# De Novo Transcriptome Profiling of Salt Stress Responses in the Crop Wild Legume Vicia hirsuta (L.) Gray

## TL;DR

This study explores how the wild legume Vicia hirsuta responds to salt stress at the genetic level, offering insights into improving crop resilience to salty soils.

## Contribution

The study provides a de novo transcriptomic resource for Vicia hirsuta, revealing key genes and pathways involved in salt stress adaptation.

## Key findings

- Salt stress in Vicia hirsuta activates genes related to signaling, transcription factors, and ion transporters.
- Genes involved in Na+/K+ balance are consistently up-regulated under salt stress.
- Transcription factor families like bHLH, MYB, bZIP, NAC, and WRKY are key regulators during stress adaptation.

## Abstract

Soil salinity is an increasing agricultural challenge that limits crop growth and yield worldwide. As salinity stress becomes more widespread, crop wild relatives are gaining attention as genetic resources for improving stress tolerance, but molecular information for many wild species remains limited. In this study, we analyzed genome-wide gene expression in Vicia hirsuta (L.) Gray (hereafter referred to as V. hirsuta), a wild legume relative, after seven days of salt stress. The results revealed coordinated changes in stress-related signaling, transcription factor activity, and ion transporter genes, particularly those involved in Na+ and K+ balance, while antioxidant enzyme responses indicated that plants experienced stress. This study provides a foundational transcriptomic resource for V. hirsuta and highlights the potential value of wild legumes for improving salt stress tolerance in cultivated crops.

Salt stress is a major environmental constraint affecting plant growth and productivity. Crop wild relatives provide valuable genetic resources for stress tolerance, yet transcriptomic information for forest-derived wild species remains limited. In this study, we analyzed transcriptional responses of V. hirsuta, a crop wild relative (CWR) of legumes, after seven days of salt stress using de novo transcriptome sequencing. Seedlings were exposed to salt stress, and differentially expressed genes (DEGs) were identified between control (Vh_S0) and salt-treated (Vh_S7) plants using an FDR-adjusted threshold (q < 0.05). Gene Ontology and KEGG enrichment analyses revealed that salt-responsive DEGs were mainly involved in regulatory signaling, metabolic adjustment, redox-related processes, and macromolecular organization. Up- and down-regulated DEGs showed distinct yet overlapping enrichment patterns, indicating complex transcriptional reprogramming under salt stress. Transcription factor analysis identified bHLH, MYB, bZIP, NAC, and WRKY families as major regulators, with many families containing both up- and down-regulated members. Notably, genes associated with Na+/K+ homeostasis were consistently up-regulated and validated by qRT-PCR. These results suggest that continuous seven days salt stress adaptation in V. hirsuta involves coordinated regulation of signaling pathways, transcriptional networks, and transporter-mediated ion homeostasis, providing a valuable transcriptomic resource for crop wild relatives.