Mitigation of water stress in maize (Zea mays L.) after arbuscular mycorrhizal fungi and growth promoting rhizobacteria inoculation

Abstract

Water is essential for the microbial metabolism in the terrestrial ecosystem but recent global events have caused irregularities in its distribution. Long dry periods have increased losses in maize productivity, especially when the water deficit coincides with critical stages of the plant's development. Thus, one of the scientific challenges is to find biotechnological strategies that minimize water stress in maize and thereby meet the food and energy demand. We will use Arbuscular Mycorrhizal Fungi (AMF) and drought-tolerant rhizobacteria inoculation, isolated from an environment with high water restriction (Caatinga Biome), in the maize culture. AMF and rhizobacteria will be isolated from the rhizospheric soil samples of Tripogon spicatus (Nees) plants, known as "resurrection plants", due to their extraordinary rehydration capacity. AMF spore propagation will be with trap cultures under different water regimes in the substrate, corresponding to 80%, 50% and 30% of the field capacity, using maize plants as bait. After isolation of AMF and rhizobacteria isolates, we will set up a greenhouse experiment using, in consortium or not, AMF and rhizobacteria. We will evaluate vegetative and physiological attributes of plants and soil, such as dry matter, nutrient contents, enzymatic activity in soil and plant, soil glomalin content, besides community structure of mycorrhizal fungi and soil bacteria. We will integrate all the data obtained in multivariate models in order to obtain the feedback of the soil-plant-micro-organisms sets. We hope to fill the gap of knowledge existent regarding AMF inoculation, alone or in conjunction with drought tolerant rhizobacteria on maize crop for the mitigation of soil water stress. (AU)