# HsGA20ox1, HsGA3ox1, and HsGA2ox1 Are Involved in Endogenous Gibberellin Regulation Within Heracleum sosnowskyi Ovaries After Gibberellin A3 Treatment

## TL;DR

This study explores how gibberellin levels and related genes regulate fruit development in the invasive weed Heracleum sosnowskyi.

## Contribution

The study identifies specific GA-oxidase genes involved in gibberellin regulation and fruit growth in H. sosnowskyi.

## Key findings

- Twenty-seven HsGAox genes were identified and classified into subfamilies.
- GA3 treatment increased bioactive GA levels and HsGA3ox1 expression in ovaries.
- GA regulation is crucial for stable early fruit development in H. sosnowskyi.

## Abstract

This study aims to investigate the endogenous gibberellin levels and related genes analysis of noxious invasive weed Heracleum sosnowskyi. Genome-wide identification, phylogenetic analysis, conserved motif analysis, and gene structure characterization of GA-oxidases were performed. We analysed endogenous GAs levels and the expression of target HsGAoxs in response to GA3 within H. sosnowskyi developing ovaries. Twenty-seven HsGAoxs genes were identified, distributed across eleven chromosomes. Phylogenetic analysis classified proteins into the HsGA20ox, C19-HsGA2ox, and HsGA3ox subfamilies, facilitating functional predictions. Among the thirteen HsGA2ox protein members, there were no C20-GA2ox subfamily that distinguish H. sosnowskyi from other model plant species. The analysis of gene structure and conserved motifs confirmed the phylogenetic grouping and suggested that the evolutionary pattern was maintained within these subfamilies. The observed increase in precursor and bioactive GA levels provides evidence that they play a crucial role in promoting fruit growth. Ovary phenotypes reflected the timing of peak gibberellin levels, specifically during the cell expansion period. Exogenous GA3 treatment promoted HsGA3ox1 expression within both the central and lateral regions of the umbel ovaries. Overall, the results show that GA levels are precisely regulated by multiple HsGAox genes for stable early fruit development, and that disturbances in this stability affect fruit development. This opens up the possibility of investigating the role of GA in H. sosnowskyi fruit formation and developing measures for invasion control.