瓠瓜OVATE家族基因挖掘鉴定及与果形发育的关系研究

Bottle gourd is one of the most important cucurbit vegetables in China. There is tremendous genetic diversity in fruit shapes in the bottle gourd germplasm, yet the mechanism underlying this trait remains unknown. In previous studies, we performed RAD-Seq genotyping on a natural population comprising 80 accessions, based on which two sub-gene pools were suggested for association with fruit shape. Outlier test suggested a locus on LG7 to be a candidate site under selection, which harbors an ortholog of the tomato fruit shape gene OVATE. This OVATE ortholog is temporally referred to as LsOVATE1. In this study we will focus on the characterization and analyses of genetic variation and expression patterns of OVATE gene family member in the bottle gourd. The similarities and differences of OVATE gene family member in the bottle gourd will be compared with that of tomato to elucidate the conservatism/diversity of this kind of gene family in different crops. Natural variations of OVATE gene family will be investigated to reveal the association of sequence variation and fruit shape, and further identify OVATE homologous genes with special interest that are associated with fruit shape. In addition, the biological function of LsOVATE1 and other OVATE homologous genes with special interest will be investigated by pollen magnetic transfection-based transformation and CRISPR technologies, which will greatly deepen our understanding on the role of OVATE genes in fruit development in plants.

瓠瓜为我国重要传统特色瓜类蔬菜，果实形态各异，但调控机制未明。本项目组前期将80份瓠瓜自然种质资源划分为近圆和长直两大基本果形类群，通过群体遗传学分析和异常值检测，在第7染色体（LG7）上检测到一个瓠瓜果形候选位点，与番茄OVATE同源，命名为LsOVATE1。本项目拟以该基因及其家族成员为研究对象，通过生物信息学分析瓠瓜OVATE同源基因家族的特性特征、遗传变异和表达模式，比较与番茄OVATE基因家族的异同，阐明该类基因在不同科属植物间的保守性/多样性；通过关联分析揭示瓠瓜OVATE同源基因序列变异与瓠瓜果形的关系，鉴定与果形强烈关联的OVATE同源基因，并比较其序列变异或调控模式与番茄果形基因OVATE的异同；最后利用花粉磁转染和CRISPR技术明确LsOVATE1和鉴定出的其它果形关联OVATE同源基因在调控瓠瓜果形发育方面的作用，丰富对植物OVATE基因在果实发育过程中作用的认识。

瓠瓜为我国重要的传统特色瓜类蔬菜，果实形态各异，但调控机制未明。本项目通过生物信息学手段分析了瓠瓜中20个番茄OVATE同源基因家族的特性特征、遗传变异和表达模式，发现该类基因在不同科属植物间具有较高的保守性。通过不同果形材料不同时期子房转录组分析，构建了OVATE基因家族各成员在瓠瓜不同果形不同发育阶段子房中的表达谱；同时构建并分析了果形相关基因共表达网络，揭示了不同瓠瓜之间子房/果实形状差异的机制；针对20个OVATE同源基因在240份瓠瓜不同果形材料序列中的差异，结合果形表型进行全基因组关联分析，鉴定到与瓠瓜果形强烈关联的OVATE同源基因BG_GLEAN_10007209，也就是我们前期工作中鉴定 LsOVATE1 基因，异源转化蔬菜模式作物番茄后，果实异常，此外，还存在花萼肥厚、花瓣退化、花瓣花后不落等表型，初步验证了其在调控果实发育方面的功能，丰富了对植物OVATE基因在果实发育过程中作用的认知。