title: Origin and Functional Prediction of Pollen Allergens in Plants.
abstract: Pollen allergies have long been a major pandemic health problem for human. However, the evolutionary events and biological function of pollen allergens in plants remain largely unknown. Here, we report the genome-wide prediction of pollen allergens and their biological function in the dicotyledonous model plant Arabidopsis (Arabidopsis thaliana) and the monocotyledonous model plant rice (Oryza sativa). In total, 145 and 107 pollen allergens were predicted from rice and Arabidopsis, respectively. These pollen allergens are putatively involved in stress responses and metabolic processes such as cell wall metabolism during pollen development. Interestingly, these putative pollen allergen genes were derived from large gene families and became diversified during evolution. Sequence analysis across 25 plant species from green alga to angiosperms suggest that about 40% of putative pollen allergenic proteins existed in both lower and higher plants, while other allergens emerged during evolution. Although a high proportion of gene duplication has been observed among allergen-coding genes, our data show that these genes might have undergone purifying selection during evolution. We also observed that epitopes of an allergen might have a biological function, as revealed by comprehensive analysis of two known allergens, expansin and profilin. This implies a crucial role of conserved amino acid residues in both in planta biological function and allergenicity. Finally, a model explaining how pollen allergens were generated and maintained in plants is proposed. Prediction and systematic analysis of pollen allergens in model plants suggest that pollen allergens were evolved by gene duplication and then functional specification. This study provides insight into the phylogenetic and evolutionary scenario of pollen allergens that will be helpful to future characterization and epitope screening of pollen allergens.
authors.affiliation: Joint International Research Laboratory of Metabolic and Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China (M.C., J.X., J.S., K.R., D.Z.);School of Agriculture, Food, and Wine, University of Adelaide, Waite Campus, Urrbrae, South Australia 5064, Australia (D.D., I.S., D.Z.); andSchool of Biological Sciences, University of Adelaide, South Australia 5005, Australia (I.S.).
authors.forename: Miaolin
authors.initials: M
authors.lastname: Chen
authors.affiliation: Joint International Research Laboratory of Metabolic and Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China (M.C., J.X., J.S., K.R., D.Z.);School of Agriculture, Food, and Wine, University of Adelaide, Waite Campus, Urrbrae, South Australia 5064, Australia (D.D., I.S., D.Z.); andSchool of Biological Sciences, University of Adelaide, South Australia 5005, Australia (I.S.).
authors.forename: Jie
authors.initials: J
authors.lastname: Xu
authors.affiliation: Joint International Research Laboratory of Metabolic and Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China (M.C., J.X., J.S., K.R., D.Z.);School of Agriculture, Food, and Wine, University of Adelaide, Waite Campus, Urrbrae, South Australia 5064, Australia (D.D., I.S., D.Z.); andSchool of Biological Sciences, University of Adelaide, South Australia 5005, Australia (I.S.).
authors.forename: Deborah
authors.identifier: 0000-0002-6050-9947
authors.initials: D
authors.lastname: Devis
authors.affiliation: Joint International Research Laboratory of Metabolic and Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China (M.C., J.X., J.S., K.R., D.Z.);School of Agriculture, Food, and Wine, University of Adelaide, Waite Campus, Urrbrae, South Australia 5064, Australia (D.D., I.S., D.Z.); andSchool of Biological Sciences, University of Adelaide, South Australia 5005, Australia (I.S.).
authors.forename: Jianxin
authors.identifier: 0000-0002-7717-0863
authors.initials: J
authors.lastname: Shi
authors.affiliation: Joint International Research Laboratory of Metabolic and Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China (M.C., J.X., J.S., K.R., D.Z.);School of Agriculture, Food, and Wine, University of Adelaide, Waite Campus, Urrbrae, South Australia 5064, Australia (D.D., I.S., D.Z.); andSchool of Biological Sciences, University of Adelaide, South Australia 5005, Australia (I.S.).
authors.forename: Kang
authors.initials: K
authors.lastname: Ren
authors.affiliation: Joint International Research Laboratory of Metabolic and Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China (M.C., J.X., J.S., K.R., D.Z.);School of Agriculture, Food, and Wine, University of Adelaide, Waite Campus, Urrbrae, South Australia 5064, Australia (D.D., I.S., D.Z.); andSchool of Biological Sciences, University of Adelaide, South Australia 5005, Australia (I.S.).
authors.forename: Iain
authors.initials: I
authors.lastname: Searle
authors.affiliation: Joint International Research Laboratory of Metabolic and Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China (M.C., J.X., J.S., K.R., D.Z.);School of Agriculture, Food, and Wine, University of Adelaide, Waite Campus, Urrbrae, South Australia 5064, Australia (D.D., I.S., D.Z.); andSchool of Biological Sciences, University of Adelaide, South Australia 5005, Australia (I.S.) zhangdb@sjtu.edu.cn.
authors.forename: Dabing
authors.identifier: 0000-0002-1764-2929
authors.initials: D
authors.lastname: Zhang
mesh_terms: D000485:Allergens / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D016000:Cluster Analysis; D020869:Gene Expression Profiling / Q000379:methods; D018506:Gene Expression Regulation, Plant; D063990:Gene Ontology; D018745:Genome, Plant / Q000235:genetics; D006801:Humans; D012275:Oryza / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D010940:Plant Proteins / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D010944:Plants / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D011058:Pollen / Q000235:genetics* / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
chemical_list: D000485:Allergens; D010940:Plant Proteins