bHLH Transcription Factors in Abiotic Stress Responses

Basic helix-loop-helix (bHLH) proteins constitute one of the largest families of transcription factors in plants, defined by a conserved basic region for DNA binding and a helix-loop-helix motif for dimerisation. These factors sense and integrate diverse environmental cues, modulating gene networks that underlie drought, salinity, cold and oxidative stress tolerance. By binding E-box or G-box cis-elements, bHLH dimers activate or repress target genes involved in osmolyte biosynthesis, antioxidant defence, hormone signalling and secondary metabolite production. Genome-wide surveys across major crops have revealed extensive expansion and divergence of bHLH subfamilies, with distinct expression patterns in roots, leaves and reproductive tissues. Functional studies demonstrate that specific bHLHs enhance resilience by promoting reactive oxygen species homeostasis, stabilising membranes, regulating C-repeat binding factor (CBF) pathways and fine-tuning abscisic acid responses. This mechanistic diversity highlights the potential of bHLH engineering for crop improvement under a changing climate.

Research from Nature Portfolio

No recent Nature Portfolio content available.

bHLH Transcription Factors in Abiotic Stress Responses publication trend

The graph below shows the total number of articles in bhlh transcription factors in abiotic stress responses across all publications each year (not limited to Nature Index journals).

Technical terms

bHLH transcription factor: A protein containing a basic region for DNA binding and a helix-loop-helix motif that enables dimer formation and sequence-specific gene regulation.

Abiotic stress: Non-living environmental factors such as drought, salinity, temperature extremes and oxidative pressure that adversely affect plant growth.

Dimerisation: The process by which two bHLH monomers associate via their helix-loop-helix regions to form a functional DNA-binding complex.

cis-element: A short DNA sequence in gene promoters recognised by transcription factors to regulate gene expression.

Reactive oxygen species (ROS): Highly reactive molecules derived from oxygen that accumulate under stress and can cause cellular damage unless detoxified.

CBF pathway: A cold-responsive regulatory cascade in which C-repeat binding factors activate downstream genes conferring freezing tolerance.

References

1. Genome Wide Identification and Characterization of Apple bHLH Transcription Factors and Expression Analysis in Response to Drought and Salt Stress. Frontiers in Plant Science (2017).
2. Current Understanding of bHLH Transcription Factors in Plant Abiotic Stress Tolerance. International Journal of Molecular Sciences (2021).
3. Genome-Wide Identification and Characterization of the Potato bHLH Transcription Factor Family. Genes (2018).
4. Genome-wide identification and characterization of the bHLH gene family in tomato. BMC Genomics (2015).
5. Genome-Wide Characterization of bHLH Genes in Grape and Analysis of their Potential Relevance to Abiotic Stress Tolerance and Secondary Metabolite Biosynthesis. Frontiers in Plant Science (2018).
6. Genome-wide analysis of the basic Helix-Loop-Helix (bHLH) transcription factor family in maize. BMC Plant Biology (2018).
7. The transcription factor CsbHLH18 of sweet orange functions in modulation of cold tolerance and homeostasis of reactive oxygen species by regulating the antioxidant gene. Journal of Experimental Botany (2018).
8. Overexpression of EcbHLH57 Transcription Factor from Eleusine coracana L. in Tobacco Confers Tolerance to Salt, Oxidative and Drought Stress. PLOS ONE (2015).
9. Tobacco Transcription Factor NtbHLH123 Confers Tolerance to Cold Stress by Regulating the NtCBF Pathway and Reactive Oxygen Species Homeostasis. Frontiers in Plant Science (2018).
10. Regulatory Mechanisms of bHLH Transcription Factors in Plant Adaptive Responses to Various Abiotic Stresses. Frontiers in Plant Science (2021).