Phenotypes of the ttg1Δ15aa mutant and a TTG1 gene-edited mutant. (a) Trichome formation on leaves of 10-day-old seedlings (up panel), 4-week-old plants (middle panel), and stems of 5-week-old plants (lower panel) of the Col wild type, the ttg1Δ15aa, and the ttg1-c1 mutants. Seeds of the Col wild type, the ttg1Δ15aa, and the ttg1-c1 mutants were germinated and grown in soil pots. Pictures were taken directly or under a Motic K microscope by using an EOS 1100D digital camera at indicated stages. (b) Seed color of the Col wild type, the ttg1Δ15aa and the ttg1-c1 mutants. Pictures were taken under a Motic K microscope by using an EOS 1100D digital camera. (c) Editing status of TTG1 in the ttg1-c1 mutant. The arrow indicates the 440 G deletion in the ttg1-c1 mutant. Underline indicates the PAM site. The mutant was obtained by transforming the Col wild type plants with the pHDE-TTG1 CRISPR/Cas9 construct. Editing status of TTG1 was examined in T1 plants, and Cas9-free homozygous mutant plants were obtained in T2 generation. (d) Root hair formation in the Col wild type, the ttg1Δ15aa, and the ttg1-c1 mutants. Seeds of Col wild type, the ttg1Δ15aa, and the ttg1-c1 mutants were germinated and grown on half MS plates vertically. Pictures were taken from 7-day-old seedlings under a Motic K microscope by using an EOS 1100D digital camera. (e) Mucilage production in the Col wild type, the ttg1Δ15aa, and the ttg1-c1 mutants. Seeds were stained with 0.01% (w/v) Ruthenium red for 2 h, and pictures were taken under a Motic K microscope by using an EOS 1100D digital camera.