Dear Editor,RNA-directed DNA methylation (RdDM) is a mechanism for achieving sequence-specific de novo DNA methylation.ROS1 encodes a DNA glycosylase/lyase,which demethylates DNA (Gong et al.,2002).ros1 causes the transcriptional gene silencing (TGS) of the LUCtransgene driven by the stress-responsive RD29A promoter and endogenous RD29A (Gong et al.,2002).From our previous screening for second-site suppressors of ros1,NRPD4 and RDM4,first as RdDM components,were identified (He et al.,2009a,2009b).To discover new regulators of the RdDM pathway,we conducted an efficient genetic screen in this study and found a novel RdDM component:AtRRP6L1.