Isolation of a new paramutagenic allele of the sulfurea locus in the tomato cultivar Moneymaker following in vitro culture
1993
Wisman, E. | Ramanna, M.S. | Koornneef, M.
A new allele, SC148, of the sulfurea locus in Lycopersicon esculentum was detected in a line derived after repeated selfing of plants that had been regenerated from tissue culture. Like the original sulf mutant, SC148 displayed two mutant phenotypes: green-yellow speckled plants in which the sulfvag allele is present and pure yellow plants homozygous for the sulfpura allele. Although the mutant alleles are recessive to wild-type, an unpredictable number of variegated and pura plants appeared in F1 progenies that had been derived from crosses between SC148 and wild-type tomato plants. The presence of the wild-type sulf+ allele in these variegated heterozygotes was demonstrated using a cytological marker that is linked to sulf. It is concluded that the mutant sulf allele of SC148, imposes its variegated expression state on the wild-type sulf+ allele present in sulf+/sulfvag heterozygotes. This behaviour, known as paramutation, has also been described for the original sulf allele. The SC148 allele, however, seems to induce changes at an earlier stage in development. The analogy of this paramutagenic system to dominant position effect variegation in Drosophila is discussed.
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