Cytological characterization of transgenic soybean
1998
Singh, R.J. | Klein, T.M. | Mauvais, C.J. | Knowlton, S. | Hymowitz, T. | Kostow, C.M.
Some of the transgenic soybean [Glycine max (L.) Merr.] plants produced by bombarding embryogenic suspension cultures with DNA-coated particles exhibit morphological aberrations, including stunted plant growth, leathery dark green leaves toand partial-to-total seed sterility. In general cultures from two Asgrow soybean lines (A2242, A2872) maintained for 8 months or longer produced primary transformants with reduced ferlility. Cytological examination (mitotic pro-metaphase to metaphase chromosomes) of cells of suspension cultures, of germinating somatic embryos, and of plants (R0 and R1) derived from A2242, revealed, besides (2n = 40), various chromosomal aberrations deletions, duplications, trisomics and tetraploidy. Diploid transgenic plants with a normal karyotype from A2242 generally exhibited good fertility. No chromosomal abnormalities were observed in A2872-derived plants. However, plants regenerated from relatively old cultures of A2872 (more than 1 year in culture) showed a range of phenotypic abnormalities although they all contained 2n = 40 chromosomes. These results indicate that soybean genotypes differ in their susceptibility to chromosomal instability induced by tissue culture. Therefore, chromosome analysis of cell cultures and the plants derived from them can help eliminate chromosomally and genetically abnormal material from gene-transfer experiments.
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