Putative Allergens Identified in Mango (Mangifera indica Linn) Leaf and Fruit with Transcriptome Analysis

Abstract

Some allergens have previously been identified in mango (Mangifera indica Linn), including profilins, Bet v 1-like proteins and chitinase. In this paper, we identified the deepest investigation of mango potential allergens using high-throughput Illumina sequencing. RNA-Seq generated 11,751,123 contigs that were assembled into 99,328 unigenes with 16,848 unigenes of >1000 bp. A total of 230,242 unigenes were annotated using public protein databases, with a cut-off E-value above 10−5, of which 27,295, 46,030, 24,227 and 14,023 unigenes were assigned to gene ontology terms, Nr, Swiss-Prot and clusters of orthologous groups, respectively. A total of 66 potential allergen genes were identified, and their relative expressions were evaluated using Illumina RNA-Seq technology. Allergens mainly belonged to pollen allergen, pathogenesis-related protein Bet v I family and NADPH-dependent FMN reductase. We selected c61327.graph_c0, highly expressed in fruit and annotated as Pollen Ole e 1, was used as a template to obtain homologous protein structure in the RCSB PDB bank (PDB: 4z8w). We over-expressed and purified c61327.graph_c0, which could bind to human IgE by immunoblotting analysis. The epitope (74-SFRQEVKTEKHGEFKVHLPFSVSEHV-99) was speculated to confer allergic reactions. Therefore, this study provided a comprehensive systemic view of the transcriptome between mango leaf and fruit allergens endowed with biological activities, which will be useful for further genomic research studies and breeding of lower allergenic mango cultivars. Keywords: Mangifera indica Linn; transcriptome analysis; allergens; protein structure