Pseudomonas stutzeri MJL19, a rhizosphere‐colonizing bacterium that promotes plant growth under saline stress

LAMI, MARÍA JESÚS; ADLER, CONRADO; CARAM?DI SANTO, MARÍA CAROLINA; ZENOFF, ANA MARÍA; DE CRISTÓBAL, RICARDO E.; ESPINOSA?URGEL, MANUEL; VINCENT, PAULA A.

JOURNAL OF APPLIED MICROBIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2020

1364-5072

ABSTRACTAims: The aim of this study was to find and use rhizobacteria able to confer plants advantages todeal with saline conditions.Methods and Results: We isolated 24 different bacterial species from the rhizosphere ofhalophyte plants growing in Santiago del Estero, Argentina salt flat. Four strains were selected upontheir ability to grow in salinity and their biochemical traits associated with plant growth promotion.Next, we tested the adhesion on soybean seeds surface and root colonization with the four selectedisolates. Isolate 19 stood out from the rest and was selected for further experiments. This strainshowed positive chemotaxis towards soybean root exudates and a remarkable ability to form biofilmboth in vitro conditions and on soybean roots.Interestingly, this trait was enhancedin high salineconditions, indicating the extremely adapted nature of the bacterium to high salinity. In addition,this strain positively impacted on seed germination, plant growth and general plant health statusalso under saline stress.Conclusions: A bacterium isolate with outstanding ability to promote seed germination and plantgrowth under saline conditions was found.Significance and impact of Study: The experimental approach allowed us to find a suitablebacterial candidate for a biofertilizer intended to alleviate saline stress on crops. This would allowthe use of soil now considered inadequate for agriculture and thus prevent further advancement ofagriculture frontiers into areas of environmental value.