Branch crowns determine overall plant architecture in strawberry and directly influence flowering capacity, fruit size, and yield stability. Although strigolactones are well known for suppressing shoot branching in many plant species, their specific regulatory mechanisms in strawberry remain poorly defined. Abscisic acid, another key phytohormone, is traditionally associated with stress responses and bud dormancy, but its role in branch crown development has received limited attention. Most previous studies have focused on hormone biosynthesis, while hormone catabolism has been largely overlooked. Based on these challenges, it is necessary to conduct in-depth research to clarify how hormone signaling and metabolism interact to control branch crown formation in strawberry.
Researchers from Shenyang Agricultural University report new insights into strawberry branching regulation in a study published (DOI: 10.1093/hr/uhaf250) in Horticulture Research in 2025. Using woodland strawberry as a model system, the team investigated how strigolactone signaling influences branch crown development. Through genetic, molecular, and physiological analyses, they identified a receptor-mediated pathway that controls branching by modulating abscisic acid metabolism rather than its synthesis. The findings reveal a previously unrecognized hormonal interaction shaping plant architecture and fruit-related traits.
The study focused on FveDAD2, a gene encoding a strigolactone receptor in woodland strawberry. Plants with reduced FveDAD2 expression developed significantly more branch crowns, showed compact growth, and produced smaller fruits. Molecular analyses revealed that weakened strigolactone perception stabilized the downstream repressor protein FveSMXL7.
Rather than acting directly on hormone biosynthesis, FveSMXL7 suppressed the transcription of FveHB7, a homeobox transcription factor gene. Under normal conditions, FveHB7 represses FveABA8’OH1, which encodes an abscisic acid 8′-hydroxylase responsible for affecting abscisic acid (ABA) catabolism. When FveHB7 expression was reduced, transcription of FveABA8'OH1 increased, accelerating ABA degradation in shoot tips.
Lower ABA levels removed inhibitory constraints on axillary bud outgrowth, resulting in excessive branch crown formation. Importantly, external application of ABA suppressed branching and partially rescued the multi-branched phenotype, confirming that ABA levels directly regulate branch crown development. Together, these findings demonstrate that strigolactones control strawberry branching through a multi-step transcriptional cascade that fine-tunes hormone metabolism rather than hormone production.
“This work reshapes our understanding of hormonal control over plant architecture,” the researchers noted. “Instead of simply regulating how much hormone is produced, strawberry plants fine-tune branching by controlling how fast abscisic acid is broken down. By identifying the FveDAD2–FveSMXL7–FveHB7 regulatory module, we show that transcriptional regulation of FveABA8'OH1 plays a central role in balancing vegetative growth and reproductive development. This mechanism provides a new conceptual framework for improving crop architecture through hormone metabolism.”
Precise control of branch crown number is critical for optimizing strawberry yield and fruit quality. Excessive branching can reduce fruit size and sugar accumulation, while insufficient branching limits yield potential. By targeting genes such as FveDAD2, FveSMXL7, and FveABA8'OH1, breeders may achieve finer control over plant architecture without disrupting overall hormonal balance. Beyond strawberry, the newly identified mechanism highlights the importance of hormone catabolism in regulating plant form and productivity. The findings also suggest broader implications for improving stress resilience, as abscisic acid plays a central role in drought adaptation and growth regulation.
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References
DOI
10.1093/hr/uhaf250
Original Source URL
https://doi.org/10.1093/hr/uhaf250
Funding information
This work was supported by the National Natural Science Foundation of China (Grant No. 32130092) and the project of Liaoning Province Germplasm Innovation Grain Storage and Technology Special Program (2023020525-JH1/102-04).
About Horticulture Research
Horticulture Research is an open access journal of Nanjing Agricultural University and ranked number one in the Horticulture category of the Journal Citation Reports ™ from Clarivate, 2023. The journal is committed to publishing original research articles, reviews, perspectives, comments, correspondence articles and letters to the editor related to all major horticultural plants and disciplines, including biotechnology, breeding, cellular and molecular biology, evolution, genetics, inter-species interactions, physiology, and the origination and domestication of crops.