Consortium of Plant Growth – Promoting Rhizobacteria Enhances Oilseed Rape (Brassica Napus L.) Growth Under Normal And Saline Conditions

Abstract Development of a preparation, which stimulates plant growth under normal and saline conditions, and protects against fungal infections, would increase crop yields and reduce damage in agriculture. This study was conducted using bacterial isolates from rape rhizosphere as a plant growth promoter and an alternative to chemical fertilizers. Three from fifty bacterial isolates: B14 (Pseudomonas grimontii), B16 (Sphingobacterium kitahiroshimense), and B19 (Microbacterium oxydans) showed the best in vitro plant growth – promoting (PGP) characteristics. B14 strain inhibited the growth of B. cinerea, C. acutatum, and P. lingam and B14 - inoculated plants had the best ability to grow in salt concentrations of 100 mM NaCl. Moreover, B14, B16 and B19 isolates coded for several genes involved in PGP activities, aimed at improving nutrient availability, resistance to abiotic stress, and fungal pathogen suppression. Microbial consortium (B14, B16, and B19) had the best effect on rape growth, significantly increasing chlorophyll content index, shoot length and number of live leaves, compared to the untreated control and single inoculant treatments. Consortium also induced the plants tolerance to salt stress. The genomic information as well as the observed traits, and beneficial attributes towards rape, make the rhizobacterial consortium an ideal candidate for further development as biofertilizers.