(79a) Development of Plant PGIP as Novel Pest Control Method

There is an urgent need for the development of novel antibacterial agent, especially towards the more-difficult-to-kill gram-negative bacteria, and bacteria of antibiotic resistance. Plant natural products, including small molecules and macromolecules, are important sources for novel antibiotics. Phospholipids are the major component of biological membranes including cell membranes, and phospholipase hydrolyzes phospholipids. Previous extensive studies on phospholipase A2s implies the important role during inflammation, and the group IIA secreted PLA2 has been reported to be bactericidal against gram-positive bacteria through membrane hydrolysis, but not as efficient towards gram-negative bacteria. Plastid Lipase 1 (PLIP1) from Arabidopsis thalian shows promise. Plant phospholipases that can efficiently hydrolyze the major lipids of bacteria cell membrane is a promising alternative antibacterial agent, through a distinct bactericidal mechanism from conventional antibiotics. To test the antibacterial activities, a plant phospholipase was selected and reconstituted in Saccharomyces cerevisiae and showed clear inhibition to E.coli growth. Continuous evolution was conducted to evolve phospholipase with enhanced potency towards E. coli. The phospholipase of enhanced activity can be developed as an efficient antimicrobial agent towards gram-negative bacteria.