Wang Yun, Zhai Laiyuan, Chen Kai, Shen Congcong, Liang Yuntao, Wang Chunchao, Zhao Xiuqin, Wang Shu, Xu Jianlong
Rice Research Institute, Shenyang Agricultural University, Shenyang, 110866, Liaoning, China.
Institute of Crop Sciences/National Key Facility for Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
Rice (N Y). 2020 Feb 28;13(1):14. doi: 10.1186/s12284-020-00374-8.
The grain number per panicle (GNP), which is one of three grain yield components, is an important trait for the genetic improvement of rice. Although the NAL1 and GNP1 genes regulating the rice GNP and grain yield have been cloned, their allelic diversity, functional differences in rice germplasms, and effects of their combination on GNP and grain yield remain unclear.
Based on DNA sequences of these two genes in 198 cultivated rice (Oryza sativa) and 8-10 wild rice (Oryza rufipogon) germplasms, 16 and 14 haplotypes were identified for NAL1 and GNP1, respectively. The NAL1 gene had the strongest effects on GNP in indica (xian) and japonica (geng) subpopulations. In contrast, GNP1 had no significant effects in the geng subpopulation and was rare in the xian background, in which the superior GNP1 allele (GNP1-6) was detected in only 4.0% of the 198 germplasms. Compared with the transgenic lines with GNP1 or NAL1, the transgenic lines with both genes had a higher GNP (15.5%-25.4% and 11.6%-15.9% higher, respectively) and grain yield (5.7%-9.0% and 8.3%-12.3% higher, respectively) across 3 years. The two genes combined in the introgression lines in Lemont background resulted in especially favorable effects on the GNP.
Our results indicated that the GNP1 and NAL1 exhibited obvious differentiation and their combinations can significantly increase the grain yield in geng rice cultivars. These observations provide insights into the molecular basis of the GNP and may be useful for rice breeding of high yield potential by pyramiding GNP1 and NAL1.
每穗粒数（GNP）是水稻产量构成三要素之一，是水稻遗传改良的重要性状。尽管调控水稻GNP和产量的NAL1和GNP1基因已被克隆，但其等位基因多样性、在水稻种质中的功能差异以及它们的组合对GNP和产量的影响仍不清楚。
基于198份栽培稻（Oryza sativa）和8 - 10份野生稻（Oryza rufipogon）种质中这两个基因的DNA序列，分别鉴定出NAL1和GNP1的16种和14种单倍型。NAL1基因对籼稻和粳稻亚群的GNP影响最强。相比之下，GNP1在粳稻亚群中无显著影响，在籼稻背景中罕见，在198份种质中仅4.0%检测到优良的GNP1等位基因（GNP1 - 6）。与含有GNP1或NAL1的转基因系相比，同时含有这两个基因的转基因系在3年中GNP更高（分别高15.5% - 25.4%和11.6% - 15.9%），产量也更高（分别高5.7% - 9.0%和8.3% - 12.3%）。在Lemont背景的渗入系中，这两个基因的组合对GNP产生了特别有利的影响。
我们的结果表明，GNP1和NAL1表现出明显的分化，它们的组合可显著提高粳稻品种的产量。这些观察结果为GNP的分子基础提供了见解，可能有助于通过聚合GNP1和NAL1进行高产潜力水稻育种。
