Yang Tifeng, Dong Jingfang, Xiong Xijuan, Zhang Longting, Wang Jian, Hu Haifei, Zhou Lian, Yang Wu, Ma Yamei, Fu Hua, Chen Jiansong, Li Wenhui, Nie Shuai, Liu Ziqiang, Liu Bin, Wang Feng, Zhao Junliang, Zhang Shaohong
Rice Research Institute, Guangdong Key Laboratory of New Technology in Rice Breeding, Rice Engineering Laboratory, Key Laboratory of Genetics and Breeding of High Quality Rice in Southern China (Co-construction by Ministry and Province), Ministry of Agriculture and Rural Affairs, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, Guangdong, China.
College of Agriculture, South China Agricultural University, Guangzhou, 510642, China.
Rice (N Y). 2024 Aug 10;17(1):49. doi: 10.1186/s12284-024-00728-6.
Strong early growth vigor is an essential target in both direct seeded rice breeding and high-yielding rice breeding for rice varieties with relatively short growth duration in the double-cropping region. Shoot dry weight (SDW) is one of the important traits associated with early growth vigor, and breeders have been working to improve this trait. Finding stable QTLs or functional genes for SDW is crucial for improving the early growth vigor by implementing molecular breeding in rice. Here, a genome-wide association analysis revealed that the QTL for SDW, qSDW-5, was stably detected in the three cultivation methods commonly used in production practice. Through gene-based haplotype analysis of the annotated genes within the putative region of qSDW-5, and validated by gene expression and knockout transgenic experiments, LOC_Os05g09520, which is identical to the reported GW5/GSE5 controlling grain width (GW) and thousand grain weight (TGW) was identified as the causal gene for qSDW-5. Five main haplotypes of LOC_Os05g09520 were identified in the diverse international rice collection used in this study and their effects on SDW, GW and TGW were analyzed. Phenotypic comparisons of the major haplotypes of LOC_Os05g09520 in the three subpopulations (indica, japonica and aus) revealed the same patterns of wider GW and higher TGW along with higher SDW. Furtherly, the haplotype analysis of 138 rice varieties/lines widely used in southern China showed that 97.8% of the cultivars/lines carry Hap2. These results not only provide a promising gene source for the molecular breeding of rice varieties with strong early growth vigor, but also elucidate the effect of the LOC_Os05g09520 haplotypes on SDW, GW, and TGW in rice. Importantly, this study provides direct genetic evidence that these three traits are significantly correlated, and suggests a breeding strategy for developing high-yielding and slender grain-shaped indica cultivars with strong early growth vigor.
在双季稻种植区，对于生育期相对较短的水稻品种而言，较强的早期生长活力是直播稻育种和高产水稻育种的重要目标。地上部干重（SDW）是与早期生长活力相关的重要性状之一，育种工作者一直在努力改良这一性状。找到控制SDW的稳定数量性状位点（QTL）或功能基因对于通过水稻分子育种提高早期生长活力至关重要。在此，全基因组关联分析表明，在生产实践中常用的三种栽培方式下，均能稳定检测到控制SDW的QTL，即qSDW - 5。通过对qSDW - 5推定区域内注释基因进行基于基因的单倍型分析，并经基因表达和基因敲除转基因实验验证，确定与已报道的控制粒宽（GW）和千粒重（TGW）的GW5/GSE5相同的LOC_Os05g09520基因是qSDW - 5的因果基因。在本研究中使用的不同国际水稻种质资源中鉴定出LOC_Os05g09520的五种主要单倍型，并分析了它们对SDW、GW和TGW的影响。对三个亚群（籼稻、粳稻和aus稻）中LOC_Os05g09520主要单倍型的表型比较显示，GW变宽、TGW增加以及SDW提高的模式相同。此外，对中国南方广泛使用的138个水稻品种/品系进行单倍型分析表明，97.8%的品种/品系携带单倍型2。这些结果不仅为具有较强早期生长活力的水稻品种分子育种提供了有前景的基因资源，还阐明了LOC_Os05g09520单倍型对水稻SDW、GW和TGW的影响。重要的是，本研究提供了直接的遗传证据，证明这三个性状显著相关，并提出了一种培育具有较强早期生长活力、高产且粒形细长的籼稻品种的育种策略。
