PLANTHOLOGENOME · The plant hologenome – is plant adaptative potential shaped by its microbionts?

Explaining why related species have very different abilities to spread, adapt and survive is a central question in evolutionary biology. Microbes have long been recognized as key to the ability of plants or animals to explore resources in their environment, and there is now growing recognition that microbionts should be considered an integral part of their host. The holobiont theory state that a plant or animal cannot be considered as an individual organism, but as a holobiont consisting of the host and the sum of all its microbionts, and that adaptive genomic changes in the holobiont also includes changes in its microbiont community. The range of microbionts a species is able to associate with through time and space has been suggested to be correlated to host adaptability to different environments and could thus be an important component in distribution patterns in plants. In this project, I aim to establish the association between wild plant genomes, their microbiont communities and their habitat use, using orchids and their associated microbiomes as a model system. I will generate bacterial and fungal metagenomic profiles from tissue samples from orchids and couple it with host genomic variation to i) Explore the link between individual plant genotype and microbiont community profile using individual level sampling from two closely related orchid species, ii) Measure differences in range and variability of microbiont community among 20 congeneric wild orchid species, and iii) Correlate species-level diversity and variability of microbiont community with distribution range and habitat diversity in 20 congeneric orchid species. The results will impact our general understanding of the importance of plant microbiomes in determining their adaptive and evolutionary success, and provide important knowledge on factors effecting plant distribution of high relevance in nature management and conservation of threatened plant species.