Molecular Mechanisms of Pod Development in Groundnut Systems

Pod development in groundnut (Arachis hypogaea) is governed by a complex interplay of genetic, hormonal and environmental cues. Following aerial flowering, the fertilised gynophore—or peg—elongates downward, penetrating the soil to initiate subterranean pod formation, a unique process known as geocarpy. Inside the soil, shifts in light and mechanical stimuli trigger extensive reprogramming of gene expression, involving key transcription factors, cell division regulators and hormone-related pathways. Auxin, cytokinin and gibberellin gradients coordinate cell proliferation during the rapid-growth stage, while calcium signalling acts as both nutrient and second messenger essential for embryo viability and shell development. Multi-omics approaches have revealed dynamic changes in transcriptomes, proteomes and phosphoproteomes that underpin tissue differentiation, stress adaptation and nutrient allocation. Hub genes identified through co‐expression networks govern processes from cell wall modification to stress resilience, linking molecular mechanisms with agronomic traits. Understanding these pathways provides a foundation for molecular breeding strategies aimed at improving yield, pod size and environmental adaptability in diverse agroecosystems.

Research from Nature Portfolio

A foundational transcriptome analysis of peanut kernels and shells under varying calcium regimes has illuminated early pod-development processes. Differential gene expression profiling demonstrated that calcium sufficiency enhances nutrient transport and signal transduction genes in the shell before impacting kernel formation. Key components of calcium-binding and hormonal signalling cascades were up-regulated in calcium-replete conditions, promoting shell expansion and subsequent seed development. This study established a molecular link between calcium availability and the sequential activation of shell and kernel gene networks, offering targets for improving low-calcium soil tolerance.

Molecular Mechanisms of Pod Development in Groundnut Systems publication trend

The graph below shows the total number of articles in molecular mechanisms of pod development in groundnut systems across all publications each year (not limited to Nature Index journals).

Technical terms

Geocarpy: The process by which flowers develop above ground and fruits mature underground.

Gynophore (peg): A specialised stalk that transports the fertilised ovary into the soil for pod formation.

Transcriptome: The complete set of RNA transcripts produced by the genome under specific conditions.

Proteome: The entire complement of proteins expressed in a cell, tissue or organism at a given time.

Phosphoproteome: The subset of proteins that are phosphorylated, reflecting dynamic regulatory modifications.

Phytohormone: A plant hormone that regulates growth, development and responses to environmental cues.

Differentially Expressed Gene (DEG): A gene whose expression level changes significantly between developmental stages or treatments.

References

1. Transcriptome of peanut kernel and shell reveals the mechanism of calcium on peanut pod development. Scientific Reports (2020).
2. Transcriptome profiling of aerial and subterranean peanut pod development. Scientific Data (2024).
3. Deciphering the Proteome and Phosphoproteome of Peanut (Arachis hypogaea L.) Pegs Penetrating into the Soil. International Journal of Molecular Sciences (2025).
4. The determination of peanut (Arachis hypogaea L.) pod-sizes during the rapid-growth stage by phytohormones. BMC Plant Biology (2023).