The seeds of Plantago lanceolata comprise a stable core microbiome along a plant richness gradient.

Introduction

Research has demonstrated the critical role of diversity in ensuring the stability and resilience of a community in the face of environmental disturbances. This stability may be achieved through increasing metabolic complementarity and redundancy, which ensures the smooth functioning of different physiological processes at different trophic levels.

Goals

We investigated the effects of biodiversity on the diversity and composition of the microbiome of P. lanceolata seed, addressing the question whether the species richness of the surrounding plant community can influence the recruitment of bacteria from the parental plant to its seeds.

Materials and Methods

To access the effects of increasing biodiversity we made use of a well-established biodiversity experiment, The Jena Experiment (https://the-jena-experiment.de/), established on the floodplain of the Saale River, in Jena, Germany. There, biodiversity is manipulated in the form of a plant species richness gradient ranging from monoculture to 60 species. We sampled blossoms from P. lanceolata individuals grown on plots with different plant richness (monoculture, 4, 8 and 16 species). Seeds were surface sterilized to remove seed associated microbes and DNA extraction was performed. Metabarcoding and NGS sequencing was used to assess bacterial diversity in the seed materials.

Results

Our data identified that endophytic microbiome composition of P. lanceolata seeds comprises a rather stable core microbiome, consisting of Pseudomonas rhizosphere, Sphingomonas faeni and Pirellula spp. However, we also identified unique taxa that only occur at certain diversity levels, such as Pedobacter spp. which was exclusively found on the plots with 4 species richness. Furthermore, we found the number of unique Amplicon Sequence Variants increase with plant diversity.

Summary

Our study nicely demonstrates that despite a rather stable core microbiome along the plant diversity gradient, plant diversity had an influence on the structure of the seed microbiome of P. lanceoata. The data has being acepted for publication in the Envriomental Microbiome Journal in January/2024.