Agrobacterium-mediated transient expression may be regarded as a promising method for inexpensive large-scale production of recombinant proteins. We optimized the protocol of transient expression in Nicotiana benthamiana and compared six Australian species of Nicotiana as hosts for transient expression. The transient expression of GFP under 35S CaMV promoter was observed in all species tested, although the GFP content in leaves of N. benthamiana, N. exigua, and N. excelsior was significantly higher (3.8, 3.7, and 2.0% TSP, respectively). Usage of viral-based expression system resulted in considerable increase of GFP accumulation in N. excelsior and N. benthamiana (63.5 and 16.2% TSP, respectively). We displayed that N. excelsior has the best characteristics in regard to biomass yield as well as GFP accumulation level for both types of the expression cassettes tested.

Twenty-nine cybrids possessing an Atropa belladonna nuclear genome and a Nicotiana tabacum plastome were selected from two independent protoplast fusion experiments. In contrast to the previously described reciprocal, green and fertile cybrids with a Nicotiana nuclear genome and an Atropa plastome (Kushnir et al. 1987), the plants obtained were totally chlorophyll-deficient. An Atropa nuclear genome and a Nicotiana plastome from these chlorophyll-deficient cybrids were combined with an Atropa or a Scopolia plastome and a Nicotiana nuclear genome, respectively, in control fusion experiments. All of these nuclear genome/plastome combinations gave rise to normal, green plants. Therefore, we conclude that an N. tabacum plastome is incompatible with an A. belladonna nuclear genome.

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Aim. To study the influence of antibiotics Ceftriaxone and Timentin on the morphogenic calli and roots formation, shoots regeneration in two bread wheat cultivars Triticum aestivum L., to study effect of Ceftriaxone on the growth dynamics of plants. Methods. In vitro plant tissue culture, analysis of Variance, correlation and regression analysis. Results. The influence of β-lactam antibiotics Ceftriaxone and Timentin on morphogenetic processes (morphogenic calli formation, shoots regeneration and rhizogenesis), was studied in apical 18-day-old wheat calli. Two wheat genotypes of different growth habits, winter and winter-spring, were used. Conclusions. Timentin and Ceftriaxone stimulate morphogenic calli formation in bread wheat apical calli. As compared to Timentin, Ceftriaxone has strong concentration-dependent and genotype-dependent influence on shoots regeneration. The roots formation depended primarily on the wheat genotype, independently from an antibiotic applied. The presence of Ceftriaxone in culture medium stimulates rooting and growth of regenerating plants as well as their biomass increment.