ENZYME-TARGETED ANTIMICROBIALS FOR PLANT DISEASE CONTROL

NO MICROBIOCIDE IS AVAILABLE THT IS EFFECTIVE AGAINST SUCH MAJOR PHYTOPATHOGENS AS SPECIES OF XANTHOMONAS, ERWINIA AND PSEUDOMONAS SYRINGAE. THESE PROKARYOTE PATHOGENS POSSESS A BIOCHEMICA PATHWAY FOR BIOSYNTHESIS OF AMINO ACIDS THAT CON-TAINS ENZYMES WHICH HAVE IDEAL POTENTIAL AS TARGETS FOR ANTIMICROBIAL ATTACK. PROSPECTS FOR SELECTIVE ACTION AGAINST THE BACTERIAL PATHOGEN AND NOT THE PLANT HOST ARE EXCELLENT BECAUSE PLANTS UTILIZE A DIFFERENT BIOCHEMICAL PATHWAY FOR AROMATIC AMINO ACID BIOSYSNTHESIS. TOXICITY PROBLEMS FOR' MAN AND ANIMALS ARE NOT ANTICIPATED BECAUSE THE PATHWAY OF AROMATIC AMINO ACID BIOSYNTHESIS IS TOTALLY ABSENT IN MAM- MALS. DERIVATIVES OF PATHWAY INTERMEDIATES THAT ARE UNIQUE TO PHYTOPATHOGENS WILL BE PREPARED THAT MIMIC THE NATURAL COMPOUNDS IN THEIR METABOLIC ROLES AS SUBSTRATE AND/OR ALLO-STERIC AGENT. CHEMICAL MODIFICATIONS WILL BE ORIENTED TO OBJECTIVES OF PHYTOXICITY. ANTIMICROBIAL CHEMICALS THAT ACTAS IRREVERSIBLE INHIBITORS WILL BE SOUGHT. NEW DERIVATIVES DESIGNED AS ENZYME INHIBITORS WILL BE TESTED FOR ABILITY TO INHIBIT GROWTH OF PHYTOPATHOGENIC SPECIES BY USE OF AGAR DIFFUSION METHODOLOGY. RAPIDLY GROWING SUSPENSION CELL CUL-TURES OF NICOTIANA SILVESTIS (WHICH REQUIRE AROMATIC AMINO ACIDS FOR THE PRIMARY GROWTH PROCESS) WILL BE USED AS A SEN-SITIVE TEST SYSTEM TO MONITOR LACK OF PHYTOTOXICITY.