Genome flux in tomato auto- and auxo-trophic cell clones cultured in different auxin/cytokinin equilibria. I. DNA multiplicity and methylation levels

Abstract

An analysis of the effect of changing physiological conditions on genetic stability, in terms of epigenetic changes, such as DNA, methylation patterns, and multiplicity of repetitive DNA, was carried out on tomato cell clones grown on media supplemented with different auxin/cytokinin ratios. The effect of endogenous variation in phytohormone equilibria was also indirectly analysed through a comparison of auxotrophic or habituated (autotrophic) cell clones and the differentiated leaf tissue. The data obtained showed significant variation in methylation and multiplicity levels both between clones and between treatments, clearly suggesting a contemporary influence of exogenous hormonal treatments and of the initial/endogenous physiological state of the treated tissue on both phenomena studied.

Characterisation of 3′ transgene insertion site and derived mRNAs in MON810 YieldGard® maize

“…Seeds were sown on a soil-vermiculite mixture and grown in a greenhouse at 24 ± 1°C T, under long day light conditions for 2 weeks after germination. DNA was extracted from frozen leaves of each germinated plant as described in Bogani et al (1995).…”

Selection for virus resistance in tomato exposed to tissue culture procedures

“…Similar procedures conceming regeneration of plants from protoplasts of selected tomato cultivars are actually under investigation. Bogani et al (1995) using tomato cell clones, have ascertained influence of exogenous phytohormone treatment on DNA amplification and DNA methylation level changes -major factors in the determination of epigenetic changes, what was later confirmed in the same laboratory with RAPD analysis (Bogani et al 1996 (Lobenstein 1972, Walkey 1978. Somaclonal variation, an established method for increasing variation in plant cultivars, seems also to provide here a very promising strategy.…”

Somaclonal Variation and Induced Mutations in Crop Improvement

“…Somatic embryo plants have generally been less variable, and that indicated the maintenance of genetic fidelity; however, so-mac10nal variation could be observed when somatic embryo cultures were kept for a longer time in in-vitra conditions (Henry et al, 1997). Bogani et al (1995Bogani et al ( , 1996 analysed genetic variation with RAPDs in tomato long-term cultures grown on media containing different auxinlcytokynin equilibria. Thus, subcloning in Haworthia (Ogihara, 1990), an increase in the number of propagation cycles in Begonia (Westerhof et al, 1984), and ageing of Begonia (CasseIls and Morrish, 1987) and Pelargonium cultures , all increased chromosomal and/or phenotypic variation among regenerated plants (Table 8).…”