The bacterial microbiota of a parasitic plant and its host

Abstract

2How plant-associated microbiota are shaped by, and potentially contribute to the unique 3 ecology and heterotrophic life history of parasitic plants is relatively unknown. Here, we 4 investigate the leaf and root bacterial communities associated with the root holoparasite 5Orobanche hederae and its host plant Hedera spp. We sequenced the V4 region of the 6 16S rRNA gene from DNA extracted from leaf and root samples of naturally growing 7 populations of Orobanche and infected and uninfected Hedera. Root bacteria inhabiting 8Orobanche were less diverse, had fewer co-associations, and displayed increased 9 compositional similarity to leaf bacteria relative to Hedera. Overall, Orobanche bacteria 10 exhibited significant congruency with Hedera root bacteria across sites, but not the 11 surrounding soil. Infection had localized and systemic effects on Hedera bacteria, which 12 included effects on the abundance of individual taxa and root network properties. 13Collectively, our results indicate that the parasitic plant microbiome is derived but distinct 14 from host plant microbiota, exhibits increased homogenization between shoot and root 15 tissues, and displays far fewer co-associations among individual bacterial members. 16Host plant infection is accompanied by modest changes of associated microbiota at both 17 local and systemic scales compared with uninfected individuals. Our results provide 18 insight into the assembly and function of plant microbiota. 19