Transcriptome Analysis of Cold-Tolerant and Cold-Sensitive Strawberry Cultivars Reveals the Defense Mechanisms...

This study explores the molecular mechanisms underlying cold stress tolerance in the contrasting strawberry cultivars Queen Elisa (highly cold tolerant) and Camarosa (cold sensitive). Various physiological parameters were measured in these cultivars under cold stress and non-stress conditions. RNA-Seq was used to identify differentially expressed genes and enriched pathways involved in the plant response to cold stress. Biochemical data revealed that the cold-tolerant cultivar under cold stress had higher levels of soluble carbohydrates and proline compared to the cold-sensitive cultivar. Gene expression data demonstrated that cold-tolerance and cold-sensitive cultivars under cold stress modulated genes mainly involved in carbohydrate metabolism, hormone signaling, and secondary metabolism. GO and KEGG pathway enrichment data showed that cofactor biosynthesis, hormone signaling, and MAPK signaling were the most significantly enriched pathways in both cultivars. The transcription factors NAC, C2H2, ERF, MYB, WRKY, bHLH, DREB, CONSTANS-like, MADS, CCCH, and HY5, and several other key genes have been identified as closely associated with plant tolerance to cold stress. In particular, both contrasting cultivars respond similarly to cold stress, but the cold-tolerant cultivar exhibited a broader modulation of stress-related transcription factors and hormone signaling pathways, which were interpreted as a stronger molecular and biochemical response compared to the cold-sensitive cultivar. Furthermore, several key genes are suggested to be associated with plant tolerance and are proposed as potential targets for the development of biotechnological tools based on transgenesis and genome editing in strawberries. Therefore, this research provides new insights into the genetic and molecular basis of strawberry tolerance to cold stress.