Genome-annotated bacterial collection of the barley rhizosphere microbiota

A culture collection of 41 bacteria isolated from the rhizosphere of cultivated barley (Hordeum vulgare subsp. vulgare) is available at the Division of Plant Sciences, University of Dundee (UK). The data include information on genes putatively implicated in nitrogen fixation, HCN channels, phosphate solubilization, and linked whole-genome sequences

Nitrogen fertilizers shape the composition and predicted functions of the microbiota of field-grown tomato plants

The microbial communities thriving at the root_soil interface have the potential to improve plant growth and sustainable crop production. Yet, how agricultural practices, such as the application of either mineral or organic nitrogen fertilizers, impact on the composition and functions of these communities remains to be fully elucidated. By deploying a two-pronged 16S rRNA gene sequencing and predictive metagenomics approach, we demonstrated that the bacterial microbiota of field-grown tomato (Solanum lycopersicum) plants is the product of a selective process that progressively differentiates between rhizosphere and root microhabitats. This process initiates as early as plants are in a nursery stage and it is then more marked at late developmental stages, in particular at harvest. This selection acts on both the bacterial relative abundances and phylogenetic assignments, with a bias for the enrichment of members of the phylum Actinobacteria in the root compartment. Digestate-based and mineral-based nitrogen fertilizers trigger a distinct bacterial enrichment in both rhizosphere and root microhabitats. This compositional diversification mirrors a predicted functional diversification of the root-inhabiting communities, manifested predominantly by the differential enrichment of genes associated to ABC transporters and the two-component system. Together, our data suggest that the microbiota thriving at the tomato root_soil interface is modulated by and in responses to the type of nitrogen fertilizer applied to the field

The fungal root endophyte Serendipita vermifera displays inter-kingdom synergistic beneficial effects with the microbiota in Arabidopsis thaliana and barley

Plant root-associated bacteria can confer protection against pathogen infection. By contrast, the beneficial effects of root endophytic fungi and their synergistic interactions with bacteria remain poorly defined. We demonstrate that the combined action of a fungal root endophyte from a widespread taxon with core bacterial microbiota members provides synergistic protection against an aggressive soil-borne pathogen in Arabidopsis thaliana and barley. We additionally reveal early inter-kingdom growth promotion benefits which are host and microbiota composition dependent. Using RNA-sequencing, we show that these beneficial activities are not associated with extensive host transcriptional reprogramming but rather with the modulation of expression of microbial effectors and carbohydrate-active enzymes

Genetics of Whole Plant Morphology and Architecture

Plant architectural features directly impact plant fitness and adaptation, and traits related to plant morphology and development represent important targets for crop breeding. Decades of mutagenesis research have provided a wealth of mutant resources, making barley (Hordeum vulgare L.) an interesting model for genetic dissection of grass morphology and architecture. Recent advances in genomics have propelled the identification of barley genes controlling different aspects of shoot and root development. In addition to gene discovery, it is important to understand the interplay between different developmental processes in order to support breeding of improved ideotypes for sustainable barley production under different climatic conditions. The purpose of the present chapter is to: (i) provide an overview of the morphology and development of shoot and root structures in barley; (ii) discuss novel insights into the genetic, molecular and hormonal mechanisms regulating root and shoot development and architecture; and (iii) highlight the genetic and physiological interactions among organs and traits with special focus on correlations between leaf and tiller development, flowering and tillering, as well as row-type and tillering