Bacillus as a Bio-control Against Phytophthora

In these times of agriculture there are many problems and one is a plant pathogen called Phytophthora.   Phytophthora causes devastating disease problems on many different crops by attacking the roots and water carrying vessels of infected plants.  One particular strain of Phytophthora, P. capsici, is one of the most important pathogens of chile peppers.  Several species of Bacillus, a gram positive bacteria, have been shown to be antagonists of plant pathogens, and have potential to be used as biocontrol agents to reduce or prevent disease.  The use of Bacillus and other biocontrol agents is becoming popular as a natural alternative to chemical based control of plant pathogens.  Bacillus naturally defends its surroundings from other bacteria and fungi by producing antibiotics.   Our goal is to use Bacillus as a natural Bio-control against Phytophthora.  The first step in this project was to isolate Bacillus strains from soil by using selective media and heat treatment of soil to kill off other microbes prior to isolation.  Isolated Bacillus strains were identified by DNA fingerprinting and then tested for the ability to suppress Phytophthora in both culture based plate inhibition assays and plant protection assays.  Over the course of this project we screened 69 Bacillus isolates, identified 12 that appeared to inhibit growth of Phytophthora in culture and 4 that may reduce Phytophthora symptoms chile plants.  The use of Bacillus as a natural pesticide against Phytophthora is showing promise as a natural disease control method in chile production.

Research supported by Grant R25 GM048998-13.