Background

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.

Results

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.

Conclusions

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.

中文翻译：

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GNP1和NAL1的自然序列变异和组合决定了水稻每穗粒数

背景

每穗粒数（GNP）是三个谷类产量构成要素之一，是水稻遗传改良的重要特征。尽管已经克隆了调节水稻GNP和谷粒产量的NAL1和GNP1基因，但它们的等位基因多样性，水稻种质的功能差异以及它们的组合对GNP和谷粒产量的影响仍不清楚。

结果

基于在198栽培稻（这两个基因的DNA序列稻）和8-10野生稻（普通野生稻）种质，16点14的单倍型进行鉴定为NAL1和GNP1分别。该NAL1基因在国民生产总值上最强的影响籼稻（西安）和粳稻（耿）亚群。相比之下，GNP1在耿氏亚群中没有显着影响，在西安背景中很少见，在该背景中，上等GNP1等位基因（GNP1–6）仅在198个种质中检测到4.0％。与具有GNP1或NAL1的转基因品系相比，具有两种基因的转基因品系均具有更高的GNP（分别高出15.5％–25.4％和11.6％–15.9％）和谷物产量（5.7％–9.0％和8.3％–12.3）。三年）。在Lemont背景下，基因渗入系中结合的两个基因对GNP产生了特别有利的影响。

结论

我们的结果表明，GNP1和NAL1表现出明显的分化，并且它们的组合可以显着提高耿稻品种的籽粒产量。这些发现为GNP的分子基础提供了见识，并可能通过将GNP1和NAL1金字塔化而对水稻高产潜力的育种有用。