Abstract
Little is known about the physiological responses of higher plant cells during the early stages of embryogenesis and the genes that are involved in these responses. Carrot is an appropriate plant for the study of somatic embryogenesis as a model of zygotic embryogenesis. The system of stress induction of carrot somatic embryogenesis is useful for isolating genes expressed during embryogenesis, as embryogenic competence and the expression of certain embryo-specific genes increases with increased stress. Fluorescent differential display (FDD) was performed to isolate stress-induced genes in carrot somatic embryos, and five genes were isolated as embryonic tissue-specific genes. One of these genes was expressed until the early torpedo-shaped stage of zygotic embryogenesis. This result suggested that in the stress-induction system of carrot somatic embryos, embryo-specific genes expressed in the early stages of embryogenesis were induced during somatic embryo induction by stress treatment, concomitant with acquisition of embryonic competence. Unique genes expressed during early embryogenesis can be isolated from carrot by combining the appropriate experimental system and FDD. This strategy could be applied to many plant species for which genome information is not yet available.
