(a) GFP sensor including 3′UTR with a miR845b target site
and driven by the UBIQUITIN10 (UBQ10) promoter
in wild type and dcl1-5/+ heterozygous background. GFP
expression was restored in dcl1 pollen, allowing
FACS-purification of wild type, dcl1, dcl2/4 and
dcl1/2/4 pollen grains. Scale bars represent 30 μm.
(b) Loss of GFP siRNA was detected in dcl1,
dcl2/4 and dcl1/2/4 pollen grains,
indicating that miR845b triggers DCL2/4-dependent secondary siRNA from the GFP
transgene. (c) Small RNA sequencing from wild type and mutant
FACS-sorted pollen revealed that 21- and 22-nt TE siRNA were lost in the
dcl2/4 mutants, while miRNAs were depleted in
dcl1. (d) miR845a and miR845b were depleted in
dcl1 mutant and Ler-0 pollen, but miR845b was restored in
transgenic Ler-0 plants expressing Col-MIR845b (Ler:MIR845b). (e)
21- and 22-nt TE-derived siRNA levels were also depleted in wild-type Ler-0
pollen, but restored in transgenic Ler:MIR845b. RPM, reads per million.