Reduced RG-II pectin dimerization disrupts differential growth by attenuating hormonal regulation

作者：Pawan Kumar Jewaria, Bibek Aryal, Rifat Ara Begum, Yaowei Wang, Gloria Sáncho-Andrés, Abu Imran Baba, Meng Yu, Xiaojuan Li, Jinxing Lin, Stephen C. Fry, Stéphane Verger, Eugenia Russinova, Kristoffer Jonsson, Rishikesh P. Bhalerao · 发表于：Science Advances · 年份：2025 · DOI：10.1126/sciadv.ads0760 · 被引用次数：6 · 研究领域：Plant Molecular Biology Research、Polysaccharides and Plant Cell Walls、Plant Reproductive Biology

Defects in cell wall integrity (CWI) profoundly affect plant growth, although, underlying mechanisms are not well understood. We show that in Arabidopsis mur1 mutant, CWI defects from compromising dimerization of RG-II pectin, a key component of cell wall, attenuate the expression of auxin response factors ARF7-ARF19 . As a result, polar auxin transport components are misexpressed, disrupting auxin response asymmetry, leading to defective apical hook development. Accordingly, mur1 hook defects are suppressed by enhancing ARF7 expression. In addition, expression of brassinosteroid biosynthesis genes is down-regulated in mur1 mutant, and supplementing brassinosteroid or enhancing brassinosteroid signaling suppresses mur1 hook defects. Intriguingly, brassinosteroid enhances RG-II dimerization, showing hormonal feedback to the cell wall. Our results thus reveal a previously unrecognized link between cell wall defects from reduced RG-II dimerization and growth regulation mediated via modulation of auxin-brassinosteroid pathways in early seedling development.