aStrict TATA box sequence detected on both ends of BD PRO.
bStrict TATA box sequence detected on either end of BD PRO.
RD PRO: Randomly obtained promoter regions extending 1000 bp upstream of the start ATG codon of each random gene from the genome of each species. Lengths of the RD PROs corresponded to the mean lengths of the BD PROs of each species. Mean promoter lengths: maize: 440 bp; sorghum: 440 bp; rice: 540 bp; soybean: 570 bp; Arabidopsis: 460 bp.