# Genome-wide identification of the PI4P5K gene family in cotton and role of GhPI4P5K-D04-2 in salt stress tolerance

## TL;DR

This study identifies PI4P5K genes in cotton and shows that GhPI4P5K-D04-2 helps plants tolerate salt stress.

## Contribution

The study is the first to identify and functionally characterize the PI4P5K gene family in cotton, focusing on salt stress tolerance.

## Key findings

- 146 PI4P5K family members were identified in four cotton species and grouped into three subgroups.
- GhPI4P5K-D04-2 is a salt stress-responsive gene that enhances salt tolerance when overexpressed in Arabidopsis.
- Knockdown of GhPI4P5K-D04-2 in cotton increases salt stress sensitivity.

## Abstract

Phosphatidylinositol-4-phosphate 5-kinase (PI4P5K/PIP5K), a core regulator of phosphatidylinositol signaling pathways, exerts critical regulatory functions in plant cellular signaling networks and developmental processes, and stress response through its kinase activity. However, its functions in cotton are little reported.

To comprehensively analyze the PI4P5K gene family in cotton, Genome-wide identification was performed to identify cotton PI4P5K family members and analyzed their gene structure, chromosome distribution, systematic evolution and collinearity, and transcript profiles under salt stress. Moreover, we studied function of GhPI4P5K-D04-2 by transforming it into Arabidopsis and using virus-induced gene silencing (VIGS) system.

In this study, we identified 146 PI4P5K family members from four cotton species (G. arboreum, G. raimondii, G. barbadense and G. hirsutum) via genome-wide screening, which were phylogenetically divided into three distinct subgroups. Structural domain analysis revealed conserved PIPKc superfamily domain in all proteins, while chromosomal mapping demonstrated syntenic distribution patterns between subgenomes A and D. Integrated transcriptomic and qRT-PCR analyses uncovered GhPI4P5K-D04-2 as a salt stress-responsive gene. Functional characterization assays demonstrated that overexpressing the GhPI4P5K-D04-2 gene exhibited enhanced tolerance to salt stress in Arabidopsis, whereas cotton plants with GhPI4P5K-D04-2 knockdown via VIGS showed increased sensitivity to salt stress.

In conclusion, the findings in this study about PI4P5K gene family and GhPI4P5K-D04-2 gene could lay a foundation for future studies of the biological functions of the cotton PI4P5K genes, and provide a theoretical basis for targeting improvement of cotton salt resistance through genetic manipulation of PIPK pathway.