Heat-drought stress reshapes carbon allocation in Pinus massoniana through a trehalose-linked lncRNA regulatory module

Heat and drought frequently co-occur under climate change and impose strong constraints on carbon allocation in forest tree species. Here, we investigated how trehalose-associated regulation integrates carbon metabolism and RNA-level control to enhance Pinus massoniana resilience to combined heat-drought stress. Trehalose-linked responses alleviated needle dehydration and stabilized carbon partitioning, characterized by increased sucrose accumulation, accelerated starch degradation, and reduced glucose levels under stress. These metabolic adjustments were accompanied by enhanced antioxidant capacity and lower oxidative damage. Integrated transcriptomic and proteomic analyses identified starch and sucrose metabolism as the most responsive pathway, with PmSUS4 and PmBGLU22 acting as central metabolic nodes. We further discovered that the lncRNA MSTRG.41543 interacts with PmBGLU22 , and validated its repressive activity using dual-luciferase and RNA pull-down assays, suggesting a feedback mechanism that fine-tunes carbon turnover during stress. Heterologous overexpression of PmSUS4 and PmBGLU22 in Arabidopsis thaliana confirmed their conserved roles in promoting sugar accumulation, enhancing antioxidant activity, and improving heat-drought tolerance. Together, our results demonstrate that trehalose-associated carbon metabolic reprogramming, coordinated by an lncRNA-mRNA regulatory module, plays a critical role in enhancing heat-drought resilience in P. massoniana . This study provides mechanistic insight into carbon allocation strategies of industrial forest tree species under climate extremes and offers potential targets for improving stress resilience and carbon productivity in plantation forestry. • Trehalose improves heat-drought tolerance by remodeling carbon allocation in Pinus massoniana . • An lncRNA-mediated module links trehalose signaling with carbon metabolism. • lncRNA MSTRG.41543 regulates PmSUS4 and PmBGLU22 to coordinate carbon metabolism and stress tolerance.