Deciphering the PgLEA2-50 interactome: implications for abiotic stress responses in Panax ginseng.

Ginseng's prolonged development renders it susceptible to environmental stresses. Late embryogenesis abundant (LEA) proteins are essential for plant resistance to abiotic stress. Our previous study demonstrated that PgLEA2-50, a member of the LEA protein family, plays a significant role in stress resistance. In this study, we employed IP-MS, bioinformatics, and molecular interaction assays to investigate the mechanisms underlying its stress resistance. PgLEA2-50 formed complex networks with multiple interacting proteins, which were enriched in stress-related processes such as gibberellin (GA) signal transduction, saponin biosynthesis, and the oxidative stress response. Transcriptome analysis revealed that its interacting targets exhibited significant responses to abiotic stress at the transcriptional level. An investigation of the DELLA protein PgRGA4 showed that it was down-regulated following GA induction, with its transcriptional activity inhibited under stress conditions. PgRGA4 was found to be localized in both the nucleus and cytoplasm, and co-immunoprecipitation (CO-IP) confirmed its interaction with PgLEA2-50, suggesting that PgLEA2-50 indirectly regulates GA-mediated stress resistance. This study provides a ginseng-specific case for the role of LEA proteins in stress resistance and identifies a novel gene target for molecular breeding in medicinal plants.