Meet the Winners of the 2020 Best Article Award From FEMS Microbiology Ecology
Dr Megan Morris (@meganmorris2187), Natalie Frixione, Alexander Burkert, Prof Elizabeth Dinsdale and Prof Rachel Vannette (@rachelvannette) from the University of California, Davis (USA) are the winners of the 2020 article award from FEMS Microbiology Ecology. Their winning paper is titled Microbial abundance, composition, and function in nectar are shaped by flower visitor identity.
We interviewed Megan, Natalie, Alexander, Elizabeth and Rachel to find out more about the paper and their answers can be found bellow.
Could you provide a brief, simple overview of the topic your paper covers?
In short, our manuscript examines the microbial ecology of a floral nectar system. For this particular system that we worked in, microbes (bacteria and fungi) are dispersal-limited and are primarily introduced into nectar via a vector, namely floral visitors and pollinators. The focal plant of this study system, Epilobium canum, or California fuchsia, attracts two primary floral visitors which contrast in their ecological services and foraging activity – one is a pollinating hummingbird (Anna’s hummingbird) which pollinates as it drinks nectar, and the second is a nectar-robbing carpenter bee that steals nectar resources without returning the service of pollination. We were curious if these two visitors, which have contrasting ecological roles, might also be affecting the system beyond what our eyes could see, via dispersal of unique microbial communities. In this study, which took place at the UC Davis Arboretum (Davis, CA, USA), we use both culture-dependent and -independent microbiological techniques to show that these two visitors, a pollinating hummingbird and nectar-robbing bee, deposit distinct microbial communities both in taxonomic composition and metabolic function, and that these divergent microbial communities have different capacities for metabolizing the nectar sugars.”
Why is it important for us to learn about how microbial abundance, composition, and function in nectar is shaped?
The microbial ecology of floral nectar is interesting for a few reasons. First, flowers are key for plant reproduction by mediating pollinator attraction and pollination, and nectar is a key reward for pollinators. So microbial communities in flowers can influence both plant reproduction and the actions and health of organisms that pollinate flowers. The microbial ecology of nectar has only recently been explored: it is a specialized environment with high osmotic stress where a few adapted microbial taxa survive. Second, microbes are dispersal-limited in this system due to the spatially discrete nature of individual flowers, and therefore rely on a vector, such as floral pollinators and visitors, for dispersal. But once introduced into nectar, adapted microbes can rapidly alter the nectar conditions by metabolizing compounds, such as polysaccharides, which modifies the chemical signature of nectar. We know from previous work that floral visitors which feed on nectar (e.g. pollinators such as hummingbirds and bees) have specific preferences for nectar chemical composition, and can be deterred by unpalatable nectar (see https://doi.org/10.1890/15-0858.1; https://doi.org/10.1111/nph.14809). Thus, microbial presence and metabolic activity can mediate plant-pollinator relationships, which are important to ecosystem functioning and agricultural health.”
What encouraged you to perform research in this area of microbiology?
The Vannette Lab has been working on both applied science and basic research revolving around plant-pollinator-microbial relationships since its inception in 2015. The lead author on the paper, Megan Morris, designed this experiment with Rachel Vannette while she was a visiting PhD student at UC Davis. Both researchers were interested in how microbes mediate multitrophic interactions and participate in ecosystem functioning, as microbes have traditionally been overlooked in ecological studies. While microbes are ubiquitous in the environment, we are only recently understanding the scope and magnitude of their importance in ecological interactions, such as plant-pollinator relationships. We now have the advantage of newer sequencing technology and bioinformatics approaches, so we could collaborate with author Elizabeth Dinsdale to incorporate a metagenomics approach to more fully describe the ecological function of nectar-associated microbial communities.”
What do you see as the next steps in this area of research?
First, we think that it will be promising to investigate the ecology and metabolic potential of flower-dwelling bacteria and yeasts: how do they disperse among flowers? What resources are they using in flowers and how do they affect plant reproduction? Why do we see host specialization among species and strains of flower-inhabiting bacteria?
Second, how do floral bacteria and yeasts affect pollinators, including bees, butterflies, birds and other organisms that visit nectar? Do these microbes affect pollinator nutrition or physiology? To what degree do microbes rely on specific pollinator species for dispersal?”
This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
Read the 2020 award winning paper: Microbial abundance, composition, and function in nectar are shaped by flower visitor identity