Silencing Proline Dehydrogenases Improves Salt and Drought Tolerance in Gossypium hirsutum

Proline is a key compound that lowers cell water potential, scavenges reactive oxygen species, and stabilizes biomolecules and cell membranes, thus reducing stress-induced damage. Proline dehydrogenase (ProDH), the first rate-limiting enzyme in proline degradation, plays a crucial role in proline accumulation. We explored the role of the GhProDH gene family in regulating physiological responses to stress conditions through transcriptome, metabolome and functional analyses. Overexpression and gene silencing lines in Arabidopsis and cotton revealed that GhProDH2 plays a key role in regulating cottons tolerance to drought and salt stress. GhProDH2-4 improves cottons tolerance to drought and salt stress by engaging in carbon metabolism, glyoxylate cycle, and flavonoid metabolism pathways. These findings highlight the potential role of GhProDH2-4 to improve cotton stress resistance by genetically modifying pathways involved in proline biosynthesis and degradation.