# The PtDPL1/PtGAMYB-PtLEAFY module regulates pollen fertility and flowering time in Pinus tabuliformis

## TL;DR

This study identifies a genetic module in Chinese red pine that regulates pollen fertility and flowering time, offering new insights into conifer reproduction.

## Contribution

The discovery of a novel PtDPL1/PtGAMYB-PtLEAFY regulatory network in Pinus tabuliformis.

## Key findings

- PtGAMYB is localized in the nucleus and highly expressed in male cones and pollen.
- PtGAMYB delays flowering and reduces pollen germination in Arabidopsis, effects reversed by GA4 + 7.
- PtGAMYB interacts with PtDPL1 to regulate PtLEAFY and male cone formation.

## Abstract

Reproductive development is a crucial stage in the plant life cycle. The GAMYB transcription factor plays an important role in regulating stamen development. Here, PtGAMYB was identified as part of the GA signal transduction pathway of Pinus tabuliformis and demonstrated to play a role in male reproductive development. Subcellular localization assays revealed that the PtGAMYB protein is localized in the nucleus. Both RNA-seq and fluorescence in situ hybridization demonstrated that PtGAMYB is specifically and highly expressed in the male cones and pollen of Pinus tabuliformis. Heterologous expression of PtGAMYB in Arabidopsis thaliana delayed flowering time, reduced pollen germination rates, and impaired the seed set. However, these phenotypes could be restored by exogenous GA4 + 7 treatment. Additionally, binding and activation analyses indicated that PtGAMYB acts as an upstream regulator of PtLEAFY. Further studies determined that PtGAMYB interacts with PtDPL1 protein to enhance the inhibition of PtLEAFY, ultimately regulating male cone formation in Pinus tabuliformis. Our findings establish a novel PtDPL1/PtGAMYB-PtLEAFY regulatory network and provide new insights into the reproductive mechanisms in conifers.