Characterization of the Extracellular Protease of Pseudomonas fluorescens A506
Presented by Meadow Anderson
Mentor: Joyce Loper
USDA

Pseudomonas fluorescens A506 is a bacterium used for the biological
control of fire blight, a disease affecting pear and apple trees. The
extracellular protease that it produces is implicated in the breakdown of
a peptide antibiotic produced by another biological control bacterium,
Pantoea agglomerans 252, preventing otherwise complementary bacteria from
being used together to enhance disease control. Preliminary studies with
a mutant of A506 deficient in extracellular protease indicate that without
this protease, antibioisis is not compromised. The extracellular protease
is being isolated and characterized to allow more direct examination of
its interaction with the peptide antibiotic of 252. Characterization will
include: size determination, pH and temperature stability, ion
requirements, and specificity.