Table_9_Use of Transcriptomic Analyses to Elucidate the Mechanism Governing Nodal Root Development in Eremochloa ophiuroides (Munro) Hack..xlsx

Centipedegrass [Eremochloa ophiuroides (Munro) Hack.] is a perennial warm-season grass that originated in China, and its speed of nodal rooting is important for lawn establishment. In our study, centipedegrass nodal rooting ability was limited by node aging. Transcriptome sequencing of nodal roots after 0, 2, 4, and 8 days of water culture was performed to investigate the molecular mechanisms of root development. GO enrichment and KEGG pathway analyses of DEGs indicated that plant hormone signal transduction and transcription factors might play important roles in centipedegrass nodal root growth. Among them, E3 ubiquitin-protein ligases participated in multiple hormone signal transduction pathways and interacted with transcription factors. Furthermore, an E3 ubiquitin protein ligase EoSINAT5 overexpressed in rice resulted in longer roots and more numerous root tips, while knockout of LOC_Os07g46560 (the homologous gene of EoSINAT5 in rice) resulted in shorter roots and fewer root tips. These results indicated that EoSINAT5 and its homologous gene are able to promote nodal root development. This research presents the transcriptomic analyses of centipedegrass nodal roots, and may contribute to elucidating the mechanism governing the development of nodal roots and facilitates the use of molecular breeding in improving rooting ability.

假俭草（Eremochloa ophiuroides (Munro) Hack.）为原产于中国的多年生暖季型草本植物，其节根生根速率对草坪建植至关重要。本研究发现，假俭草的节根生根能力受节点衰老的限制。为解析其根系发育的分子机制，本研究对水培0、2、4、8天后的节根样本开展了转录组测序。通过对差异表达基因（Differentially Expressed Genes, DEGs）进行基因本体（Gene Ontology, GO）富集分析与京都基因与基因组百科全书（Kyoto Encyclopedia of Genes and Genomes, KEGG）通路富集分析，结果显示植物激素信号转导与转录因子可能在假俭草节根生长过程中发挥关键调控作用。其中，E3泛素蛋白连接酶（E3 ubiquitin-protein ligases）参与了多条激素信号转导通路，并可与转录因子产生相互作用。进一步功能验证实验表明，在水稻中过表达E3泛素蛋白连接酶EoSINAT5可使植株根系更长、根尖数量更多；而敲除水稻中EoSINAT5的同源基因LOC_Os07g46560后，植株根系则更短、根尖数量更少。上述实验结果证实，EoSINAT5及其同源基因能够促进节根发育。本研究完成了假俭草节根的转录组分析，可为阐明节根发育的调控机制提供数据支撑，并有助于推动分子育种技术在提升生根能力的育种实践中的应用。