STRATEGIES AND MECHANISMS OF PLANT-MICROBIOME-POLLINATOR COADAPTATION

Plant-pollinator interactions showcase mutualistic coevolution, but the role of microorganisms in these relationships is often overlooked. Nectar-dwelling microorganisms, mainly yeasts and bacteria, significantly influence floral chemistry, pollinator behavior, and plant reproduction. These microorganisms alter nectar’s sugar content, amino acid profiles, pH, and scent emissions, shaping pollinator preferences. For example, the yeast Metschnikowia reukaufii produces fruity esters that attract bumble bees, while some bacteria lower pH, repelling honey bees. Pollinators spread these microorganisms between flowers, creating a feedback loop that shapes microbial communities and drives coevolution. Beyond nectar, microorganisms' impact on thermal regulation through metabolic heat, pollen health, and pollinator gut microbiomes. Specialized bacteria like Rosenbergiella nectarea and Acinetobacter spp. thrive in nectar’s high-sugar environment, while pollinator microorganisms, such as Lactobacillus kunkeei, protect honey bees from pathogens. Microbial diversity varies by region, with tropical flowers hosting richer communities than temperate ones. This review highlights how microorganisms act as key players in plant-pollinator networks, boosting pollinator nutrition, immunity, and foraging efficiency. It explores microbial spread, competition, and chemical influence, calling for studies that blend microbiology, ecology, and evolution. Understanding these interactions is vital for predicting how climate change and habitat loss threaten pollination, affecting agriculture and biodiversity.