Phleum pratense-pollen adaptive variations and pollen microbiome investigation under different climatic regions and prospects of allergenicity

Abstract

Abstract Phleum pratense is an allergenic grass that pollinates in spring. Databases Allergenonline.org and Allergen.org record ten P. pratense allergens and their isoforms. Phl P 1, Phlp 5 and Phl p 11 are major P. pratense-pollen allergens with demonstrated basophil activity and skin test reactivity. Little is known about P. pratense pollen adaptive variations in different climatic regions and pollen associated microbial diversity. In this study, we collected P. pratense-pollens in the spring season 2022, from three climatic regions (R1, R2 and R3) in Pakistan having difference in mean annual air temperature, mean annual precipitation and elevation. The morphology of pollens was observed by light microscopy, scanning electron microscopy (SEM), biochemical fingerprint analysis and composition of pollens were investigated by fourier-transform infrared spectroscopy (FTIR). The pollen-associated bacterium was identified through Biolog GEN III microplate system. The pollen water-soluble proteins were isolated and stabilized in phosphate buffer saline (PBS) and tested for allergenicity response through dot blots and western blots analysis. Morphological study found difference in pollen biochemical composition. Biolog identified Brevibacterium epidermidis from P. pratense pollens. Protein extracts quantification and sodium dodecyl sulfate-poly acrylamide gel electrophoresis (SDS-PAGE) gel found decreased protein expression in R1 region pollens in comparison to R2 and R3 regions pollens. Allergenicity studies found differential expression of beta-expansin and profilin (allergens) in pollens obtained from three regions. Beta-expansin and profilin were suppressed in R1 pollens, and expressed in R2 and R3 pollens. This is the first study to identify B. epidermidis growth on P. pratense pollen. A variable allergen expression in P. pratense pollens has also been observed in different regions. An increase in mean annual temperature and decrease in mean annual precipitation affected pollen biochemical composition, and inhibited beta-expansin and profilin expression involved in pollen growth and development. Therefore, the findings of the research are unique, which enhances basic knowledge and understanding of P. pratense-pollen associated microbiota and climate change impacts on the pollen allergen expression.