Evaluation of the Growth-Promoting Potential of Endophytic Bacteria Recovered from Healthy Tomato Plants

The study examined the plant growth-promoting potential of 38 endophytic bacterial isolates recovered from healthy tomato plants. Eight isolates were selected as the most efficient in improving the plant height by 30.5-35.9%, the aerial part fresh weight by 47.4 -56.9%, the maximum root length by 17.3- 28.3%, and the root fresh weight by 44.7- 58.8% compared to control. They were morphologically and biochemically characterized and identified using 16S rDNA sequencing genes as Stenotrophomonas maltophilia CT12, S. maltophilia CT13, S. maltophilia CT16, Pseudomonas geniculata CT19, B. amyloliquefaciens CT32, B. subtilis subsp. inaquosorum CT43, B. licheniformis SV4, and B. subtilis SV5. All isolates were shown able to produce indole-3-acetic acid and displayed pectinolytic activity. Phosphate solubilization ability was recorded in S. maltophilia CT13, S. maltophilia CT16, B. subtilis subsp. inaqosorum CT43 and B. licheniformis SV4. This study demonstrates that healthy tomato plants may be naturally colonized by beneficial endophytic bacteria with growth-promoting potential useful for the improvement of tomato growth.