Table 1.

Arabidopsis mutants used in this study

Gene name	AGI code	Protein function	Mutant allele	Reference
AGO1	At1g48410	slicer in RISC	ago1-25	Morel et al., 2002
			ago1-27	Morel et al., 2002
AGO7	At1g69440	slicer in RISC	ago7-2	SALK_095997a
DCL2	At3g03300	dicer	dcl2-1	Xie et al., 2004
DCL4	At5g20320	dicer	dcl4-2	Yoshikawa et al., 2005
HEN1	At4g20910	methyltransferase	hen1-6	Li et al., 2005
HST	At3g05040	transporter	hst-1	Telfer and Poethig, 1998
NRPD1a/SDE4	At1g63020	polymerase	nrpd1a-3	Herr et al., 2005
RDR2	At4g11130	RDR	rdr2-4	Smith et al., 2007
RDR6/SDE1/SGS2	At3g49500	RDR	sgs2-1	Elmayan et al., 1998
			rdr6-11	Peragine et al., 2004
			rdr6-15	Allen et al., 2004
SDE3	At1g05460	RNA helicase	sde3-4	Vazquez et al., 2004b
			sde3-5	SALK_003347a
SGS1	Unknown	Unknown	sgs1-1	Elmayan et al., 1998
SGS3/SDE2	At5g23570	CC-domain	sgs3-1	Mourrain et al., 2000
		protein	sgs3-11	Peragine et al., 2004

^aSALK T-DNA insertion mutant (Alonso et al., 2003).