Carbon-concentrating mechanisms in pods are key elements for terminal drought resistance in Phaseolus vulgaris.

This article focuses on the physiological and molecular mechanisms underlying terminal drought resistance in common bean (Phaseolus vulgaris L.), a staple legume crop vulnerable to yield losses exceeding 80% under drought during reproductive stages. Using two Durango race cultivars with contrasting drought tolerance—Pinto Saltillo (resistant) and Bayo Madero (sensitive)—the study combined transcriptomic analyses of source leaves, pod walls, and seeds with physiological measurements at the mid-pod-filling stage. Results indicate that the resistant cultivar enhances carbon recycling via photosynthesis, photorespiration, and CO2-concentrating mechanisms in pod walls, alongside increased sink strength and respiration-related gene expression in seeds, supporting efficient carbon translocation and biomass accumulation under drought. These findings highlight coordinated metabolic adjustments in pod walls and seeds as key contributors to terminal drought resistance in common bean.