Researchers Unlock Wheat's Water-Saving Potential with TabHLH27 Balancing Stress and Growth

Wheat plays a critical role in global food security, yet water scarcity in arid and semi-arid regions hampers its efficient production, signaling substantial water-saving opportunities. Therefore, understanding the genes governing wheat's drought tolerance and water use efficiency is crucial for enhancing genetic resilience and breeding water-efficient varieties.

In a recent study led by Professor XIAO Jun from the Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, researchers made new understanding on how TabHLH27 enhances wheat's drought tolerance and water use efficiency by balancing stress and growth.

Published in the Journal of Integrative Plant Biology, the research titled "TabHLH27 orchestrates root growth and drought tolerance to enhance water use efficiency in wheat" (https://doi.org/10.1111/jipb.13670) sheds light on TabHLH27's multifaceted regulation.

The study identified a shared genetic locus associated with drought tolerance during both the seedling and maturity stages, pinpointing TabHLH27-A1 as a key candidate through expression profile analysis. Knocking out TabHLH27 significantly reduced wheat's drought tolerance, spikelet number per spike, grain yield, and water use efficiency. TabHLH27's role involves dual transcriptional activity, activating stress response genes while repressing developmental genes, possibly through interactions with co-factors like TabZIP62-D1 and TaABI3-D1. Its dynamic expression under drought stress, rapidly induced yet declining over time, indicates a nuanced response for enhanced adaptation. Interaction with transcription factors like TaNAC29-A1 forms a hierarchical regulatory network crucial for wheat's response to water-limited environments.

Moreover, natural variation in the TabHLH27-A1 promoter region affected its transcriptional response to drought stress, with the TabHLH27-A1^Hap-II haplotype exhibiting superior drought tolerance, larger roots, higher yield, and water use efficiency. TabHLH27-A1 alleles' distribution in China correlates with rainfall, favoring the superior TabHLH27-A1^Hap-II in breeding due to its low frequency in modern varieties, signaling strong breeding potential. Backcrossing the superior haplotype into main wheat varieties improved drought tolerance, yield, and water use efficiency.

This study elucidates the molecular mechanism of TabHLH27 regulating wheat's drought tolerance and water use efficiency, deepening our understanding of wheat's response to drought stress and stress-growth balance, and providing essential gene resources and selection targets for breeding drought-resistant, water-saving, high-yielding wheat varieties.

 

 

 

Contact:

Dr. XIAO Jun

Institute of Genetics and Developmental Biology, Chinese Academy of Sciences

Email: jxiao@genetics.ac.cn