Identification of CsAFP3-like as a novel gene regulating determinate growth of lateral branch in cucumber

Fan Yang, Yan Xu, Zichun Wang, Biao Dong, Siwen Zhou, Minying Jiang & Ji Li

Theoretical and Applied Genetics; November 18 2025; vol. 138; article 306

Key message

The CsaV3_1G006020 (CsAFP3-like) gene, which controlled determinate growth of lateral branch in cucumber via the ABA signaling pathway, was identified.

Abstract

Lateral branching is a critical agronomic trait in cucumber that directly influences plant architecture and crop yield. Therefore, understanding the genetic mechanisms underlying this trait is essential for effective cucumber breeding. Here, we identified a branchless mutant, designated mbl (mutant-branchless), exhibiting extremely determinate growth of lateral branch. Using BSA-seq analysis with four DNA bulk pools derived from an F₂ population crossing between mbl and a normal lateral branching variety, EC1, we mapped distinct loci associated with the lateral branch development. The A-Det (Main axis-determinate growth) was localized to chromosome 6 and corresponded to the previously reported CsTFL1 gene. The B-NDI (Lateral branch-node differentiation inhibiting) locus was located on chromosome 3, with the candidate region narrowed down to 3.03 Mb. The B-det (Lateral branch-determinate growth) was fine-mapped to a 391.74 kb interval on chromosome 1, within which only one non-synonymous mutation was found in CsaV3_1G006020 (CsAFP3-like). CsAFP3-like encoded an ABA INSENSITIVE 5 (ABI5) binding protein, of which the mutation located in the conserved ABI5 binding domain. CsAFP3-like expression was significantly decreased in leaf axils of mbl compared to EC1, where the endogenous ABA was dramatically accumulated. The CsAFP3-like VIGS experiment in cucumber confirmed its role in regulating determinate growth of lateral branch. These findings suggest that CsAFP3-like positively regulates ABA-mediated inhibition of lateral branch development.

See: https://link.springer.com/article/10.1007/s00122-025-05094-5