Unrevealing the role of plant growth-promoting bacteria in recruiting microbiome from maize rizosphere

Abstract

The beneficial plant-microbes association have been widely explored with the purpose of understanding the mechanisms involved in this interaction, in order to develop bioinoculants for agriculture aiming at sustainability and reduction of chemical inputs use. Plant Growth Promoting Bacteria (PGPBs) have been reported as interesting alternatives to mineral fertilizers for a range of crops. The strain Bacillus sp. RZ2MS9 and the genus Azospirillum have shown potential in plant growth promotion, and for that they are called PGPBs. However, the lack of holistic comprehension about PGPBs-plant-native soil microbiota can lead to inconsistency of results in field conditions. Recent ecological theories reveal that plant microbiomes are organized as microbial hubs with keystone species and helpers. These microbial networks are strongly connected, molecularly modulated and can influence plant metabolism and physiology. The molecular modulation of such association can be accessed with the advance of high throughput sequencing and phenotyping technologies. It has been possible to access information about the plant-associated bacterial community (including those non-cultivable), correlate it with the main microbiota-modulating factors, such as plant genotype, growth stage and physiological responses under influence of biostimulants. Thus, through metagenomics, metatranscriptomics, metaproteomics and phenomics, the objective of this project is to characterize the microbial community associated with 3 maize genotypes under influence of the potential keystone PGPBs Bacillus sp. RZ2MS9 and A. brasilense Ab-v5 to support the original development of a synthetic minimum microbiome including these two species as keystones for plant growth promotion, aiming at the construction of a bacterial consortium. This unprecedent omics approach for the holistic view of the complex system composed by inoculant-plant-microbiota and data integration will allow the development of new strategies for optimization of plant biostimulats recommendation with enhanced efficiency for establishment in the field. (AU)