Improvement of plant tolerance to salt stress by GhRL192 mRNA through long-distance movement

Salt stress poses a major restricting factor for sustainable agricultural development, limiting crop productivity and adversely affecting crop productivity. Grafting is a commonly used technique to improve the quality and stress resilience of horticultural crops. However, limited research has utilized grafting to explore the role of key mobile mRNAs in response to salt stress for molecular breeding applications. In this study, grafting systems were established between cotton and okra or tobacco. Through these systems, the 60S Ribosomal Protein L19-2 (RL192) mRNA was identified as a mobile molecule moved from cotton (rootstock) to okra (scion). Fluorescence quantification and beta-glucuronidase (GUS) staining analyses showed that GhRL192 expression was significantly induced by salt stress. Silencing GhRL192 in cotton significantly reduced salt stress tolerance, whereas overexpression of GhRL192 in tobacco or Arabidopsis improved seed germination and root development and the survival rate of seedlings under salt stress. This novel grafting strategy between horticultural and agricultural crops provides new insights and methodologies for studying mobile mRNAs that enhance crop stress resistance, yield, and quality. The identification and analysis of GhRL192 mRNA in relation to salt tolerance confirmed the feasibility of this approach, laying the groundwork for further exploration of transport mechanisms and molecular regulatory networks.