Analysis of root development and architecture of tropical pastures inoculated with Azospirillum brasilense and Pseudomonas fluorescens to build drought resistant materials using WUR-NPEC G4 rhizotron, The Netherlands

Abstract

This SPRINT proposal will contribute to the ongoing research project funded by FAPESP entitled "Physiological and productive performance of forages Brachiaria brizantha cv Marandu and the hybrid Brachiaria Mavuno inoculated with Azospirillum brasilense and subjected to warming in a future climate simulation" (Process 2022/15021-2) coordinated by Carlos Alberto Martinez y Huaman. In this project we are studying the effects of warming - an increase in plant temperature by +2°C using the Temperature free-air controlled enhancement (T-FACE), in a future climate simulation experiment - and of inoculation with two strains of nitrogen-fixing bacteria: Azospirrillum brasilense: CNPSo 2083 and CNPSo 2084, and Pseudomonas fluorescens developed by EMBRAPA, on the physiological and productive performance of two forage types of grass: Brachiaria brizantha cv Marandu and the hybrid Brachiaria brizantha x Brachiaria ruziziensis, called Mavuno. Physiological, nutritional, biochemical, growth, plant productivity, and forage quality parameters are being evaluated. We hypothesize that Brachiaria plants inoculated with N-fixing bacteria present a better physiological and productive performance than non-inoculated plants, during all-year seasons, including under high temperatures in dry and wet seasons. The proposed hypothesis is plausible because there is strong evidence that in inoculated grasses, in addition to fixing the N from the air, the plant growth-promoting bacteria (PGPB) as Azospirillum and Pseudomonas bacteria also stimulate root growth, maintaining plant productivity, even in conditions of scarce water availability. Root development is critical for plant growth and therefore a crucial factor in plant performance and food production. Plant root architecture plasticity and root development in response to inoculation with PGPB have not been thoroughly investigated. The importance of plant roots has been increasingly highlighted, particularly under new global climate change scenarios, with increasing periods of drought, higher temperatures, and fertilizer crises with a scarcity of nutrients. In the SPRINT research project, we will study the plant root development and architecture of the tropical grasses B. brizantha cv Marandu and the hybrid Mavuno inoculated with two nitrogen-fixing bacteria: Azospirrillum brasilense and Pseudomonas fluorescens, by effect of environmental variables as soil temperature and soil water content, using the Netherlands Plant Eco-phenotyping Centre (NPEC) G4 rhizotron facility. In this study, the NPEC platform will provide high-throughput plant phenotyping conditions. The rhizotron technology at NPEC will allow us to study root development and root architecture at a scale and level of precision that would not be possible to do with traditional methods. The SPRINT project is a collaboration between The Wageningen University and Research (WUR), The Netherlands Plant Eco-phenotyping Centre (NPEC) (www.NPEC.nl) with The University of São Paulo (USP). (AU)