SlHD31调控番茄单性结实的机理研究

Tomato is one of the most important vegetables worldwide. Adverse environmental factors and lack of pollinators, which affect fruit initiation, are major hindrances for year-round fertilization-dependent tomato yielding. Identification of parthenocarpic genes, creation of new germplasm resources and breeding of parthenocarpic cultivars are effective ways to solve this problem. In our previous study, a parthenocarpic gene encoding SlHD31 transcription factor was finely mapped based on F2 segregation population developed from a cross between a parthenocarpic line ‘90-16’ and a non-parthenocarpic cultivar ‘ZF-2’. Complementation assay and CRISPR/Cas9-based genome editing experiment confirmed the role of SlHD31 in regulation of parthenocarpy. Besides, SlHD31 was found to be highly expressed in unopened flower buds specifically. In this project, we will analyze the gene expression pattern, research downstream target genes and interacting proteins of SlHD31 as well as its relationship with phytohormones to elucidate the SlHD31-mediated transcriptional regulation network on parthenocarpy. The result will not only deepen our understandings of fruit set regulatory network, but also lay a solid theoretical foundation for the germplasm innovation and parthenocarpic cultivar generation.

番茄是世界范围内广泛种植的重要设施栽培蔬菜。传粉媒介的缺乏及不利的气象因素，会使番茄授粉受精不良，从而导致落花落果和产量下降。分离鉴定番茄中的单性结实基因，利用分子生物学手段创新种质和选育单性结实品种是解决上述问题的有效手段。我们以单性结实品系‘90-16’与非单性结实品种‘ZF-2’杂交产生的F2代分离群体为材料，通过图位克隆、遗传互补和基因组编辑实验成功鉴定到单性结实相关基因SlHD31，该基因编码含HD结构域的转录因子，且在未开放的花芽中特异性高表达。本项目拟在此基础上，综合运用细胞生物学、遗传学、生物化学和分子生物学等方法，研究SlHD31的表达模式、下游基因、互作蛋白及与激素信号间的关系，解析SlHD31调控番茄单性结实的分子机理，阐明SlHD31介导的转录调控网络。研究结果不仅可以完善果实发育的转录调控网络，而且可以为番茄单性结实种质创新和新品种选育奠定重要理论基础。

单性结实是重要的园艺性状。番茄是世界范围内广泛种植的重要设施栽培蔬菜，但单性结实种质资源相对缺乏。分离鉴定番茄中的单性结实基因，利用分子生物学手段创新种质和选育单性结实品种是解决上述问题的有效手段。我们以单性结实品系‘90-16’与非单性结实品种‘ZF-2’杂交产生的F2代分离群体为材料，通过图位克隆、遗传互补和基因组编辑实验成功鉴定到单性结实相关基因SlZHD17，该基因编码含HD结构域的转录因子，且在未开放的花芽中特异性高表达。进一步，我们通过酵母双杂交实验和烟草荧光素酶互补实验发现SlZHD17与SlZHD8、SlZHD11互作。通过RNA-Seq和ChIP-Seq，我们发现了一系列受SlZHD17直接调控的下游基因，其中包括赤霉素合成和代谢基因。本项目研究结果不仅可以完善SlZHD17介导的果实发育调控网络，而且可以为番茄单性结实种质创新和新品种选育奠定重要理论基础。