Oaks drought-induced responses under root types: gene and microRNA cooperation

Drought is a major stressor limiting plant growth and survival, requiring adaptive strategies. This study reveals that oak seedlings deploy distinct molecular and hormonal responses to drought depending on root type and cultivation method (containerized vs acorn-sown seedlings). Taproots and lateral roots exhibited divergent responses: taproots prioritized metabolic adaptation and sustained growth, while lateral roots emphasized growth restriction and structural adjustment. Seedlings initially grown in containers displayed unique transcriptomic and miRNA profiles compared to acorn-sown controls, reflecting the legacy of early root system constraints. Key regulatory networks involving stress-responsive genes, miRNAs, and hormones (notably ABA, JA, SA, and reduced auxins and cytokinins) underpin these adaptations. Our findings underscore the critical role of diversity within root types and cultivation techniques in enhancing drought resilience in oaks, and reveal often-overlooked molecular mechanisms that are vital to effective reforestation strategies aimed at climate mitigation and ecosystem restoration.