# GhA01EP1 of Upland Cotton Stimulates Precocity, Improved Water Deficit Tolerance, and High Seed Yield in Transgenic Arabidopsis

## TL;DR

A gene from upland cotton, GhA01EP1, when introduced into Arabidopsis, improves early flowering, drought tolerance, and seed yield.

## Contribution

The study reveals the novel role of GhA01EP1 in enhancing plant precocity, drought resistance, and seed yield in transgenic Arabidopsis.

## Key findings

- GhA01EP1-transgenic Arabidopsis showed earlier flowering, more branching, and higher seed yield compared to wild-type plants.
- Transcriptome analysis linked GhA01EP1 to genes involved in circadian rhythm, flowering, and stress response pathways.
- Transgenic plants exhibited higher glyoxalase I activity and lignin content, and lower malondialdehyde and starch under drought stress.

## Abstract

Background: The GhA01EP1 gene in upland cotton encodes an epidermal-specific secreted glycoprotein, whose functional characterization remains unexplored beyond our initial discovery of its water deficit resistance association. Therefore, we further designed experiments to investigate the functional role of GhA01EP1. Methods: We sequenced and analyzed the transcriptomes of wild-type (Col-0) and GhA01EP1-transgenic Arabidopsis thaliana. The differences in morphological and biochemical indicators were examined. In addition, the proteins interacting with GhA01EP1 in Arabidopsis were screened using a glutathione-S-transferase pull-down assay. Results: The GhA01EP1-transgenic Arabidopsis plants flowered earlier, produced more branches, and had a higher seed yield than Col-0. Transcriptome analysis revealed that differentially expressed genes detected in the comparison of GhA01EP1-transgenic and Col-0 Arabidopsis under the water treatment (the control) were associated especially with circadian rhythm regulation, photoperiodic flowering reaction, hormone metabolism, glyoxalase I synthesis, antioxidant pathway, branching development, and carbon-nitrogen allocation. Under water-sufficient or water-deficient treatments, the glyoxalase I activity and lignin content of GhA01EP1-transgenic Arabidopsis were significantly higher. Under water deficit stress, the malondialdehyde and starch contents were significantly lower, while peroxidase activity and protein content were significantly higher than those of Col-0. Conclusions: GhA01EP1 synergistically improved the precocity, water deficit tolerance, and seed yield of GhA01EP1-transgenic Arabidopsis. Analysis of GhA01EP1 function provides a molecular basis for breeding improved cotton varieties.