Background
Global warming has made high–temperature stress one of the most important factors causing crop yield reduction and death. In the rose flower industry, high-temperature stress leads to bud dormancy or even death, reducing ornamental value and incurring in economic loss. Understanding the molecular mechanisms underlying the response and resistance of roses to high-temperature stress can serve as an important reference for the cultivation of high-temperature-stress-resistant roses.
Results
To evaluate the impact of high temperature on rose plants, we initially measured physiological indices in rose leaves after heat stress. We observed a significant decrease in protein and chlorophyll content, while proline and malondialdehyde (MDA) levels, as well as peroxidase (POD) activity, increased. Subsequently, transcriptomics and metabolomics analyses were conducted to detect changes in gene expression and metabolite content after high-temperature stress. Compared to the untreated control (T0), the number of differentially expressed genes (DEGs) and differentially abundant metabolites (DAMs) in rose plants subjected to heat peaked at time points T6-T9. This trend closely aligned with the observed physiological changes. Enrichment analysis showed that most DEGs and DAMs primarily involved in the mitogen-activated protein kinases (MAPK) signaling pathway, plant hormone signal transduction, alpha-linolenic acid metabolism, phenylpropanoid biosynthesis, flavonoid biosynthesis, etc.
After heat stress, the DEGs and DAMs combined analysis revealed a predominant downregulation of genes and metabolites related to the flavonoid biosynthesis pathway. Similarly, genes involved in the jasmonic acid pathway within the MAPK signaling pathway exhibited decreased expression, but genes associated with the ethylene pathway were mostly upregulated, suggesting a role in roses’ heat stress responses. Furthermore, heterologous overexpression of the heat stress-responsive gene RcHP70 in Arabidopsis thaliana increased resistance against heat stress.
Conclusion
The present study provides new insights on the genes and metabolites induced in roses in response to high temperature; the present results provide a reference for analyzing the molecular mechanism underlying resistance to heat stress in roses. The obtained candidate genes and metabolites could be valuable resources for breeding of heat stress resistant roses.
