Sun Zhiguang, An Hongzhou, Qiu Zeyu, Li Jingfang, Li Jian, Yang Bo, Liu Jinbo, Chen Tingmu, Zhang Yuqin, Lu Baiguan, Liu Yan, Wang Baoxiang, Xu Dayong
Institute of Rice Research, Lianyungang Academy of Agricultural Sciences, Lianyungang, China.
The Key Laboratory of Crop Genetics and Breeding of Hebei Province, Institute of Cereal and Oil Crops, Hebei Academy of Agriculture and Forestry Sciences, Shijiazhuang, China.
Front Plant Sci. 2025 Mar 31;16:1579589. doi: 10.3389/fpls.2025.1579589. eCollection 2025.
Grain volume is a key agronomic trait of rice. It is coordinately determined by grain length, width, thickness, and roundness, which influences the rice yield and quality, yet the molecular mechanism is still not fully understood.
In this study, a mapping population of Ludao (weedy rice) and Guangbaixiangzhan (GBXZ) was developed in Lianyungang, Jiangsu province, China, and was employed to construct a high-density genetic map by use of the RICE 1 K mGPS chip in 2021. The mapping of QTLs was carried out with IciMapping software using the inclusive composite interval mapping (ICIM) method.
A total of eight QTLs for grain volume, explained 4.22-19.75% of the total phenotypic variation, were detected with LOD scores ranging from 3.33 to 13.25. Among these loci, five are known genes or loci related to grain size, and three loci, , , and , were newly identified. The major QTL, , explained the highest phenotypic variation, was validated using NIL pairs. By combining gene functional annotation, gene expression analysis and sequence comparison within the mapping interval of , a candidate gene (), encoding an ethylene receptor, OsETR4, was identified. Further haplotype-phenotype analysis revealed this gene to be significantly associated with grain length, width, and thousand-grain weight. Thus we identified as the most likely candidate gene. Taken together, our findings provide a basis for functional research on , and broaden our understanding of role of genetic factors in regulating grain volume, thus providing an important resource for yield improvement in rice.
粒体积是水稻的一个关键农艺性状。它由粒长、粒宽、粒厚和粒形共同决定，影响水稻产量和品质，但其分子机制仍未完全清楚。
本研究在江苏省连云港市构建了鲁稻（杂草稻）和广白香占（GBXZ）的作图群体，并于2021年利用RICE 1K mGPS芯片构建了高密度遗传图谱。利用完备复合区间作图（ICIM）方法，使用IciMapping软件进行QTL定位。
共检测到8个控制粒体积的QTL，解释了4.22%-19.75%的表型变异，LOD值范围为3.33至13.25。在这些位点中，5个是已知的与粒大小相关的基因或位点，3个位点，即、和，是新鉴定的。主效QTL解释了最高的表型变异，通过近等基因系对进行了验证。通过结合基因功能注释、基因表达分析和在的定位区间内的序列比较，鉴定出一个候选基因（），其编码乙烯受体OsETR4。进一步的单倍型-表型分析表明该基因与粒长、粒宽和千粒重显著相关。因此，我们确定为最有可能的候选基因。总之，我们的研究结果为的功能研究提供了基础，并拓宽了我们对遗传因素在调节粒体积中作用的理解，从而为水稻产量提高提供了重要资源。
