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 <i>SUS</i> gene families exist for various species, such studies are lacking for pineapple. The specific <i>SUS</i> gene(s) involved in sucrose metabolism during pineapple development remain unknown. This study identified six <i>SUS</i> genes (<i>AcSUS1–6</i>) 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 <i>AcSUS</i> gene family. <i>AcSUS1</i> was predominantly expressed in the peduncle, pericarp, and core, whereas <i>AcSUS4</i> was highly expressed in the flesh. The levels of sucrose, glucose, and fructose increase during pineapple fruit development. Further gene expression analysis indicated that <i>AcSUS2</i>, <i>AcSUS3</i>, and <i>AcSUS5</i> were down-regulated during this period. These results suggest that <i>AcSUS2</i>, <i>AcSUS3</i>, and <i>AcSUS5</i> may modulate sucrose breakdown in pineapple. This study contributes to our understanding of <i>SUS</i> gene function in regulating sucrose metabolism and offers valuable theoretical guidance for the genetic improvement of pineapples.