DEVELOPMENT OF AN ANALYTICAL APPROACH TO IDENTIFY NETWORKS IN THE RHIZOSPHERE MICROBIOME

Abstract

Phosphorus is the least mobile macronutrient and about 30% of the soils around the globe show high potential to fixate phosphates making it less available for plant uptake. Modern cultivars generally are not highly efficient in phosphate acquisition and utilization as they have been selected in high input environments. Rhizosphere microbiome has a potential important role in the phosphorus supply to the plants, both facilitating the acquisition and mobilizing fixed phosphate. In my ongoing project, we proposed the hypothesis that inefficient cultivars in phosphorus uptake growing in phosphorus limiting conditions and using less soluble source of phosphorus will enrich the rhizosphere microbiome with phosphorus mobilizing microorganisms. Rhizosphere community structure was assessed through 16S rRNA gene parallel amplicon sequencing. The diversity and community structure was assessed through initial exploratory multivariate analysis. In order to develop a consistent statistical pipeline congruent with the integration in the "Back to the Roots" initiative, we propose the application of a pipeline already developed for microbiome analysis. Given the complexity of the dataset, the proposed analytical workflow that includes: constrained ordination according to ecological variables and differential analysis of fold change in count data to improve interpretability of estimates. We also propose to develop a network analysis, that can identify direct and indirect interactions among community members and the nature of these associations in response to phosphorus levels. Through these analysis, we intend to identify factors (cultivars contrasting in P-uptake efficiency, phosphorus doses and sources) with higher influence in rhizosphere community structure and establish a standard pipeline for microbiome analysis.