In vitro PGPR properties and osmotic tolerance of different Azospirillum native strains and their effects on growth of maize under drought stress

Abstract

Osmotic variations in the soil can affect bacterial growth diminishing the number of inoculated bacteria. In a scenario of water deficit having tolerant bacteria would be beneficial to achieve a better response of the plant to stress. Thus, selection of more resistant bacteria could be useful to design new inoculants to be used in arid zones. In this sense, a group of Azospirillum isolates deposited in INTA collection was characterized in order to select strains tolerant to osmotic stress. The results obtained demonstrated that Az19 strain has similar in vitro PGPR characteristics to Az39, the most used strain in Argentina for inoculants industries, with the advantage of a better tolerance to osmotic and salt stress. Inoculation of maize plants with this strain resulted in a better response against water deficit compared to Az39 strain, encouraging us to further study the behavior of this strain in greenhouse and field trials in view of developing new inoculants suitable for areas with water deficit.

Inoculation With Growth-Promoting Bacteria Associated With the Reduction of Phosphate Fertilization in Sugarcane

“…According to some authors, the inoculation with Bacillus sp. (Vardharajula et al, 2011) or A. brasilense (García et al, 2017) improved proline content in plants and make them more resistant to drought stress. The Arabidopsis plants when inoculated with A. brasilense resulted in the production of high level of abscisic acid.…”

Promising bacterial genera for agricultural practices: An insight on plant growth-promoting properties and microbial safety aspects

“…were conducted on wheat (Bashan et al, 1990;Noreen and Noreen, 2014), rice (García de Salamone et al, 2012) and soybean (Bashan et al, 1990). More recently, the interest in Azospirillum strains has increased due to positive results for plant growth enhancing in soils under osmotic stress (Fasciglione et al, 2015;García et al, 2017;Gonzalez et al, 2015).…”

Ancient wheat varieties have a higher ability to interact with plant growth‐promoting rhizobacteria

“…Modern breeding is typically carried out under optimal agronomic conditions, which is likely to limit the potential added value resulting from beneficial plant‐microbe interactions (Sasaki et al, ; Schmidt, Bowles, & Gaudin, ; Weese, Heath, Dentinger, & Lau, ). In the case of soil bacteria, this involves plant growth‐promoting rhizobacteria (PGPR), which may stimulate root growth, improve nutrient uptake (Kumar, Maurya, & Raghuwanshi, ; Majeed, Kaleem Abbasi, Hameed, Imran, & Rahim, ), alleviate plant stress (Barnawal et al, ; Furlan et al, ; García et al, ; Pande, Ns, & Bodhankar, ), or protect the plants from pathogens (Díaz Herrera, Grossi, Zawoznik, & Groppa, ; Keshavarz‐Tohid et al, ). These effects rely on various modes of action, such as increasing nutrient availability, modulating plant hormonal balance (Cassán, Vanderleyden, & Spaepen, ; Saleem, Arshad, Hussain, & Bhatti, ), and/or producing bioactive metabolites (Couillerot et al, ; Vacheron et al, ).…”