Key Laboratory of Forage and Endemic Crop Biology, Ministry of Education, School of Life Sciences, Inner Mongolia University, Hohhot, 010010, China.
Grassland Work Station of East Ujimqin Banner of Xilin Gol League of Inner Mongolia, East Ujimqin Banner, 026300, China.
J Plant Physiol. 2023 Aug;287:154003. doi: 10.1016/j.jplph.2023.154003. Epub 2023 May 19.
Leymus chinensis, a perennial native forage grass, is widely distributed in the steppes of Inner Mongolia as the dominant species. The main reproductive strategy of this grass is clonal propagation, which occurs via the proliferation of subterranean horizontal stems known as rhizomes. To elucidate the mechanism underlying rhizome development in this grass, we collected 60 accessions of L. chinensis and evaluated their rhizome development. One accession, which we named SR-74 (Strong Rhizomes), had significantly better rhizome development capacity than the accession WR-16 (Weak Rhizomes) in terms of rhizome number, total and primary rhizome length, and number of rhizome seedlings. Rhizome elongation was positively correlated with the number of internodes in the rhizome, which affected plant biomass. Compared to WR-16, SR-74 had higher rhizome tip hardness, higher abundance of transcripts participating in the biosynthesis of cell wall components, and higher levels of the metabolites L-phenylalanine, trans-cinnamic acid, 3-coumaric acid, ferulic acid, and coniferin. These metabolites in the phenylpropanoid biosynthesis pathway are precursors of lignin. In addition, SR-74 rhizomes contained higher amounts of auxin and auxin metabolites, including L-Trp, IPA, IBA, IAA and IAA-Asp, as well as upregulated expression of the auxin biosynthesis and signaling genes YUCCA6, YUCCA8, YUCCA10, YUCCA11, PIN1, PIN2, UGT1, UGT2, UGT4, UGT10, GH3, IAA7, IAA23, and IAA30. We propose a network between auxin signaling and the cell wall underlying rhizome development in L. chinensis.
赖草是一种广泛分布于内蒙古草原的多年生乡土牧草，作为优势种。这种草的主要繁殖策略是克隆繁殖，通过地下水平茎的增殖来实现，这些茎被称为根茎。为了阐明这种草根茎发育的机制，我们收集了 60 份赖草的样本，并评估了它们的根茎发育情况。一个名为 SR-74（强根茎）的样本与 WR-16（弱根茎）相比，具有更强的根茎发育能力，表现在根茎数量、总根茎和主根茎长度以及根茎苗数量方面。根茎伸长与根茎节间数量呈正相关，而节间数量又影响植物生物量。与 WR-16 相比，SR-74 的根茎顶端硬度更高，参与细胞壁成分生物合成的转录本丰度更高，以及 L-苯丙氨酸、反式肉桂酸、3-咖啡酸、阿魏酸和松柏醇等代谢物水平更高。苯丙烷生物合成途径中的这些代谢物是木质素的前体。此外，SR-74 的根茎含有更多的生长素和生长素代谢物，包括 L-Trp、IPA、IBA、IAA 和 IAA-Asp，以及生长素生物合成和信号转导基因 YUCCA6、YUCCA8、YUCCA10、YUCCA11、PIN1、PIN2、UGT1、UGT2、UGT4、UGT10、GH3、IAA7、IAA23 和 IAA30 的上调表达。我们提出了一个在赖草根茎发育中涉及生长素信号转导和细胞壁的网络。
