Role of Histone Demethylases in Pathogen Defense

Donal Erickson

Abstract

Understanding the roles of plant defense genes is important because crop destruction as a result of plant pathogens is a major problem to farmers. With a growing global population and an increasing portion of crops being used in renewable fuels, understanding plants' defense mechanisms is becoming more important. Increasing our understanding of plant defense will open the doors to transgenic plants that are resistant to pathogens through natural methods, as opposed to the use of pesticides. Histone modification has been previously shown to be involved in many biological processes and recent research has shown that there is a link between chromatin remodeling and plant defense. The Arabidopsis gene JMJ17/27, an H3K9me1/2/3 demethylase, was recently found to be critical for defense against virulent and avirulent strains of Pseudomonas syringae.

With the knowledge that JMJ1, 2, 4, and 18, histone demethylases in the same gene family as JMJ17/27, are strongly induced in Arabidopsis when exposed to virulent pathogen, we set out to determine if these 4 genes have a similar function to JMJ17/27. Knockout mutants were used in this study to give an understanding of what role these genes play in plant defense. We tested the susceptibility of JMJ1, 2, 4, and 18 knockout mutants to a virulent strain of P. syringae and the fungal pathogen Botrytis cinerea when compared to CS60000 wild-type plants. Our studies showed that jmj2 mutants were more susceptible to virulent P. syringae and jmj1, 4, and 18 mutants were more susceptible to B. cinerea. These results indicate that jmj1, 2, 4, and 18 are involved in the regulation of plant defense. These results will aid us in understanding the role of JMJ genes in regulating defense against pathogens in A. thaliana and will allow future research of these genes to continue.