Assembly of seed-associated microbial communities within and across successive plant generations

Abstract

Background and aims Seeds are involved in the transmission of microorganisms from one plant generation to another and consequently may act as the initial inoculum source for the plant microbiota. In this work, we assessed the structure and composition of the seed microbiota of radish (Raphanus sativus) across three successive plant generations.Methods Structure of seed microbial communities were estimated on individual plants through amplification and sequencing of genes that are markers of taxonomic diversity for bacteria (gyrB) and fungi (ITS1). The relative contribution of dispersal and ecological drift in inter-individual fluctuations were estimated with a neutral community model. Results Seed microbial communities of radish display a low heritability across plant generations. Fluctuations in microbial community profiles were related to changes in community membership and composition across plant generations, but also to variation between individual plants. Ecological drift was an important driver of the structure of seed bacterial communities, while dispersal was involved in the assembly of the fungal fraction of the seed microbiota. Conclusions These results provide a first glimpse of the governing processes driving the assembly of the seed microbiota.

Editorial special issue: the soil, the seed, the microbes and the plant

“…By analysing the community structure and diversity of endophytic bacteria within seeds, they provide strong evidence that the seed assemblages are similar across generations. However, Rezki et al (2018), using Raphanus sativus, show that across three generations, seed bacterial and fungal microbial communities display a low heritability, suggesting that ecological drift is an important driver of the structure of the seed bacterial communities but dispersal is involved in the assembly of seed fungal communities. Alibrandi et al (2018) characterize the seed endophytes of Anadenathera colubrina (Vell.)…”

Higher stochasticity of microbiota composition in seedlings of domesticated wheat compared to wild wheat

“…Most of the plant-associated microbiota is acquired from the environment, while a smaller component is vertically inherited e.g. via the seed (1), (2). Plant-microbe interactions range from parasitic or neutral to beneficial whereby the microbiota can contribute to increased nutrient uptake, stress tolerance and disease resistance (3), (4), (5).…”

“…For example, the model species Arabidopsis thaliana produces very small seeds that has limited detailed studies of the seedborne microbiota in this species (14). Thus, most studies of seedborne microbial communities have used culture dependent techniques or pooled multiple seeds for culture independent methods (2), (13), (15), (16), (17). While these studies have provided insight into overall diversity of seedborne microbiota, they have not allowed high-resolution analyses of microbial diversity within individual seeds, nor to which extent these microbial taxa co-evolve with the plant host.…”

The importance of phyllosphere on plant functional ecology: a phyllo trait manifesto

“…In this sense, experiments of cross-inoculation of phyllosphere core microbiomes (Ritpitakphong et al, 2016) between plants with different traits and strategies to detect the role of such interactions in the hierarchy of traits will be valuable. Moreover, phylogenetic tools will be important to describe whether phyllosphere traits may be 'heritable traits' in plant species or only dependent on horizontal transmission among species and individuals (Rodriguez, 2009;Partida-Mart ınez & Heil, 2015;Rezki et al, 2017). Therefore, the advancement of trait-based ecology depends on further comprehension of how plants and associated organisms inhabiting the phyllosphere (Friesen et al, 2011;Aguilar-Trigueros et al, 2017) and rhizosphere (Egamberdieva et al, 2017) respond to environmental drivers.…”