Valine-Resistance, a Potential Marker in Plant Cell Genetics. II. Optimization of Uv Mutagenesis and Selection of Valine-Resistant Colonies Derived from Tobacco Mesophyll Protoplasts.

摘要: ABSTRACT The induction and selection of valine-resistant mutants from haploid tobacco ( Nicotiana tabacum L.) mesophyll protoplast-derived cells have been studied. Using an original mutant plant obtained previously, we performed reconstruction experiments in order to determine the best conditions for recovery resistant among a population sensitive cells. Optimal selective were shown depend on various factors including cell density, time addition valine seasonal variations affecting mother plants.—Using densities approximately 10 4 cells/ml, defined efficient conditions: more than 25% putative clones selected UV-mutagenized protoplasts reproducibly confirmed be resistant. Further characterization some regenerated plants indicated that valine-resistance was associated with uptake deficiency, as case Val r -2 line used experiments. Spontaneous mutation rates below accurately detectable levels, i.e. , less -6 per generation. Induced frequency varied nonlinearily UV dose -5 5 × -4 surviving colony. Two independent loci vr2 vr3 ) previously involved due amino acid deficiency. Haploid produced through anther culture F 1 double-heterozygous cross between wild-type plant. Study level resistance allowed classification these four types: sensitive, two intermediary types believed result presence allele at only one involved. frequencies UV-induced mutations derived compared those observed results are considered light amphidiploid structure genome.