Genetic Regulation and Molecular Basis of Plant Abiotic Stress Tolerance

Dear Colleagues,

Abiotic stresses—including drought, salinity, extreme temperatures (heat and cold), flooding, and heavy metal toxicity—represent major constraints on global agricultural productivity. These stresses are threatening food security for a growing world population. Plants have evolved intricate genetic and molecular mechanisms to perceive environmental cues, transduce signals, and activate adaptive responses that enhance survival and productivity under adverse conditions. Understanding these mechanisms is essential for developing stress-resilient crop varieties.

Plant Genetic Tolerance to Abiotic Stress

Genetic tolerance to abiotic stress involves both avoidance and true tolerance strategies. These include morphological adaptations (e.g., deeper root systems or altered leaf architecture), physiological adjustments (e.g., stomatal regulation and osmotic adjustment via accumulation of compatible solutes such as proline, glycine betaine, or trehalose), and biochemical defenses (e.g., enhanced antioxidant systems to mitigate reactive oxygen species, ROS). At the genetic level, tolerance is a complex polygenic trait. Quantitative trait loci (QTLs) governing component traits have been mapped in major crops such as rice, wheat, maize, and tomato. Wild relatives and landraces often serve as valuable sources of novel alleles for stress tolerance, which can be introgressed into elite cultivars. Multi-omics approaches (genomics, transcriptomics, proteomics, and metabolomics) have accelerated the identification of stress-responsive genes and their interactions under single or combined-stress conditions.

Mechanisms of Gene Regulation

Gene regulation under abiotic stress operates through sophisticated transcriptional, post-transcriptional, translational, and epigenetic networks. Stress signals are perceived by sensors (e.g., membrane receptors or calcium channels) and transduced via secondary messengers such as calcium ions, reactive oxygen species, and phytohormones—particularly abscisic acid (ABA). Transcription factors (TFs) serve as master regulators. Key families include the following:

AP2/ERF (e.g., DREB/CBF genes):

Central to cold and dehydration responses, they bind to dehydration-responsive elements (DREs) and activate downstream genes like COR (cold-regulated) or LEA (late embryogenesis abundant) proteins.

bZIP (e.g., AREB/ABF):

ABA-dependent regulators that bind to ABRE (ABA-responsive elements).

NAC, MYB, WRKY, and bHLH:

These orchestrate broad responses, including osmotic adjustment, antioxidant defense, and crosstalk between stresses.

These TFs (and others not mentioned) form complex regulatory networks with cis-elements in promoters and interactions with other TFs or co-regulators. Epigenetic mechanisms—such as DNA methylation, histone modifications (acetylation, methylation), and chromatin remodeling—further fine-tune gene expression and can establish stress memory to enable faster responses to recurrent stressors.

Post-transcriptional regulation involves microRNAs (miRNAs), small interfering RNAs (siRNAs), and alternative splicing, while post-translational modifications (e.g., phosphorylation by kinases like SnRK2s or MAPKs) modulate protein activity and stability. Hormone signaling pathways (ABA, ethylene, jasmonic acid, etc.) integrate these responses, enabling crosstalk that allows plants to prioritize resources under combined stresses.

Supporting Future Crop-Stress-Resistance Breeding

Advances in functional genomics, genome-wide association studies (GWAS), and precise genome-editing tools like CRISPR/Cas9 have transformed breeding strategies. These enable targeted modification of key regulators (e.g., editing OsRR22 or TaHKT1;5 for salinity tolerance) without linkage drag or pyramiding multiple QTLs/TFs for broad-spectrum resilience. Marker-assisted selection (MAS), genomic selection, and speed breeding further accelerate the development of high-yielding, stress-tolerant varieties.

However, challenges remain: translating lab discoveries to field performance, managing trade-offs between stress tolerance and yield under optimal conditions, and addressing combined stresses that mimic real-world scenarios. Integrated multi-omics and systems biology approaches, combined with high-throughput phenotyping, are critical for overcoming these hurdles. This Special Issue brings together cutting-edge research on the genetic regulation and molecular basis of plant abiotic stress tolerance. It highlights novel genes, regulatory networks, epigenetic insights, and translational applications. We hope these contributions will advance fundamental understanding and provide practical tools and strategies to support breeders and researchers in developing environmental and climate-resilient crops, ultimately contributing to sustainable agriculture and global food security.

We sincerely invite the scientific community to contribute articles and engage in thorough discussions in this section.

Dr. Zhiming Yu
Dr. Yifeng Wang
Guest Editors

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• abiotic stress
• receptors
• calcium channels
• secondary messengers
• reactive oxygen species
• phytohormone metabolism
• transcription factors
• epigenetic mechanism
• RNA signaling
• hormone-signaling pathways
• functional genomics
• genome-wide association studies
• precise genome-editing tools
• integrated multi-omics
• systems biology