Abstract
Because of overexpression of CDG1 gene which encodes a receptor-like protein kinase belonging to the RLCKVII subfamily, cdg1-D shows pleiotropic phenotype including dwarfism, exaggerated leaf epinasty, and twisted or spiral growth in hypocotyl, inflorescence stem, and petiole. Hypocotyl of cdg1-D is significantly longer than those of wild type under white-light condition, showing abnormal growth regulation by light. When treated with high concentrations of brassinolide, light-grown wild-type seedlings showed long hypocotyl and strong leaf epinasty as observed in cdg1-D seedlings. We screened for suppressors of cdg1-D, and isolated two independent intragenic suppressors which restored all the phenotype of cdg1-D. However, the homozygous suppressor mutants showed normal morphology and responded to brassinolide in a similar manner to wild type. These suggest that CDG1 gene possibly interferes with synthesis or signal transduction of brassinosteroid when overexpressed, but is not an essential factor for them in wild type.
