Zhu Yaoyao, Ye Jiang, Zhan Jiepeng, Zheng Xiaoxiao, Zhang Jiangjiang, Shi Jiaqin, Wang Xinfa, Liu Guihua, Wang Hanzhong
Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministryof Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan, China.
Front Plant Sci. 2020 Feb 21;11:68. doi: 10.3389/fpls.2020.00068. eCollection 2020.
Seed number is a key character/trait tightly related to the plant fitness/evolution and crop domestication/improvement. The seed number per silique (SNPS) shows a huge variation from several to more than 30, however the underlying regulatory mechanisms are poorly known, which has hindered its improvement. To answer this question, several representative lines with extreme SNPS were previously subjected to systematic genetic and cytological analyses. The results showed that the natural variation of seed number per silique is mainly controlled by maternal and embryonic genotype, which are co-determined by ovule number per ovary, fertile ovule ratio, ovule fertilization rate, and fertilized ovule development rate. More importantly, we also mapped two repeatable quantitative trait loci (QTLs) for SNPS using the F population derived from Zhongshuang11 and No. 73290, of which the major QTL has been fine-mapped. In the current study, the near-isogenic lines (NILs) of were successfully developed by the successive backcross of F with Zhongshuang11. First, the effect of was validated by evaluating the SNPS of two types of homozygous NILs from BCF population, which showed a significant difference of 2.23 on average. Then, was successfully fine-mapped from the original 4.237 to 1.389 Mb, using a BCF segregating population of 2,551 individuals. To further clarify the regulatory mechanism of , the two types of homologous NILs were subjected to genetic and cytological analyses. The results showed that the difference in SNPS between the two homologous NILs was determined by the embryonic genotypic effect. Highly accordant with this, no significant difference was observed in ovule number per ovary, ovule fertility, fertilization rate, and pollen fertility between the two homologous NILs. Therefore, the regulatory mechanism of is completely different from the cloned and . These results will advance the understanding of SNPS and facilitate gene cloning and molecular breeding in .
种子数量是与植物适应性/进化以及作物驯化/改良密切相关的关键性状。每角果种子数（SNPS）表现出从几个到30多个的巨大变异，然而其潜在的调控机制却知之甚少，这阻碍了对其进行改良。为回答这个问题，先前对几个具有极端SNPS的代表性品系进行了系统的遗传和细胞学分析。结果表明，每角果种子数的自然变异主要由母体和胚胎基因型控制，这由每个子房的胚珠数、可育胚珠比率、胚珠受精率和受精胚珠发育率共同决定。更重要的是，我们还利用来自中双11号和73290号的F群体定位了两个可重复的SNPS数量性状位点（QTL），其中主要QTL已被精细定位。在本研究中，通过F与中双11号的连续回交成功培育出了近等基因系（NILs）。首先，通过评估来自BCF群体的两种纯合NILs的SNPS验证了的效应，平均差异为2.23。然后，利用2551个个体的BCF分离群体将成功从最初位置精细定位到1.389 Mb，范围从4.237 Mb缩小。为进一步阐明的调控机制，对两种同源NILs进行了遗传和细胞学分析。结果表明，两种同源NILs之间SNPS的差异由胚胎基因型效应决定。与此高度一致的是，两种同源NILs之间在每个子房的胚珠数、胚珠育性、受精率和花粉育性方面未观察到显著差异。因此，的调控机制与已克隆的和完全不同。这些结果将推进对SNPS的理解，并促进中的基因克隆和分子育种。
