Physiological and Transcriptomic Insi Ghts into Salt and Saline-Alkali Stress Responses in Grafted Cabernet Sauvignon

Abstract

Grafting is a key technology for improving grapevine resistance, yet the mechanism underlying scion salt and saline-alkali stress responses after grafting remains unclear. In this study, we compared the responses of self-grafted Cabernet Sauvignon seedlings (CS/CS) and Cabernet Sauvignon grafted onto the resistant rootstock 1103P (CS/1103P) under salt and saline-alkali stress using morphophysiological assessments combined with transcriptome sequencing analysis. The results showed that saline-alkali stress inhibited plant growth more severely than salt stress, caused chlorophyll degradation and membrane damage, and significantly disrupted root ion homeostasis. Transcriptome analysis revealed significant differential gene expression patterns between CS/CS and CS/1103P under both stress conditions, which was mainly involved in ion transport, hormone signaling, and organic acid metabolism. Salt and saline-alkali stresses had markedly different effects on grapevine physiology. The 1103P rootstock maintained intracellular pH homeostasis through specific activation of the organic acid metabolism pathway and significantly upregulated the expression of the Na+/H+ antiporter (NHX) gene, effectively restricting Na+ translocation to aerial parts, thereby mitigating stress-induced damage, and outperforming self-grafted seedlings. These findings confirm the critical role of resistant rootstocks in enhancing grapevine stress tolerance and provide a theoretical basis for improving crop resilience in saline-alkali soils.

Keywords: Cabernet Sauvignon, grafting, salt stress, saline stress, organic acids