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.

A Comparative Analysis of Allergen Proteins between Plants and Animals Using Several Computational Tools and Chou’s PseAAC Concept

“…Also, they found that the most numbers of predicted epitopes are dominantly located in the conserved sequences [52]. Furthermore, Chen et al [53] research on pollen allergens suggested that allergenic epitopes were located in conserved functional domains of proteins.…”

Search for New Allergens in Lolium perenne Pollen Growing under Different Air Pollution Conditions by Comparative Transcriptome Study

“…Nowadays, allergic diseases have become a pandemic health problem. Among them, pollen allergies are considered the most important [21]. Some studies showed that most of the patients sensitized to pollen allergens have perennial allergic rhinitis [21,22].…”

Comparative Proteomic Analysis of Mature Pollen in Triploid and Diploid Populus deltoides

“…Based on the genome-wide prediction, Chen et al predicted 145 and 107 pollen allergens from rice and Arabidopsis , respectively. These allergens are putatively involved in stress responses and metabolic processes such as cell wall metabolism during pollen development [ 40 ]. In the 28 candidate allergenic proteins from poplar mature pollen, several members belong to heat shock protein or profilin families.…”