Table2_Systematic Analysis of NB-ARC Gene Family in Rice and Functional Characterization of GNP12.xlsx

The NB-ARC (nucleotide-binding adaptor shared by APAF-1, R proteins, and CED-4) gene family plays a critical role in plant development. However, our understanding of the mechanisms of how NB-ARC genes regulate plant development in the plant panicle is still limited. Here, we subjected 258 NB-ARC genes in rice to genome-wide analysis to characterize their structure, function, and expression patterns. The NB-ARC genes were classified into three major groups, and group II included nine subgroups. Evolutionary analysis of NB-ARC genes in a dicotyledon plant (Arabidopsis thaliana) and two monocotyledonous plants (Oryza sativa L. and Triticum aestivum) indicated that homologous genome segments were conserved in monocotyledons and subjected to weak positive selective pressure during evolution. Dispersed and proximal replication events were detected. Expression analysis showed expression of most NB-ARC genes in roots, panicles, and leaves, and regulation at the panicle development stage in rice Ce253. The GNP12 gene encodes RGH1A protein, which regulates rice yield according to panicle length, grain number of panicle, and grain length, with eight major haplotypes. Most members of NB-ARC protein family are predicted to contain P-loop conserved domains and localize on the membrane. The results of this study will provide insight into the characteristics and evolution of NB-ARC family and suggest that GNP12 positively regulates panicle development.

NB-ARC（nucleotide-binding adaptor shared by APAF-1, R proteins, and CED-4，即APAF-1、R蛋白与CED-4共有的核苷酸结合适配子）基因家族在植物发育中发挥关键作用。然而，目前学界对于NB-ARC基因调控植物穗发育的分子机制仍了解有限。本研究对水稻中的258个NB-ARC基因开展全基因组分析，以解析其结构、功能及表达模式。研究将NB-ARC基因划分为3个主要类群，其中类II包含9个亚类。对双子叶植物拟南芥（Arabidopsis thaliana）以及2种单子叶植物水稻（Oryza sativa L.）和普通小麦（Triticum aestivum）中的NB-ARC基因进行进化分析，结果显示同源基因组区段在单子叶植物中保守存在，且进化过程中受到弱正选择压力。研究还检测到分散复制和近端复制事件。表达分析表明，大多数NB-ARC基因在根、穗和叶片中表达，并在水稻Ce253的穗发育阶段受到调控。GNP12基因编码RGH1A蛋白，该蛋白通过调控穗长、穗粒数和粒长影响水稻产量，共存在8种主要单倍型。预测显示，大多数NB-ARC蛋白家族成员含有P环保守结构域，且定位于细胞膜上。本研究结果将为NB-ARC基因家族的特征与进化研究提供新的见解，并表明GNP12对水稻穗发育具有正向调控作用。