Structural and coding variation in PHYTOCHROMES A and C underlies differences in flowering time and shade avoidance
Sai Thejas Babanna1, Yogev Burko2, Björn Christopher Willige3
1Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstr. 3, OT Gatersleben, 06466 Seeland, Germany.
Biorxiv : the Preprint Server for Biology
|May 7, 2026
Summary
Wheat plant development is affected by light. Researchers identified key genes, PHYTOCHROME C (PHYC-A) and PHYTOCHROME A (PHYA-B), influencing traits like flowering time and plant height under shade, crucial for crop improvement.
Area of Science:
- Plant genetics and photobiology
- Agricultural science and crop improvement
Background:
- Plant architecture and development are sensitive to light availability, particularly in dense crops where shading alters light intensity and spectrum.
- Understanding the genetic control of these light responses in wheat is crucial for optimizing crop yields and architecture.
Purpose of the Study:
- To investigate the genetic basis of wheat responses to light availability, focusing on phenological and morphological traits under varying light conditions.
- To identify specific genes and genetic variations controlling developmental plasticity in response to canopy shade.
Main Methods:
- Utilized a Recombinant Inbred Lines (RILs) population to study traits under sunlight and simulated canopy shade.
- Employed quantitative trait locus (QTL) analysis on chromosome 5A and analyzed a tetraploid wheat diversity panel.
- Conducted functional analysis using TILLING-derived phytochrome mutants.
Main Results:
- Identified a major QTL on chromosome 5A with light-dependent allelic effects, linked to a structural rearrangement involving PHYTOCHROME C (PHYC-A) and VERNALIZATION-1 (VRN-A1).
- Natural variation in PHYC-A and PHYTOCHROME A (PHYA-B) on chromosome 4B associated with differences in heading time in tetraploid wheat.
- Confirmed distinct roles for PHYA and PHYC in regulating flowering time, plant height, and leaf elongation under simulated shade.
Conclusions:
- Phytochrome gene variations significantly contribute to developmental plasticity in wheat under canopy-like light environments.
- These findings provide insights into light-mediated developmental regulation, relevant for improving wheat architecture and performance in high-density cropping systems.
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