Climate Change Impacts on Broussenetia papyrifera Pollens - Metabolome Investigations and Prospects of Allergy Prevalence
Broussonetia papyrifera (B. papyrifera) is an allergenic plant in the mulberry family that grows at varied elevations and climatic conditions worldwide. In northern Pakistan, B. papyrifera is abundant and it produces a substantial amount of pollen that disperses in the air causing allergies in some humans. Climate change affects pollen production. To investigate potential changes in pollens development and potential allergenicity, B. papyrifera pollens were collected in summer and in spring from different regions in Pakistan. Study samples were subjected to morphological analysis, Fourier Transform Infrared Spectroscopy (FTIR) analysis for biochemical differences, and Liquid Chromatography-Mass Spectrometry (LCMS) for metabolome analysis. Morphological studies of the dried pollen by light microscopy showed seasonal and regional differences in pollens size and exine morphology. FTIR analysis showed inter-regional and inter-seasonal differences in the metabolome of the pollen. Differences in lipid and protein functional groups of pollen from different regions showed variation in the FTIR spectra. These differences in FTIR spectra correlated with the changing climatic conditions. Metabolome analysis of targeted pollen samples identified 33 organic compounds of seven different groups. Four unsaturated fatty acids were identified that have a potential role in allergic responses. The findings in this study are unique in demonstrating climatic variables that effect B. papyrifera pollen physiology (FTIR analysis) which also confirms differences in pollen-associated lipid metabolites identified by LCMS analysis. These results demonstrate information that may be used to predict potential changes in allergy risks from pollens of B. papyrifera in the future. The findings may provide a model for predicting variation in pollen structure and associated allergies in response to climate changes for other species.