Our lab studies how the spike, the grain-bearing inflorescence of the wheat plant develops. Understanding the molecular mechanisms and gene networks that control spike development is important for elucidating how grain number is regulated and for improving wheat productivity.
Recent work from our lab includes in-depth spatial and single-cell transcriptomic analyses of gene expression domains from early through floret primordia stage (Xu et al. 2025 Genome Biology).
We also contributed to the characterization of gene regulatory networks controlling the timing and rate of inflorescence development (VanGessel et al. 2022 Scientific Reports).
Initiation of the spike development
Spike development is initiated through the transition of the vegetative shoot apical meristem that produces leaves into an inflorescence meristem that produces spikelets.
MADS-box genes essential roles in these transitions that have been investigated in two studies from our lab:
- Wheat VRN1, FUL2 and FUL3 play critical and redundant roles in spikelet development and spike determinacy (Li et al. 2019 Development).
- Interactions between SQUAMOSA and SHORT VEGETATIVE PHASE MADS-box proteins regulate meristem transitions during wheat spike development (Li et al. 2021 TPC)
Regulation of the spikelet number
The spikelet number is determined by the timing and rate of inflorescence meristem development before the transition to a terminal spikelet. Numerous developmental genes, many of which are modulated by SQUAMOSA MADS-box genes, are active in these processes.
- WAPO-A1 is the causal gene of the 7AL QTL for spikelet number per spike in wheat (Kuzay et al 2022, Plos Genetics)
- LEAFY and WAPO1 jointly regulate spikelet number per spike and floret development in wheat (Paraiso et al. 2024 Development)
- Natural alleles of LEAFY and WAPO1 interact to regulate spikelet number per spike in wheat (Zhang et al. 2024 TAG)
- FLOWERING LOCUS T2 regulates spike development and fertility in temperate cereals (Shaw et al. 2019 J exp Bot).
- Wheat bZIPC1 interacts with FT2 and contributes to the regulation of spikelet number per spike (Glenn et al. 2023 TAG)
- Identification and characterization of a natural polymorphism in FT-A2 associated with increased number of grains per spike in wheat (Glenn et al. 2021 TAG)
Regulation of glume and lemma identity and its effect on threshability
- microRNA172 plays a crucial role in wheat spike morphogenesis and grain threshability (Debernardi et al. 2017 Development)
- APETALA 2‐like genes AP2L2 and Q specify lemma identity and axillary floral meristem development in wheat (Debernardi et al. 2019)
- FZP is required to repress the glume’s axillary meristem. The effect of fzp mutants are described in Xu et al. 2025 Genome Biology