MITOCHONDRIAL-DNA VARIATION IN SOMATIC EMBRYOGENIC CULTURES OF LARIX

Southern hybridization analysis using wheat mitochondrial gene-specific probes indicates that changes in mitochondrial genomic organization and the relative representation of certain genomic regions occur during in vitro somatic embryogenic cell culture of Larix species. We observed differences in the mitochondrial (mt)DNA hybridization patterns between somatic embryogenic cell cultures and trees grown from seed for Larix leptolepis, L. decidua, and the reciprocal hybrids of these two Larix species. This is the first study to describe the correlation of molecular changes in a gymnosperm mitochondrial genome with in vitro somatic embryogenic cell culture. Quantitative differences in mtDNA hybridization signals were also observed among a 4-year-old somatic embryogenic cell culture of Larix x eurolepis trees regenerated from this culture, and the seed source tree from which the somatic embryogenic cell cultures were initiated.