Systemic Response Stimulated By Bacillus Spp. Can Manage Meloidogyne Incognita Population Density in Gossypium hirsutum

Meloidogyne incognita is a plant parasitic nematode that causes economic losses in upland cotton. Management of the nematode includes nematicides, cultural control and biological control. Due to the inexpensive cost and low environmental impact, biological control agents are becoming more popular as a control method for M. incognita. Biological control agents can work by direct or indirect antagonism of their target pathogen. Indirect antagonism includes the upregulation of plant defense pathways. This includes the induced systemic resistance pathway, which utilizes jasmonic acid and is stimulated by plant-growth promoting rhizobacteria, and the systemic acquired resistance pathway, which utilizes salicylic acid. Determining which pathway a biological control agent, with an indirect method of antagonism, stimulates is essential to the integration of the biological control agent into a successful pest management program. This research will examine five Bacillus species and their ability to stimulate a systemic response to M. incognita within cotton. Experiments will include a greenhouse test, an in vitro assay, a split root assay and a RT-qPCR assay. Results of the greenhouse test will determine the efficacy of the Bacillus sp., while results of the in vitro assay and split root assay will determine whether the mechanism of action is direct or indirect for each species. The RT-qPCR assay will further elucidate whether systemic resistance is occurring within the cotton plant. The findings of this research will help implement these biological control agents in an integrated pest management program for nematodes, specifically M. incognita.