Inoculation of Pseudomonas mutant strains can improve growth of soybean and corn plants in soils under salt stress

COSTA GUTIERREZ SB; RAIMONDO EE; LAMI, MJ; VINCENT PA; ESPINOSA URGEL M; RICARDO E DE CRISTOBAL

Rhizosphere

Elsevier BV

Lugar: Netherlands; Año: 2020

2452-2198

In the last decades, the applications of Plant Growth Promoting Rhizobacteria (PGPR) as inoculants forenhancing crops yield under different stress conditions have reached enormous interest. Pseudomonas putidaKT2440 is a well-known rhizobacteria capable of colonizing roots of agronomically important crops. This workaims to evaluate three P. putida KT2440 mutants (mus-20, mus-42, and EU206), which have non-biofilm producingand exopolysaccharide overproducing phenotypes, for their potential as PGPR on soybean and corn plantsunder saline stress. Experimental studies showed that KT2440 and its mutants were effective in three main PGPRproperties: solubilization of phosphates and synthesis of indolic compounds and siderophores. Notably, indoliccompounds synthesis increased in mus-20 and EU206 strains. Furthermore, all evaluated strains were tolerant tosaline stress. Bacterial inoculation of soybean and corn seeds was effective both in vitro and in vivo tests, even athigh salt concentrations (80 and 120 mM NaCl). Among mutant bacteria, EU206 strain seems to be the mostefficient PGPR by significantly increasing seed germination, shoot and root lengths, and fresh and dry weights ofplants compared to non-inoculated controls, in in vivo tests under saline condition, mainly in both corn plants.These results suggest that inoculation with the P. putida KT2440 mutant strains is an appropriate strategy toenhance the growth of soybean and corn plants, so they might be employed for promoting regional crops growthat field scale using natural saline soils.