Dissecting aerial branching in wheat triggered by photoperiod –temperature decoupling

Faci-Gómez, Isabel (2025) Dissecting aerial branching in wheat triggered by photoperiod –temperature decoupling. Doctoral thesis, University of East Anglia.

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Abstract

Wheat architecture is shaped by the activation or suppression of axillary meristems (AMs), regulated by both genetic and environmental cues. This thesis identifies and characterises an environmentally induced aerial branching phenotype in photoperiod-sensitive wheat genotypes, triggered by the decoupling of temperature and photoperiod during a narrow window in early reproductive development. Under warm short-day conditions, genotypes such as Triticum turanicum consistently release aerial AMs at upper stem nodes. The extent of branching varies, however, within photoperiod-sensitive genotypes. We developed a matrix-based scoring system to quantify this phenotype that allowed us to distinguish it from aerial branching in known wheat mutants (svp1vrt2; Li et al., 2021), suggesting AM release via distinct mechanisms.

To investigate the underlying molecular basis, we performed RNA-seq at two key developmental stages in contrasting genotypes under branching-inductive and control environments. We identified differential expression of developmental regulators (TRD1, FT2, FUL3) and coordinated repression of NF-YA transcription factors, potentially under miR169 control. Hormone-associated genes, especially in the ethylene, ABA, GA and SL pathways, also showed differential expression. Genes linked to genetically induced aerial branching in wheat/barley, including SVP1, VRT2, and MND1 (Walla et al., 2020), were not differentially expressed, further supporting a distinct regulatory route between environmentally induced branching and the previous mutants. These findings informed a proposed model for how environmental signals may trigger AM release.

To facilitate field-based climate response studies, we also designed and deployed a UK regulation-compliant T-FACE (Temperature-Free Air Controlled Enhancement) infrared heating system. This system consistently elevated canopy temperatures, with measurable phenotypic effects, providing a scalable platform for studying crop responses under realistic warming scenarios.

Together, these studies provide new insights into the environmental control of wheat architecture and establish tools for its further exploration under both controlled and field conditions, with relevance for understanding climate change impacts.

Item Type:	Thesis (Doctoral)
Faculty \ School:	Faculty of Science > School of Biological Sciences
Depositing User:	Kitty Laine
Date Deposited:	06 May 2026 10:08
Last Modified:	06 May 2026 10:08
URI:	https://ueaeprints.uea.ac.uk/id/eprint/102907
DOI:

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