Isolation of nutritional mutants in Arabidopsis thaliana.

Abstract

An accumulation method was devised for the isolation of nutritional mutants of the CruciferArabidopsis thaliana. Six mutants were obtained, in all of which the synthesis of thiamine was blocked. The mutants showed chlorophyll deficiencies and were more or less depressed in growth. Thiamine, when added to the substrate, fully restored normal development. Three of the mutants also grew on a substrate containing the pyrimidine moiety of the vitamin molecule, one on a medium with the thiazole part, one on a substrate containing a mixture of both compounds, whereas the sixth mutant required the complete thiamine molecule for normal growth. Two of the three “pyrimidine”-less mutants were allelic, the third, when crossed with each of the other two, yielded F1's showing wild type growth in their youth but deficiency symptoms in later stages. In each of the other mutants different loci were involved. The relation between the method employed and the type of mutant isolated is discussed.