COL13 regulates hypocotyl elongation under red-light conditions
To characterize the role of COL13 in plants, we obtained the
corresponding Arabidopsis T-DNA insertion mutant
(GK-657F04-023194, termed col13 in the following; Fig.S1a) from
GABI-Kat, Max Planck Institute for Plant Breeding Research
(Rosso et al., 2003); the mutation was
verified by PCR (Fig.S1b), which amplify the sul gene by using
the primers listed in Supplementary Table 1. To confirm that the
phenotype of the col13 mutant was indeed caused by disruption of
the COL13 gene, we generated COL13 overexpression (OX)
(Fig.2a) and COL13 RNAi transgenic lines (Fig.2b) for comparison.
To examine whether COL13 is involved in light responses,
wild type (WT), COL13 RNAi
and col13 seedlings were germinated and grown in different light
(White, red, blue), as well as dark condition. As shown in Fig.S1c,
under white or red light, the COL13 RNAi and col13seedlings had longer hypocotyls than WT, while in blue light or dark
condition, the hypocotyl length of all seedlings were no significant
difference. Therefore, our research focus on red light. For further
study, COL13 OX, COL13 RNAi, col13 and WT seedlings
were germinated and grown in red light. We found that the COL13OX seedlings had shorter hypocotyls than WT in red light (Fig. 2c,d), in
contrast, the COL13 RNAi and col13 seedlings had longer
hypocotyls than WT under the same conditions (Fig. 2c, e). These findings
suggest that COL13 acts as a positive regulator of red light-mediated
inhibition of hypocotyl elongation.