YFT1（YELLOW FRUIT TOMATO 1）基因调控番茄果实成熟变软分子机制研究

Fruit firmness is an important index of production quality and economical value in tomato (Solanum lycopersicum), and the firmness was determined by both properties of the primary cell wall and cell turgor. Through previously investigated, we realized that compared with cv.M82 (wild tomato), the hardened fruit in mutant yft1（yellow fruit tomato 1）attributed to variation of the primary cell wall. So far, the studies on morphogenesis of the primary cell wall were insufficiency in plant kingdom, and most of them focused on the hypocotyl in Arabidopsis thaliana. However, the of the tomato fruit with uniqueness development pattern was distinctive different to Arabidopsis thaliana, thus the formation of the primary cell wall to be precise regulation in tomato fruit has remained elusive. Based on the previously researched data including map-based cloning of the YELLOW FRUIT TOMATO 1 (YFT1) and transcriptome analysis in our Lab, design an experiment ethylene treatment, and create the different genetic type tomatoes including mutants, over expression, and over expression(OE) in yft1 background(yft1 OEs). And then the expression of genes associated the primary cell wall of tomato fruit (GTPTs）consisting of SLCEL2、SLCESA6、SLPL and SLEXP1 were analyzed by RT-qPCR technique. Varieties of genetic phenotypes which containing fruit firmness, ultrastructure and chemical compositions consisting of cellulose, hemi-cellulose, pectin and contractual proteins were detected by texture analyzer, semi-quantitative method and HPLC. The expression profile of the GTPTs (SLCEL2、SLCESA6、SLPL and SLEXP1) regulated by YFT1 and changes of the genetic phenotypes would be further dissected in the present proposal. The genetics relationship of upper and follower stream between the YFT1 and GTPTs would be also clarified explicitly. Aim of the project is to reveal mechanism of the fruit softening during mature development in tomato, and would provide important theory evidences for coming improvement of the tomato qualities.

硬度是番茄（S.lycopersicum）品质和经济性状的重要指标，取决于细胞初生壁特征和膨压。我们前期研究发现，yft1（yellow fruit tomato 1）果实变硬主要归因于初生壁改变。植物初生壁形态建成研究还不够深入并主要聚焦于拟南芥下胚轴，番茄果实独特发育模式，果实硬度决定因子初生壁建成的精准调控分子机制还不清楚。基于此，我们在图位克隆YFT1和转录组分析基础上，本项目通过设计乙烯处理实验、创制番茄不同遗传型（突变体、过表达和 yft1 OEs），分析不同遗传背景GTPTs（genes associated the primary cell wall of tomato fruit）表达和遗传表型（硬度、超微结构和化学组分）变化，明确YFT1调控GTPTs表达模式、对遗传表型影响及YFT1与GTPTs遗传调控上、下游关系；以期揭示YFT1调控番茄果实变软分子机制。

果实硬度是番茄（S.lycopersicum）重要品质和经济指标，与细胞初生壁形成和膨压有关。本项目在明确YFT1遗传学功能和调控乙烯信号和合成基础上，解析了YFT1对番茄果实硬度形成相关基因表达、细胞显微结构、水解酶活性及初生壁和膨压相关化学组分累积影响，用RT-qPCR和RNA-seq分析了YFT1对番茄初生壁相关基因GAPTs (genes associated the primary cell wall of tomato fruit)转录调控，进一步揭示了GAPTs基因（SLCEL2、SLCESA2、SLEXP1和SLPL）互作对番茄果实硬度形成的影响和分子机制。该项目研究发表了相关学术论文8篇，国家发明专利授权2项；培养硕士生3名，博士生2名，博士后1名。深入地揭示了YFT1通过乙烯信号调控GAPTs表达并控制番茄果实硬度形成的遗传学机制，为番茄品质改良和育种提供了重要理论依据。