Proteome Analyses Reveal Macrophomina phaseolina's Survival Tools When Challenged by Burkholderia contaminans NZ

A phytopathogenic fungus, Macrophomina phaseolina, which infects a wide range of plants, is an important consideration in agronomy. A jute endophytic bacterium, Burkholderia contaminans NZ, was found to have a promising effect in controlling the fungus in in vitro culture conditions. Using the iTRAQ LC-MS/MS method for quantitative proteomics study, an analysis of the whole proteome of Macrophomina phaseolina with or without B. contaminans NZ challenge identified 2204 different proteins, of which 137 were found to have significant deviation in expression. Kyoto encyclopedia of genes and genomes pathway analysis identified most of the upregulated proteins to be functionally related to energy production (26.11%), as well as defense and stress response (23.45%), while there was significant downregulation in oxidative stress protection pathways (42.61%), growth and cell wall integrity (30.95%), and virulence (23.81%). Findings of this study suggest the development of a battle when the phytopathogen encounters the bacterium. B. contaminans NZ manages to arrest the growth of the fungus and decrease its pathogenicity, but the fungus apparently survives under "hibernating" conditions by upregulating its energy metabolism. This first ever proteomic study of M. phaseolina will go a long way in understanding and developing strategies for its effective control.