Speaker
Description
The phyllosphere of temperate trees is a dynamic environment and undergoes phenological changes throughout the growing season. However, the key drivers of phyllosphere microbiome dynamics are still poorly understood. Following bacterial community composition and throughfall-mediated bacterial transport for oak (Quercus robur L.), ash (Fraxinus excelsior L.) and linden (Tilia cordata MILL) across early (May), mid (July) and late (October) phenological stages, we hypothesized that phenology-driven changes will have a stronger effect on phyllosphere bacterial communities than tree species identity, and that throughfall-mediated transport of bacteria will shape distribution patterns within the canopy. We collected leaves and throughfall samples at the top, middle, and bottom canopy positions at the Leipzig canopy crane facility (Germany). Phyllosphere bacterial community assembly was mostly driven by dispersal limitation at the early phenological stage while communities became more homogeneous and functionally redundant during mid–late phenological stages. During the early phenological stage, early-colonisers such as Erwiniaceae possibly occupied niches through priority effects, while later new bacterial taxa got introduced at mid–phenological stages and shared the niches with successional bacteria. The strong decline of potential plant pathogens towards the late phenological stage may be attributed to plant defense or microbially mediated biocontrol mechanisms, evident from a higher enrichment of steroid and polyketide synthase pathways in the communities’ functional potential. Throughfall-mediated transport of bacteria increased substantially from March to May, indicating the strong influence of wash-off effects from the emerging foliage on the transported communities. Patterns of preferential attachment to leaves and mobilization by throughfall appeared to be taxon-specific across different canopy positions. Our findings demonstrate that in temperate forests, phenology-driven effects on the phyllosphere microbiome are far more important than tree species’ specific effects. Selectivity of throughfall-mediated mobilization and detachment may play an important role for the spatial heterogeneity of microbial communities in tree crowns.
Key words: Phyllosphere; throughfall; temperate forest; drift and dispersal limitation
| Status Group | Postdoctoral Researcher |
|---|---|
| Poster Presentation Option | Yes, I’m willing to present as a poster. |
