Broussonetia papyrifera Pollen Metabolome Insights, Allergenicity, and Dispersal in Response to Climate Change Variables

<b>Background/Objectives</b>: <i>Broussonetia papyrifera</i> is a tree-producing allergenic pollen that grows in varied climatic conditions worldwide and causes pollen allergies in susceptible humans. This study aimed to investigate <i>B. papyrifera</i> pollen morphology, pollen metabolome, pollen allergenicity, and climate change's impact on the plant habitat suitability in the future. <b>Methods</b>: Tree pollen was collected in spring from different regions of Pakistan. Pollen samples were subjected to morphological analysis, Fourier transform infrared spectroscopy (FTIR), liquid chromatography-mass spectrometry (LC-MS/MS), and immunoblotting. <b>Results</b>: MaxEnt modeling predicted the tree's future-growth invasion into new regions. Scanning electron microscopy (SEM) and FTIR displayed regional differences in pollen morphology and metabolome correlated to shifts in climatic variables. LC-MS/MS analysis detected four lipids that can potentially stimulate inflammatory responses. Pollen protein immunoblotting studies identified a putative 15 kDa novel allergen and verified previously known 40 kDa, 33 kDa, and 10 kDa allergens. <i>B. papyrifera</i> MaxEnt modeling through ACCESS1.0 and CCSM4 under 2-greenhouse gas emissions scenarios {representative concentration pathway (RCP) 4.5 and 8.5} projected the tree invasion by the years 2050 and 2070. <b>Conclusions</b>: The study findings demonstrate that differences in climatic variables affect <i>B. papyrifera</i>-pollen metabolome and predict the habitat suitability of the tree for invasion in the future. The study results provide a model system for studying other species' pollen morphology, metabolome, future habitat suitability for plant invasion, and associated allergies in response to climate change.