Drought Tolerance Mechanisms in Sorghum Genotypes

Sorghum bicolor exhibits an array of adaptations to thrive under water‐limited conditions. At the morphological level, tolerant genotypes often display an enhanced root‐to‐shoot ratio, deeper rooting profiles and reduced leaf area to minimise water loss. Physiologically, stomatal conductance is tightly regulated to optimise water‐use efficiency (WUE), while osmotic adjustment through the accumulation of compatible solutes such as proline and glycine betaine maintains cell turgor. Biochemically, drought‐tolerant lines exhibit robust antioxidant systems—upregulated catalases, peroxidases and superoxide dismutases—to scavenge reactive oxygen species (ROS) generated under stress. Advances in proteomics and transcriptomics have identified candidate genes regulating these processes, including transcription factors from AP2/ERF, MYB and NAC families, as well as enzymes involved in hormone signalling (notably abscisic acid). Integration of quantitative trait locus (QTL) mapping and genome‐wide association studies (GWAS) has further pinpointed genomic regions controlling stay‐green phenotypes, root architecture and restricted transpiration. Together, these multifaceted mechanisms underpin sorghum’s resilience, offering a blueprint for breeding and biotechnological interventions aimed at sustaining grain yield and nutritional quality in drought‐prone regions.

Research from Nature Portfolio

Comparative physiological and proteome analyses in two genotypes with contrasting drought tolerance have revealed key networks underpinning water‐stress adaptation. The drought‐tolerant line rapidly closes stomata to conserve water and exhibits increased biosynthesis of glycine betaine in roots, boosting water uptake via enhanced osmotic potential. Concurrent accumulation of proline and maintenance of chlorophyll content protect photosynthetic capacity. A detailed root proteomic profile uncovered distinct clusters of proteins—such as aquaporins and antioxidant enzymes—whose abundance correlates with stress recovery post‐re‐watering, a trait absent in the sensitive genotype. These insights highlight rapid signalling and metabolic reprogramming as central to sorghum’s recovery and survival under episodic drought.

Drought Tolerance Mechanisms in Sorghum Genotypes publication trend

The graph below shows the total number of articles in drought tolerance mechanisms in sorghum genotypes across all publications each year (not limited to Nature Index journals).

Technical terms

Osmotic adjustment: The accumulation of solutes in cells to retain water and maintain turgor under drought.

Reactive Oxygen Species (ROS): Highly reactive molecules produced during stress that can damage proteins, lipids and DNA.

Proteomics: The large‐scale study of proteins, including their expression, modifications and interactions.

Stay‐green phenotype: A trait where plants maintain chlorophyll and photosynthetic capacity during post‐flowering drought.

Quantitative Trait Locus (QTL): A genomic region associated with variation in a quantitative trait, such as drought tolerance.

References

1. Association between Reactive Oxygen Species, Transcription Factors, and Candidate Genes in Drought-Resistant Sorghum. International Journal of Molecular Sciences (2024).
2. Current advances in the molecular regulation of abiotic stress tolerance in sorghum via transcriptomic, proteomic, and metabolomic approaches. Frontiers in Plant Science (2023).
3. Sorghum in dryland: morphological, physiological, and molecular responses of sorghum under drought stress. Planta (2021).
4. Comparative physiological and root proteome analyses of two sorghum varieties responding to water limitation. Scientific Reports (2020).