The successful history of A. brasilense Az39 in Agriculture. A metadata analysis.

BELEN RODRIGUEZ; SOFIA NIEVAS; GASTON LOPEZ; ROMINA MOLINA; ANAHÍ CONIGLIO; VERÓNICA MORA; FABRICIO CASSÁN

Simposio; MICROBE-ASSISTED CROP PRODUCTION 2019 OPPORTUNITIES, CHALLENGES & NEEDS; 2019

Azospirillum is one of the most studied bacterial genera in the last 60 years; However, the history of the appearance ofbiological products formulated with this bacterium began in the 1980s, but intensified in the last 20 years in Argentina,Brazil and the rest of South America. In the case of Argentina, A. brasilense Az39 is the strain that has beenrecommended for more than 40 years for the production of biofertilizers for wheat, sorghum, corn and soybean (coinoculation). This strain has demonstrated a great capacity to promote plant growth with average yield increases greaterthan 10.0% and a success rate higher than 70% in different crops in thousand experiments. Despite the immense amountof information available at the agronomic level, until a few years ago very little was known about the molecular basisthat determined the ability of this strain to promote plant growth. In 2012, the Laboratorio de Fisiología Vegetal y de laInteracción Planta-Microorganismo of the Universidad Nacional de Río Cuarto conformed an international consortiumwith the aim to analyze the genome sequence of A. brasilense Az39 and B. japonicum E109, two of the most used strainsfor biofertilizer production in South America. Using a combined sequencing strategy, it was established that the Az39genome has a size of 7.39 Mpb distributed in 6 replicons [1 chromosome, 3 chromides and 2 plasmids]. Through the useof comparative bioinformatics tools, numerous genes and putative proteins involved in the expression of plant growthpromotion mechanisms and other related with the rhizosphere lifestyle were identified. The decoding of thisinformation has provided a solid basis for the elucidation of new mechanisms of interaction and growth promotion, aswell as some specific components that would determine the agronomic success of this microorganism. In thispresentation we will address some of the new biological models recently identified for this bacterium and how theyaffect their rhizosphere lifestyle