Transcript analysis in A. thaliana knockout mutants. (A) Leaf material was harvested from wild type or homozygous atwrky36 knockout mutant plants and the Sucrose Prep was used for RT-PCR analysis with gene specific primers. The T-DNA is located in the first intron of AtWRKY36 and was occasionally transcribed and spliced out since a cDNA product corresponding to a segment of mature RNA is detected in the knockout mutant. The second column is digitally enhanced to highlight the cDNA product detected in the knockout line. (B) Leaf material from wild-type and a homozygous atwrky70 mutant were sampled using the 'Touch-and-Go' method (see text for details). The T-DNA insertion in the gene prevented PCR amplification of both DNA and cDNA products (larger than 4 kb).