茄子与其野生近缘种有性杂交生殖差异及种质创新研究

Eggplant (Solanum melongena L.)possesses a very important part among vegetable productions. At present, solanumspecies in the world havereached thousands of types. Wild resources of most related species contain many merits that are scarce in cultivated eggplant varieties. Thus, distant hybridization of cultivated varieties and wild varieties would be an effective way to improve solanum resistance. Previous reports showed various productive disorders existedamong distant related species, andembryo abortion after the hybridization was a most common phenomenon. However, the mechanism of embryo abortion remains unknown,whichhas aserious influence on thebreeding effects and application of solanum wild resources.We have carried out the works of collection, identification, conservation and interspecific hybridization on wild resources of most related eggplant species and found that cross-compatibilities mainly depended on the distance of genetic relationship, and interspecific hybridization of closer relationship was conducive to the normal development of embryo and later generations inSolanum.Based on the previous studies on identification of materials and distant hybridization, we plan to identifyembryo abortionrelated genes throughproteomics and molecular biology technologies using wild eggplant varieties and semi-wild cultivated varieties collected from home and abroad. This study wouldhelp for deciphering the mechanism of embryo abortion at molecular level, and provide theoretical basis for overcoming embryo abortion and conducting solanum germplasm innovation. Therefore, this studyprovides high scientific significance and important application value.

茄子缺少茄属野生资源中许多优良抗性基因，进行远缘杂交是改良茄子抗性的有效途径。研究表明，茄属远缘杂交存在生殖障碍，其中杂交后胚胎大量败育是最为常见的现象，但迄今为止有关胚胎败育的机理仍不清楚，严重地影响茄属野生近缘种的利用和育种效果。课题组前期开展了茄属野生近缘种资源收集、鉴定、保存和种间杂交等研究工作，发现茄属种间杂交亲和性主要取决于两者的亲缘关系，亲缘关系较近的种间杂交有利于胚胎发育和后代正常繁育。基于前期材料鉴定和远缘杂交研究工作基础，本研究从国内外收集的茄属野生种与半野生栽培茄为研究对象，开展茄属种质资源亲缘关系的划分和种间杂交，并依据种间杂交可育/败育的差异，再通过蛋白质组学和转录组学等技术挖掘调控胚胎败育的相关基因，旨在从分子水平上阐明茄属远缘杂交中胚胎败育的原因，为采取有效措施克服胚胎败育以及进行茄属种质创新提供理论依据。因此，本项研究具有较高的科学意义和应用价值。

茄属野生种保留了许多优良性状，栽培茄与野生种进行杂交，是茄子品种改良与创新的重要方法。本研究收集和引进茄属种质资源1540份，通过表型鉴定结合SSR、SRAP标记和GBS技术，茄属种质资源划分为野生种、野生近缘种、初级栽培种和高级栽培种，揭示了不同茄子种群之间遗传距离与杂交亲和性，并按照其与栽培种杂交难易程度划分为难、偏难、较易、易4个类型。开展以茄子（177、SHF）和红茄（53、Y11）、水茄（ST）为材料，栽培茄作为母本、水茄和红茄作为父本杂交，自交作为对照，通过花粉粒形态观察、花粉活力检测、授粉组合春秋两季座果率比较、单果种数统计来分析杂交亲和性，研究表明栽培种和野生种杂交受精前未发现生殖障碍，但自交单果种子数显著多于杂交组合，并且栽培茄与水茄杂交种子千粒重显著低于自交种。开展种间杂交授粉受精过程差异机制研究，177 0天、177 4天、177 6天、177×53 4天、177×53 6天、177×Y11 4天、177×Y11 6天的子房进行转录组测序，进行KEGG富集发现 DEGs 主要富集在植物信号转导、植物病原体互作、泛素介导的蛋白水解、MAPK信号转导等途径，这些途径可能参与了双受精过程，通过用 q-PCR 对12个候选基因进行表达模式分析与RNA-Seq结果基本一致。开展受精后胚乳发育差异研究，试验材料177自交、177×ST、SHF自交、SHF×ST及ST自交授粉后45天的胚乳进行转录组测序，在SHF×ST中共鉴定到268个等位基因，其中232个为母本等位基因，34个为父本等位基因；在177×ST中共鉴定到41个等位基因，其中33个为母本等位基因，共鉴定到8个为父本等位基因。经FDR＜0.05矫正，最终在远缘杂交种胚乳中筛选到四个印迹基因，包括2个母本印迹基因EGP09668、EGP31530；2个父本印迹基因EGP30614、EGP31283。