EM GENE-EXPRESSION DURING SOMATIC EMBRYOGENESIS IN THE MONOCOT TRITICUM-AESTIVUM L

We have used in vitro cultures initiated from immature zygotic embryos of the monocot Triticum aestivum, variety Chinese Spring, to investig ate some features of the transcriptional regulation of the Em gene. A 210-bp cDNA fragment internal to the coding region of the Em gene was amplified by PCR, cloned and used as a probe in northern analyses. Em gene expression was found to be associated with cultures displaying an embryogenic potential and, more precisely, with the presence of somat ic embryos. The time-course of Em gene expression was thereafter monit ored, by PCR and northern analysis, from the initiation of cultures un til the appearance of embryogenic structures and was shown to be tempo rally regulated during the somatic embryogenesis process. Finally, the Fm protein was observed in both somatic embryos and embryogenic cultu res whereas it was not detected in non-embryogenic cultures. Our resul ts, obtained from a monocot, ask the question of whether Em gene expre ssion could be used as a universal late marker of somatic embryogenesi s.