Multi-omics analysis reveals the role of L-Glutamate in regulating cold tolerance of postharvest prune fruit

Abstract

Prune fruit tends to chilling injury (CI) under refrigeration after harvest, causing a remarkable quality decline. The L-glutamate (L-Glu) has been confirmed to be involved in regulating chilling resistance in postharvest prune fruit, but the underlying molecular mechanisms remain unknown. In this work, we found that L-Glu application mitigated the CI of prunes under refrigeration, accompanied by lower levels of ROS, internal browning index, malondialdehyde (MDA) content, as well as higher soluble sugar content, amino acids content, total phenolic content, flavone content. Furthermore, metabolomic and transcriptomic analyses were conducted to comprehensively reveal the variations of metabolic and transcriptional in prune fruit during CI development. In total, 490 differentially accumulated metabolites (DAMs) and 6831 differentially expressed genes (DEGs) were identified, and these DAMs and DEGs were mainly enriched in the biosynthesis of amino acids and secondary metabolites pathways. Moreover, the weighted correlation network analysis (WGCNA) was performed to establish a gene-metabolite correlation network, which uncovered the crucial transcription factors, structural genes, and metabolites correlated to amino acids and phenolics biosynthesis pathways of prune fruit regulated by L-Glu during CI development. Overall, these results implied that L-Glu could trigger the amino acids and phenolic synthesis pathways to attenuate CI of prune fruit, which supplies new information on the regulatory mechanism of L-Glu-improved chilling resistance of postharvest prunes.