GhTUA2 promote roots elongation through regulating cell wall synthesis in cotton

This study investigates the molecular mechanisms regulating taproot elongation in cotton, focusing on the microtubule-associated gene GhTUA2. Transcriptomic analysis of two cotton phenotypes with contrasting root lengths identified a key gene module correlated with elongation, in which GhTUA2 emerged as a hub gene. Evolutionary analysis revealed structural conservation of tubulin family genes, particularly α- and β-tubulins, across diploid and tetraploid cotton species. Functional characterization demonstrated that overexpression of GhTUA2 significantly promotes taproot elongation at early seedling stages, primarily by upregulating genes involved in cell wall biosynthesis and secondary cell wall formation, and GhTUA2 also enhances lateral root formation and modulates pathways related to ion transport and stress adaptation, indicating a stage-specific shift in its regulatory role. These findings establish GhTUA2 as a regulator integrating microtubule dynamics, cell wall remodeling, and stress responses to optimize root architecture. The study provides novel genetic insights and potential targets for breeding cotton varieties with improved root systems and enhanced resilience to abiotic stresses.