Characterization of Jumonji-domain containing proteins in Arabidopsis thaliana
Jumonji-C (JmjC) domain containing proteins have been shown to play a critical role in regulating gene expression by regulating chromatin remodeling in a variety of organisms. In Arabidopsis, JmjC protein family consists of 21 members, some of which have been shown to be involved in regulating histone demethylation. Most of these proteins have been characterized for their role in regulating plant development, especially for their role in regulating flowering time. Here we report characterization of three JmjC domain containing proteins - JUMONJI1, JUMONJI2, and JUMONJI27 and show that they play a critical role in regulating both pathogen defense and flowering time. In addition, double (jmj2 jmj1, jmj27 jmj1, jmj27 jmj2) and triple mutants (jmj27 jmj2 jmj1) were generated to determine their epistatic relationship. Flowering time and the response of the double and triple mutants to pathogen infection was compared to single mutants and wild type plants. Results of these analyses were used to determine epistatic relationship among these genes. Our analysis revealed that JMJ1 is upstream of JMJ27, and JMJ2 is downstream of JMJ27. These results were confirmed by expression analysis of JMJ1, JMJ2, and JMJ27 in single, double and triple mutants. Our results suggest that JMJ1, JMJ2, and JMJ27 regulate each other to fine tune bacterial defense responses and flowering time in Arabidopsis.