Immunomodulation of ABA function affects early events in somatic embryo development

Immunomodulation of abscisic acid (ABA) function during somatic embryogenes is of Nicotiana plumbaginifolia has been used to demonstrate for the first time the effect of this phytohormone on early embryonic events. A homozygou s rransgenic line constitutively expressing an anti-abscisic acid (ABA) sin gle chain fragment variable antibody in the endoplasmic reticulum was estab lished. Development of somatic embryos from the transgenic line and the wil d type was compared. The AEA biosynthesis mutants aba1 and aba2 and wild ty pe cultures treated with the ABA biosynthesis inhibitor fluridone were also used for the comparative investigations. The development of embryonic stru ctures was disturbed in the early stages of all cultures in which ABA funct ion was blocked or which were ABA-deficient. After ABA complementation of t he in vitro cell cultures normal somatic embryo development was restored.