Integrative regulation of axillary meristem maturation and stolon fate determination in strawberry by light, gibberellin, and ZFP6

Résumé fourni par la source

The strawberry axillary meristem can develop into a branch crown (a flowering shoot) or a stolon (a horizontal stem that produces daughter plants), with gibberellin promoting stolon fate. Despite its importance for plant architecture, asexual reproduction, and perennial growth, the regulatory mechanism governing this fate decision remains poorly understood. In this study, we found that the juvenile-to-adult transition of the axillary meristem is marked by induction of GA20ox4 expression and the onset of stolon formation. RNA sequencing of staged meristems identified the zinc-finger protein ZFP6, which is strongly co-expressed with GA20ox4. CRISPR-mediated knockout of ZFP6 abolished GA20ox4 expression and eliminated stolon formation, a phenotype rescued by exogenous gibberellin, demonstrating that ZFP6 acts to activate gibberellin biosynthesis and promote stolon formation. Genetic analysis of mutants in the red-light receptor PhyB, together with mutants in gibberellin biosynthesis and signaling, further revealed that red light and PhyB promote axillary meristem maturation, a previously unrecognized developmental stage that precedes fate determination. Taken together, these findings illuminate how developmental stage and environmental cues converge to regulate axillary meristem maturation and fate determination, and identify a stage-specific regulator controlling the switch to stolon formation.

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