# Reproductive development in Trithuria submersa (Hydatellaceae: Nymphaeales): the involvement of AGAMOUS-like genes

## TL;DR

This study explores the role of AGAMOUS-like genes in flower development in Trithuria submersa, an early angiosperm, shedding light on reproductive evolution.

## Contribution

The study identifies and characterizes three AGAMOUS-like genes in Trithuria submersa, revealing their distinct expression patterns in flower organs and ovules.

## Key findings

- TsAG1 and TsAG2 are expressed in bracts and other flower organs.
- TsAG3 shows ovule-specific expression, suggesting a D-type function.
- The study provides insights into AGAMOUS gene evolution in early angiosperms.

## Abstract

In the early diverging angiosperm Trithuria submersa
TsAG1 and TsAG2 are expressed in different flower organs, including bracts, while TsAG3 is more ovule-specific, probably functioning as a D-type gene.

Species of Trithuria, the only genus of the family Hydatellaceae, represent ideal candidates to explore the biology and flower evolution of early diverging angiosperms. The life cycle of T. submersa is generally known, and the “reproductive units” are morphologically well described, but the availability of genetic and developmental data of T. submersa is still scarce. To fill this gap, a transcriptome analysis of the reproductive structures was performed and presented in this work. This analysis provided sequences of MADS-box transcription factors, a gene family known to be involved in flower and fruit development. In situ hybridization experiments on floral buds were performed to describe the spatiotemporal expression patterns of the AGAMOUS genes, revealing the existence of three AG genes with different expression domains in flower organs and in developing ovules. Trithuria may offer important clues to the evolution of reproductive function among early angiosperms and Nymphaeales in particular, and this study aims to broaden relevant knowledge regarding key genes of reproductive development in non-model angiosperms, shaping first flower appearance and evolution.

The online version contains supplementary material available at 10.1007/s00425-024-04537-5.