Effect of promoter sequence on transient expression of the β-glucuronidase gene in embryogenic calli of Larix × eurolepis and Picea mariana following microprojection

Abstract

The transient expression of the β-glucuronidase reporter gene was compared in embryogenic cell lines of Larix × eurolepis (L. decidua × L. leptolepis) and Picea mariana after introduction of eight vectors containing different promoter sequences using the Dupont Biolistic™ particle delivery system. Transient β-glucuronidase gene expression was highest in cells of both species after bombardment using the wheat abscisic acid inducible Em gene promoter. Transient β-glucuronidase gene expression was comparable in P. mariana and L. × eurolepis for all vectors, with the exception of the rice actin promoter that yielded higher activity in P. mariana than in L. × eurolepis. The Em gene promoter proved inducible by abscisic acid; upon the addition of abscisic acid to the culture medium, β-glucuronidase gene expression was increased 2.3- and 4.4-fold for L. × eurolepis and P. mariana, respectively. Investigation of β-glucuronidase gene expression over time showed that all transient activity disappeared 16 days after microprojection. Key words: Larix, Picea, transformation, β-glucuronidase, tissue cultures.