Isolation of rhizobacteria associated with tomato (Solanum lycopersicum L.) and its potential to promote plant growth

Abstract

An alternative to reduce the high doses of inorganic fertilizers in crops such as tomatoes is the use of plant growth promoting rhizobacteria (PGPR). The objective of this research was to isolate and characterize strains of rhizobacteria as well as to evaluate their potential to promote plant growth in tomato seedlings. Soil samples were collected from the tomato rhizosphere in La Bajada community, Municipality of Coyuca de Catalán, in the State of Guerrero. A total of 70 strains of rhizobacteria were isolated, of which 12 were selected based on their ability to produce indoles, solubilize phosphates, and produce siderophores. The strains were identified at the molecular level and it was found that they belong to seven species: Arth-robacter pokkalii, Pseudomonas aeruginosa, A. enclensis, Bacillus licheniformis, B. drentensis, Staphylo-coccus equorum, and Pseudarthrobacter spp. The results obtained in the seedbed experiment showed that the JLB4 strain was the best since it significantly increased (P ≤ 0.05) the variables height, root volume, fresh weight of part area, fresh weight of stem and total dry weight, as well as content of N, P and K, with respect to the control and the reference strain P61. The JN24 strain showed greater diameter and height of the seedlings and JLB2 was the best in the foliar area and the JP4 strain in the specific foliar area. The A. pokkalii JLB4 strain, which had the greatest effects on seedlings with a 78 % increase in biomass, has great potential and could be used in tomato production under greenhouse conditions.