Genetic Mechanisms of Inflorescence Development in Cereal Crops

Inflorescence architecture in cereals underpins grain yield by determining the number, arrangement and fertility of spikelets. The developmental programme is governed by the activity and determinacy of inflorescence meristems, which transition from vegetative to reproductive states and initiate primary and secondary branches. Key regulators include MADS-box and homeodomain transcription factors, which specify meristem identity and floral organ fate, and hormonal pathways—particularly auxin and cytokinin signalling—that modulate branch initiation and outgrowth. Genome‐wide association and transcriptome analyses have revealed that both major‐effect and small‐effect loci, often acting through cis‐regulatory variants, converge on gene regulatory networks controlling meristem maintenance, lateral primordia formation and programmed floret abortion. Comparative studies across rice, maize, wheat and barley highlight conserved modules alongside species-specific innovations, such as unique floral organ specification genes and lineage-restricted regulators of branch number. Insights into the timing and spatial expression of causal genes have facilitated the identification of targets for allele selection and precise genome editing. By integrating functional genomics with breeding, researchers are harnessing variation in transcriptional regulators and hormone metabolism to optimise inflorescence form, enhance spikelet fertility and stabilise yield under diverse environmental conditions.

Research from Nature Portfolio

A large‐scale transcriptome‐wide association study in rice young panicles linked expression variation at thousands of genes to key architectural traits, identifying numerous small-effect cis‐regulatory variants that collectively determine spikelet number per panicle. Integration of cis- and trans-expression components enabled the prioritisation of putative causal genes—including specific MADS-box regulators—and the construction of underlying gene regulatory networks, with experimental validation of direct regulatory interactions influencing panicle branching. In maize, functional dissection of a serine/threonine protein kinase revealed its central role in controlling pistillate floret number and ear length. Overexpression or allele introgression that disrupts transposable‐element insertions in its regulatory region led to significant increases in kernel number per row, while biochemical assays demonstrated its interaction with GTPase-activating proteins, elucidating a mechanistic link between kinase activity and inflorescence development.

Genetic Mechanisms of Inflorescence Development in Cereal Crops publication trend

The graph below shows the total number of articles in genetic mechanisms of inflorescence development in cereal crops across all publications each year (not limited to Nature Index journals).

Technical terms

Inflorescence meristem: A specialised plant shoot apical meristem that generates branches and floral structures during the reproductive phase.

Panicle: A type of branched grass inflorescence bearing primary and secondary branches, each terminating in one or more spikelets.

Spikelet: The basic unit of grass inflorescences, composed of one or more florets subtended by bracts (lemma and palea).

Expression quantitative trait locus (eQTL): A genomic region where genetic variation influences the expression level of one or more genes, often used to link regulatory variants with phenotypic traits.

MADS-box transcription factor: A family of DNA-binding proteins that orchestrate floral organ identity, meristem determinacy and inflorescence architecture in plants.

References

1. Transcriptome-wide association analyses reveal the impact of regulatory variants on rice panicle architecture and causal gene regulatory networks. Nature Communications (2023).
2. Multilayered regulation of developmentally programmed pre-anthesis tip degeneration of the barley inflorescence. The Plant Cell (2023).
3. Major genes determining yield-related traits in wheat and barley. Theoretical and Applied Genetics (2017).
4. A serine/threonine protein kinase encoding gene KERNEL NUMBER PER ROW6 regulates maize grain yield. Nature Communications (2020).