IDENTIFICATION AND ISOLATION OF THE FEEBLY GENE FROM TOMATO BY TRANSPOSON TAGGING

The Ac/Ds transposon system from maize was used for insertional mutage nesis in tomato. Marker genes were employed for the selection of plant s carrying a total of 471 unique Ds elements. Three mutants were obtai ned with Ds insertions closely linked to recessive mutations: feebly ( fb), yellow jim (yj) and dopey (dp). The fb seedlings produced high an thocyanin levels, developed into small fragile plants, and were insens itive to the herbicide phosphinothricin. The yj plants had yellow leav es as a result of reduced levels of chlorophyll. The dp mutants comple tely or partially lacked inflorescences. The fb and yj loci were genet ically linked to the Ds donor site on chromosome 3. Reactivation of th e Ds element in the fb mutants by crosses with an Ac-containing line r esulted in restoration of the wild-type phenotypes. Plant DNA fragment s flanking both sides of the Ds element in the fb mutant were isolated by the inverse polymerase chain reaction. Molecular analysis showed t hat phenotypic reversions of fb were correlated with excisions of Ds. DNA sequence analysis of Fb reversion alleles showed the characteristi c Ds footprints. Northern and cDNA sequence analysis indicated that tr anscription of the FEEBLY (FB) gene was impeded by the insertion of Ds in an intron. Comparison of the predicted amino acid sequence of the FB protein with other database sequences indicated that FB is a novel gene.