Multi-Trait Wheat Rhizobacteria from Calcareous Soil with Biocontrol Activity Promote Plant Growth and Mitigate Salinity Stress

Anastasia Venieraki; Styliani N Chorianopoulou; Panagiotis Katinakis; Dimitris L Bouranis

doi:10.3390/microorganisms9081588

Multi-Trait Wheat Rhizobacteria from Calcareous Soil with Biocontrol Activity Promote Plant Growth and Mitigate Salinity Stress

Microorganisms. 2021 Jul 26;9(8):1588. doi: 10.3390/microorganisms9081588.

Authors

Anastasia Venieraki¹, Styliani N Chorianopoulou², Panagiotis Katinakis³, Dimitris L Bouranis²

Affiliations

¹ Laboratory of Plant Pathology, Crop Science Department, Agricultural University of Athens, Iera Odos 75, 118 55 Athens, Greece.
² Laboratory of Plant Physiology and Morphology, Crop Science Department, Agricultural University of Athens, Iera Odos 75, 118 55 Athens, Greece.
³ Laboratory of General and Agricultural Microbiology, Crop Science Department, Agricultural University of Athens, Iera Odos 75, 118 55 Athens, Greece.

Abstract

Plant growth promoting rhizobacteria (PGPR) can be functional microbial fertilizers and/or biological control agents, contributing to an eco-spirit and safe solution for chemical replacement. Therefore, we have isolated rhizospheric arylsulfatase (ARS)-producing bacteria, belonging to Pseudomonas and Bacillus genus, from durum wheat crop grown on calcareous soil. These isolates harbouring plant growth promoting (PGP) traits were further evaluated in vitro for additional PGP traits, including indole compounds production and biocontrol activity against phytopathogens, limiting the group of multi-trait strains to eight. The selected bacterial strains were further evaluated for PGP attributes associated with biofilm formation, compatibility, salt tolerance ability and effect on plant growth. In vitro studies demonstrated that the multi-trait isolates, Bacillus (1.SG.7, 5.SG.3) and Pseudomonas (2.SG.20, 2.C.19) strains, enhanced the lateral roots abundance and shoots biomass, mitigated salinity stress, suggesting the utility of beneficial ARS-producing bacteria as potential microbial fertilizers. Furthermore, in vitro studies demonstrated that compatible combinations of multi-trait isolates, Bacillus sp. 1.SG.7 in a mixture coupled with 5.SG.3, and 2.C.19 with 5.SG.3 belonging to Bacillus and Pseudomonas, respectively, may enhance plant growth as compared to single inoculants.

Keywords: arylsulfatase (ARS)-producing bacteria; bacterial strain compatibility; biofertilizers; plant growth promoting rhizobacteria (PGPR); plant growth promoting traits; salinity tolerance.