Department of Biochemistry & Biophysics, Texas A&M University, College Station, Texas, 77843, USA.
Department of Plant Biology, Michigan State University, East Lansing, Michigan, 48824, USA.
Plant J. 2021 Feb;105(4):1053-1071. doi: 10.1111/tpj.15086. Epub 2020 Dec 12.
Stems of bioenergy sorghum (Sorghum bicolor L. Moench.), a drought-tolerant C4 grass, contain up to 50 nodes and internodes of varying length that span 4-5 m and account for approximately 84% of harvested biomass. Stem internode growth impacts plant height and biomass accumulation and is regulated by brassinosteroid signaling, auxin transport, and gibberellin biosynthesis. In addition, an AGCVIII kinase (Dw2) regulates sorghum stem internode growth, but the underlying mechanism and signaling network are unknown. Here we provide evidence that mutation of Dw2 reduces cell proliferation in internode intercalary meristems, inhibits endocytosis, and alters the distribution of heteroxylan and mixed linkage glucan in cell walls. Phosphoproteomic analysis showed that Dw2 signaling influences the phosphorylation of proteins involved in lipid signaling (PLDδ), endomembrane trafficking, hormone, light, and receptor signaling, and photosynthesis. Together, our results show that Dw2 modulates endomembrane function and cell division during sorghum internode growth, providing insight into the regulation of monocot stem development.
生物能源高粱（Sorghum bicolor L. Moench.）的茎干，作为一种耐旱的 C4 草本植物，包含多达 50 个节点和不同长度的节间，跨度为 4-5 米，占收获生物质的大约 84%。茎节间的生长影响植物的高度和生物量积累，由油菜素内酯信号、生长素运输和赤霉素生物合成调节。此外，AGCVIII 激酶（Dw2）调节高粱茎节间的生长，但潜在的机制和信号网络尚不清楚。在这里，我们提供的证据表明 Dw2 突变减少了节间居间分生组织的细胞增殖，抑制了内吞作用，并改变了细胞壁中杂木聚糖和混合键葡聚糖的分布。磷酸蛋白质组学分析表明， Dw2 信号影响参与脂类信号（PLDδ）、内膜运输、激素、光照和受体信号以及光合作用的蛋白质的磷酸化。总之，我们的结果表明 Dw2 调节高粱节间生长过程中的内膜功能和细胞分裂，为单子叶植物茎发育的调控提供了新视角。
