Improved Viability of Spray-Dried <i>Pantoea agglomerans</i> for Phage-Carrier Mediated Control of Fire Blight

oleh: Nassereldin Ibrahim, Darlene Nesbitt, Qian (Tracy) Guo, Janet Lin, Antonet Svircev, Qi Wang, Joel T. Weadge, Hany Anany

Format: Article
Diterbitkan: MDPI AG 2024-02-01

Deskripsi

Fire blight, caused by <i>Erwinia amylovora</i>, is a devastating bacterial disease that threatens apple and pear production. It is mainly controlled by using antibiotics, such as streptomycin. Due to development of <i>E. amylovora</i> resistant strains and the excessive agricultural use of antibiotics, there is an increased awareness of the possibility of antibiotic resistance gene transfer to other microbes. Urgent development of biocontrol agents (BCAs) is needed that can be incorporated into integrated pest management programs as antibiotic alternatives. A novel phage-carrier system (PCS) that combines an antagonistic bacterium, <i>Pantoea agglomerans</i>, with its ability to act as a phage-carrier bacterium for <i>Erwinia</i> phages has been developed. The low viability of <i>P. agglomerans</i> cells following spray-drying (SD) has been a challenge for the industrial-scale production of this PCS. Here, an SD protocol was developed for <i>P. agglomerans</i> by modifying the growth medium and bacterial cell formulation using D(+)-trehalose and maltodextrin. The developed protocol is amenable to the industrial-scale production of the BCA/PCS. The <i>P. agglomerans</i> viability was greater than 90% after SD and had a shelf life at 4 °C of 4 months, and reconstituted cells showed a 3 log reduction in <i>E. amylovora</i> counts with a pear disc assay.