Integrated transcriptomics, proteomics, and metabolomics identified biological processes and metabolic pathways involved in heat stress response in jojoba

Jojoba is an emerging industrial oil crop with excellent heat stress tolerance. However, the molecular mechanism underlying the heat tolerance of jojoba is not clear. In the present study, a combination of physiological and multi-omics techniques was used to investigate the metabolic pathways and the relevant molecular mechanisms associated with the heat stress response in jojoba leaves. A total of 1660 differentially abundant proteins and 3912 differentially expressed genes were identified by proteomic and transcriptomic analyses, respectively, in heat-stressed jojoba leaves. GO and KEGG analysis revealed protein folding and sorting, photosynthesis, calcium and MAPK signal pathway, ROS scavenging, energy metabolism, and carbohydrate metabolism were closely related to the heat stress response of jojoba. Metabolomics analysis showed that the content of 99 metabolites were changed significantly, among which the content of turanose, agmatine, xanthine, linolenic acid, and L-phenylalanine increased markedly in jojoba under heat stress. Multi-omics analysis revealed that the soluble sugars like galactinol and raffinose and free amino acids like tyrosine played important roles in maintaining the osmotic balance and alleviating the damage caused by heat stress via regulating carbohydrate and amino acid metabolism pathways. Our research identified the key proteins and metabolites involved in response to heat stress in jojoba, and provided genetic resources for the cultivation of heat tolerant crops.