Multidimensional Strategies for Enhancing Heat Stress Tolerance in Pulses: From Trait Dissection to Genomic Innovation

Abstract

Heat stress (HS) poses a critical constraint to the productivity and reproductive efficiency of pulse crops, particularly in arid and semi-arid agroecologies under projected climate change scenarios. Abiotic stresses are a leading cause of global crop losses, reducing the yield of many plants by over 50%. These stresses trigger a range of morphological, physiological, biochemical, and molecular changes that adversely affect plant growth, productivity, and yield. This review delineates the multifaceted plant responses to elevated temperatures, encompassing morphological adaptations, physiological adjustments (e.g., canopy temperature depression, membrane thermostability, and photosynthetic efficiency), and biochemical modifications such as reactive oxygen species (ROS) scavenging, osmolyte accumulation, and altered hormonal interactions. Recent advances in molecular genetics show that certain proteins and molecules—like transcription factors (such as DREB, HSFs, and NACs), heat shock proteins (HSPs), and small RNAs—work together to control how plants respond and adapt to heat stress. The deployment of high-throughput omics approaches—transcriptomics, proteomics, and metabolomics—has facilitated the identification of key stress-responsive genes, pathways, and candidate quantitative trait loci (QTLs). Integration of these insights into breeding pipelines through marker-assisted selection, genomic selection, and genome editing (CRISPR/Cas9) offers promising avenues for accelerating the development of heat-resilient pulse genotypes. The review underscores the imperative of systems-level approaches to dissect the genetic architecture of heat stress tolerance and to enhance climate resilience in pulse crop improvement programs. The use of 'omics' technologies, including genomics, transcriptomics, proteomics, and metabolomics, is crucial for understanding the molecular basis and processes involved in plant responses to heat stress and the mechanisms of tolerance.