它以果实为收获对象的园艺植物品质改良提供借鉴作用。

香蕉是世界重要热带水果，果实采后成熟及品质形成调控是决定香蕉产业可持续健康发展的关键科技问题，但目前其形成调控的机制不明。MADS-box在果实成熟及品质形成中具有重要作用，研究MADS-box转录因子与其它转录因子互作的分子机制是解决这一问题的有效途径之一。我们在前基金资助下获得的证据表明：香蕉MuMADS1与MaOFP相互作用。本项目采用分子生物学和分子遗传学手段研究MuMADS1与MaOFP互作的分子机制，研究MaOFP介导的MuMADS1对果实品质的调控作用，研究在突变体背景下MuMADS1与MaOFP过表达果实中转录组的变化，分析MaOFP介导的MuMADS1所转录调控的基因的功能，阐明果实品质形成过程中转录调控因子的作用机制。取得的重要研究结果及关键数据如下：1) 是MuMADS1 蛋白的 k-domain 与MaOFP1 发生相互作用。2) MuMADS1 确实能减轻MaOFP1 的转录抑制活性。3) MuMADS1 和MaOFP1 在采后0天的果实中高水平表达，在茎中表达水平最低，说明其在不同的组织和发育的果实中的表达具有协同性。4) 在香蕉采后成熟过程中MuMADS1 的表达受外源乙烯诱导和1 -MCP 的抑制，而MaOFP1 表达却受外源乙烯抑制和1-MCP 的诱导，证明这两个基因拮抗性地调控香蕉果实采后成熟过程。5)构建含MaOFP1 和MuMADS1 的过表达植物表达载体，分别或者两个基因共同转化番茄ovate突变体，获得了令人振奋的结果，那就是MuMADS1 和MaOFP1 互作以后能够补偿ovate突变体果实形状、糖含量及果实硬度等品质劣变的表型。这是在国际上首次将MaOFP1 的功能扩展到了对果实品质的调控上，首次证实了两个互作的转录因子协同调控果实品质的分子机制，拓展了MADS-box 转录因子对果实品质的调控网络, 研究结果发表在国际植物学TOP10 的杂志上(Liu et al., Plant Biotechnology Journal, 2018 )，并申请了国家发明专利保护（一种改良植物果实品质的基因及其编码产物与应用，申请号：2015100597977）。研究结果为进一步采用分子生物学和基因工程手段通过调控这些位点而达到改善香蕉果实品质提供理论依据，也为其它以果实为收获对象的园艺植物品质改良提供借鉴作用。