Biological role of red light supplementation in inositol metabolism during strawberry fruit ripening

Light supplementary has been widely employed in various agricultural facilities to regulate plant growth and development as well as to mediate the certain metabolic process associated with quality. Previous studies suggested that red light has a role in regulating sugar metabolism in strawberry fruit, but the underlying biological mechanism remains unknown. In this study, we investigated the effects of white and red lights on the sugar metabolism for strawberry fruit by using multi-omics and bioinformatics methods. We observed differential accumulation of D-Mannose-6-phosphate sodium salt, sorbitol, and inositol in strawberry fruits. Transcriptomic analysis revealed 3650 differentially expressed genes, and enrichment analysis of the differentially expressed genes for Gene Ontology enrichment and Kyoto Encyclopedia of Genes and Genomes pathways highlighted significant associations with phenylpropanoid biosynthetic process and galactose metabolism pathways. The results showed that 7 differentially expressed genes were involved in inositol metabolism pathway. Expression patterns of these genes were verified by qRT-PCR. Additionally, we constructed a co-expression network to identify various macromolecules including structural genes and key transcription factors involved in regulating galactinol synthase gene family members, including HD-ZIP proteins, NAC proteins, MYB proteins, and WRKY proteins, among others. Our study provides new insight into the regulation of inositol metabolism through red light supplementation in strawberry plants. Furthermore, we proposed the potential transcription factors that regulate galactinol synthase genes in inositol metabolism pathway. Our work offers theoretical support for the development of effective lighting strategies to enhance strawberry fruit quality.