Single boll weight and seed size are key determinants of cotton yield, but the genetic mechanisms behind these traits have remained elusive. A study published in Molecular Genetics and Genomics identifies a single nucleotide polymorphism in the promoter of the gene OFP17 as a causal variant governing both traits, building on the team’s earlier finding that OFP17 regulates boll and seed sizes in an introgression line of Gossypium arboreum carried within a Gossypium hirsutum background.

The researchers used virus-induced gene silencing and virus-induced gene overexpression of OFP17 in cotton, and ectopic expression of OFP17 in Arabidopsis thaliana. The results indicated that OFP17 negatively regulates boll and seed sizes.

Promoter activity assays revealed that a SNP in the OFP17 promoter was the causal variant, regulating promoter activity and the OFP17 gene expression level, consistent with its phenotypic differences.

To probe the molecular mechanism, the team combined yeast two-hybrid assays, bimolecular fluorescence complementation and subcellular localization. These showed that OFP17 physically interacts with the transcription factor GhNF-YC4, which in turn interacts with the DELLA protein GhGAI, a repressor of gibberellin signaling.

Intriguingly, overexpression of GaOFP17 in Arabidopsis led to hypersensitivity to abscisic acid during seed germination, accompanied by upregulation of AtNF-YC4, AtGAI and the ABA-responsive gene AtABI5.

In conclusion, the authors propose a model in which OFP17, via interaction with NF-YC4, may modulate a DELLA-dependent transcriptional network that integrates gibberellin and ABA signaling to control boll and seed sizes. These findings provide new insights into the transcriptional regulation of boll and seed sizes and suggest potential genetic targets for improving cotton yield.

Subject of Research: A promoter SNP regulating the OFP17 gene and its interaction with NF-YC4 in the control of cotton boll and seed size

Article Title: A promoter SNP enhancing GaOFP17 expression in upland cotton reduces cotton boll and seed sizes via interaction with NF-YC4

Article References: Xu, M., Feng, L., Zhang, Z., Liu, S., Feng, G., Wang, N., Ai, N., & Zhou, B. (2026). A promoter SNP enhancing GaOFP17 expression in upland cotton reduces cotton boll and seed sizes via interaction with NF-YC4. Molecular Genetics and Genomics, 301(1), Article 211. https://doi.org/10.1007/s00438-026-02546-5

Image Credits: AI Generated

DOI: 10.1007/s00438-026-02546-5

Keywords: cotton, OFP17, promoter SNP, boll size, seed size, NF-YC4, DELLA protein, gibberellin, abscisic acid, Gossypium hirsutum, transcriptional regulation, yield traits