Fishing for Genes Involved in Nonhost Disease Resistance Lead to the Identification of a Gene Involved in Ribosome Processing

Nonhost resistance is the resistance exhibited by all the cultivars of a plant species against all races of a particular pathogen. To identify genes involved in nonhost disease resistance, we used a virus-induced gene silencing based fast forward genetics screen of a Nicotiana benthamiana cDNA library obtained from mixed elicitors treated leaves. In the present study, a cDNA clone named 19A10 was identified as one of the candidate genes involved in nonhost resistance. 19A10 silenced N. benthamiana plants compromised nonhost resistance against several bacterial pathogens. Sequence analysis of 19A10 showed the presence of BRIX domain.  BRIX domain containing proteins are shown to be involved in the maturation of 60s ribosomal subunit. In order to determine the function of 19A10 in plant defense, we performed a yeast-two hybrid screen to identify plant proteins that interact with 19A10. We have now identified at least 12 proteins that interact with 19A10.  Further characterization of these proteins will be presented.