Genome-wide investigation of sucrose synthase gene family in pineapple: Characterization and expression profile analysis during fruit development

Sucrose content influences the flavour and quality of fruits. Sucrose synthase (SUS; EC 2.4.1.13) mediates the reversible conversion of uridine diphosphate and sucrose to uridine diphosphate-glucose and fructose. Although genome-wide analyses of SUS gene families exist for various species, such studies are lacking for pineapple. The specific SUS gene(s) involved in sucrose metabolism during pineapple development remain unknown. This study identified six SUS genes (AcSUS1-6) and analysed their chromosomal locations, synteny, structure, motif composition, sequence alignments, and phylogenetic relationships. Gene promoter analysis revealed a predominance of light-response elements in the AcSUS gene family. AcSUS1 was predominantly expressed in the peduncle, pericarp, and core, whereas AcSUS4 was highly expressed in the flesh. The levels of sucrose, glucose, and fructose increase during pineapple fruit development. Further gene expression analysis indicated that AcSUS2, AcSUS3, and AcSUS5 were down-regulated during this period. These results suggest that AcSUS2, AcSUS3, and AcSUS5 may modulate sucrose breakdown in pineapple. This study contributes to our understanding of SUS gene function in regulating sucrose metabolism and offers valuable theoretical guidance for the genetic improvement of pineapples.