Transcriptome and metabolome analyses reveal that GA3ox regulates the dwarf trait in mango (Mangifera indica L.)

Mango is a tropical fruit with high economic value. The selection of suitable dwarf mango varieties is an important aspect of mango breeding. However, the mechanisms that regulate mango dwarfing remain unclear. In this study, we compared the transcriptomes and metabolomes of mango varieties Guiqi (a dwarfed variety) and Jinhuang (an arborized variety). A total of 4,954 differentially expressed genes and 317 differentially abundant metabolites were identified between the two varieties, revealing the molecular mechanism of the gibberellin 3β-hydroxylase gene GA3ox in regulating dwarfing traits in mangoes using joint transcriptome and metabolome analyses. The results showed that differentially expressed genes were enriched in the diterpenoid biosynthesis pathway and that differentially abundant metabolites were annotated to their upstream pathway, the terpenoid backbone biosynthesis. A gene regulation network based on these two pathways was constructed, indicating the upregulation of the GA3ox gene and the accumulation of gibberellin in dwarfed mangoes. We then transferred the GA3ox gene to tobacco plants following the application of gibberellin, and the morphology and height of the transgenic tobacco plants largely recovered the phenotype. These results demonstrated that GA3ox plays a role in the regulation of dwarf traits. Our study provides an important theoretical basis for studying the regulatory mechanisms underlying mango dwarfism to facilitate mango breeding.