Genus Azospirillum is one of the plant growth promoting rhizobacteria (PGPR) best studied and most used for the agricultural production. Although more than 20 species have been described within the genus at present (DSMZ 2018, Bashan and De-Bashan, 2010, Hungary et al, 2010, 2011, Fukami et al., 2016, Peret et al., 2016), A. brasilense and A. lipoferum are the best characterized both biochemically and genetically (Baldani and Baldani 2005, Fibach-Paldi et al., 2012) and the most widely used in commercial inoculants.This microorganism colonize more than one hundred plant species and exist abundant information about the improve in growth, development and production in field conditions (Bashan and de-Bashan, 2010; Cassan and Diaz-Zorita, 2016). Although early studies regarding the effects of Azospirillum to induce plant growth were mainly associated with the capacity to fix N2, today it is known that the bacterium has different additional mechanisms that contribute to greater growth and crop yield. Bashan and De-Bashan (2010) proposed the ?theory of multiple mechanisms? in which the bacterium in its interaction with the plant and the environment deploys a series of mechanisms in a simultaneous or consecutive manner, in which general and/or specific patterns of each particular interaction are generated. Among the other addicionaly mechanisms that contribute to the promoting plant growth, the phosphate solubilization, phytohormone and/or siderophore production (Puente et al., 2004), phytopathogens control (Bashan and de-Bashan, 2010) and protection against abiotic stress like drought, salinity or toxic compounds (Creus et al., 1997), have been characterized.

Fil: Filippone, María Paula. Universidad Nacional de Tucuman. Facultad de Agronomia y Zootecnia. Departamento de Ecología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Tecnología Agroindustrial del Noroeste Argentino. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (p). Instituto de Tecnología Agroindustrial del Noroeste Argentino; Argentina

Fil: Pedraza, Raúl Osvaldo. Universidad Nacional de Tucuman. Facultad de Agronomia y Zootecnia. Departamento de Ecología; Argentina

Fil: Fontana, María Cecilia. Instituto Nacional de Tecnología Agropecuaria; Argentina

Fil: Ramirez Mata, Alberto. Benemérita Universidad Autónoma de Puebla; México

Fil: Sierra Cacho, Daniela. Benemérita Universidad Autónoma de Puebla; México

Fil: Salazar, S.. Instituto Nacional de Tecnología Agropecuaria; Argentina

Fil: Baca, Beatriz. Benemérita Universidad Autónoma de Puebla; México