Characterization of a temperature-sensitive carrot cell mutant impaired in somatic embryogenesis

Among the various carrot cell mutants, temperature-sensitive for embryogenesis, line ts59, blocked at the globular stage, was characterized. A biological characterization indicates that the function missing or altered in ts59 is necessary two times during development: the first, 5 days after the onset of embryogenesis and the second, at the transition between heart- and torpedo-shaped embryos. Fusion experiments of protoplasts of ts59 with a wild-type line, inactivated with iodoacetate, indicate dominance of the ts59 mutation. A biochemical analysis was carried out of various embryonic markers of ts59 and compared with wild-type. A remarkable alteration was found in the pattern of heat-shock proteins whose expression was shown to vary during development. © 1988.