Characterization of MiFUT11 from Mangifera indica L.: A functional core α1, 3-fucosyltransferase potentially involved in the biosynthesis of immunogenic carbohydrates in mango fruit

In- higher plants, asparagine-linked oligosaccharides (N-glycans) in glycoproteins carry unique carbohydrate epitopes, namely, a core alpha 1,3-fucose and/or a beta 1,2-xylose, which are common determinants responsible for the cross-reactivity of plant glycoproteins due to their strong immunogenicity. While these determinants and the relevant genes have been well characterized for herbaceous plants, information concerning whether many food plants cross-react with airborne pollens is not available. In this paper, we report on the characterization of a novel core alpha 1,3-fucosyltransferase gene identified from Mangifera indica L., one of the major plants potentially related to food allergy. Based on sequence information of plant homologues, we amplified a candidate cDNA (MiFUT11) from pericarp tissue. An in vitro assay demonstrated that the recombinant MiFUT11 protein transfers a fucose unit onto both non-fucosylated and core alpha 1,6-fucosylated oligosaccharides. A glycoform analysis using MALDI-TOF mass spectrometry showed that the introduction of the MiFUT11 cDNA increased the production of a core alpha 1,3- and alpha 1,6-fucosylated pauci-mannosidic oligosaccharide in Spodoptera Sf21 cells. Our findings suggest that MiFUT11 is a functional core alpha 1,3-fucosyltransferase gene that is involved in the assembly of cross-reactive N-glycans in mango fruit.