Speakers
- Prof. Marco Giovannetti — University of Turin
- Valeriana Ramondo — Springer Nature (Italy)
- Eleana Pegg — Springer Nature (United Kingdom)
Abstract
Lettuce leaves aren't just a salad ingredient — they're a habitat. This talk presents recent research showing that a lettuce plant's own form, more than its genetics, shapes the bacterial community living on its leaves. Analyzing 131 fully-sequenced lettuce genotypes, the study found that breeder-defined variety and specific leaf traits — heart formation, head height, and vein pattern — explained more of the variation in leaf bacteria than raw genetic distance or leaf nutrient content did. Together, plant-related factors accounted for about 13% of the differences observed in leaf bacterial diversity, with morphology (especially how tightly a lettuce head forms and how far its leaves sit from the soil) playing the largest role. This "edible microbiome" matters because some of these leaf bacteria are shared with — and can influence — the human gut microbiome.
The talk then connects this research to Citizen Salad (citizensalad.unito.it), a participatory science project that puts these same questions in the hands of the public. Funded through a crowdfunding campaign that engaged 144 backers, the project recruited over 100 citizen-experimenters across 16 Italian provinces, each growing two lettuce varieties in their own garden. Leaves and soil are now being analyzed for DNA to ask three parallel questions: which bacteria live on the leaves, whether different lettuce varieties host different bacterial communities, and where those bacteria come from (seed, soil, or air) — turning members of the public into direct contributors to phyllosphere microbiome research.
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