Table_4_Fine mapping and candidate gene analysis of gynoecy trait in chieh-qua (Benincasa hispida Cogn. var. chieh-qua How).xls

Gynoecy demonstrates an earlier production of hybrids and a higher yield and improves the efficiency of hybrid seed production. Therefore, the utilization of gynoecy is beneficial for the genetic breeding of chieh-qua. However, little knowledge of gynoecious-related genes in chieh-qua has been reported until now. Here, we used an F2 population from the cross between the gynoecious line ‘A36’ and the monoecious line ‘SX’ for genetic mapping and revealed that chieh-qua gynoecy was regulated by a single recessive gene. We fine-mapped it into a 530-kb region flanked by the markers Indel-3 and KASP145 on Chr.8, which harbors eight candidate genes. One of the candidate genes, Bhi08G000345, encoding networked protein 4 (CqNET4), contained a non-synonymous SNP resulting in the amino acid substitution of isoleucine (ATA; I) to methionine (ATG; M). CqNET4 was prominently expressed in the female flower, and only three genes related to ethylene synthesis were significantly expressed between ‘A36’ and ‘SX.’ The results presented here provide support for the CqNET4 as the most likely candidate gene for chieh-qua gynoecy, which differed from the reported gynoecious genes.

雌花现象在杂交品种的早期产生中表现出更高的产量，并提升了杂交种子的生产效率。因此，雌花的利用对于茄子的遗传育种具有重要意义。然而，关于茄子雌花相关基因的知识至今仍甚少。在本研究中，我们采用了‘A36’雌花系与‘SX’单性系杂交的F2群体进行基因定位分析，揭示了茄子雌花受单个隐性基因调控。我们将该基因精细定位至位于第8染色体上，被标记Indel-3和KASP145所夹持的530-kb区域内，该区域内含有八个候选基因。其中，一个候选基因Bhi08G000345编码网络蛋白4（CqNET4），含有一个非同义单核苷酸多态性（SNP），导致异亮氨酸（ATA；I）被蛋氨酸（ATG；M）所取代。CqNET4在雌花中显著表达，而在‘A36’与‘SX’之间，仅有三个与乙烯合成相关的基因表达显著。本研究结果为CqNET4作为茄子雌花最可能的候选基因提供了支持，这与已报道的雌花基因存在差异。