A Potential Application of Endophytic Bacteria in Strawberry Production

Endophytic bacteria could be used as a tool to promote plant growth, enhance abiotic stress tolerance, and inhibit plant pathogen growth. More than 100 bacteria, previously tested to have biocontrol activity against fungal pathogens from our lab, were chosen for pathogen inhibition in vitro with antibiosis assays against strawberry specific pathogens. Three potential endophytic bacteria were tested in the greenhouse for disease reduction and growth performance. Finally, field trials were conducted for fruit yield production. Our results showed that three endophytic bacteria significantly inhibited the growth of the strawberry pathogen Colletotrichum gloeosporioides from antibiosis assays and were identified as Bacillus velezensis strains IALR308, IALR585, and IALR619. Inoculation of these bacteria significantly reduced strawberry disease in greenhouse conditions with pathogen infection. Field trials showed that IALR619 has potential to influence marketable fruit yield when strawberry plants were inoculated twice over the growing season. All three bacteria had the ability to produce auxin and to solubilize phosphate. The antibiotics surfactin and iturin were also detected in IALR585 and IALR619. In conclusion, Bacillus velezensis IALR619 has potential inhibition of strawberry pathogen growth in the greenhouse and possible ability to increase marketable fruit yield in the field.