Segregation distortion of T-DNA markers linked to the self-incompatibility (S) locus in Petunia hybrida.
In plants with a gametophytic self-incompatibility system the specificity of the pollen is determined by the haploid genotype at the self-incompatibility (S) locus. In certain crosses this can lead to the exclusion of half the gametes from the male parent carrying a particular S-allele. This leads to pronounced segregation distortion for any genetic markers that are linked to the S-locus. We have used this approach to identify T-DNA insertions carrying a maize transposable element that are linked to the S-locus of Petunia hybrida. A total of 83 T-DNA insertions were tested for segregation distortion of the selectable marker used during transformation with Agrobacterium. Segregation distortion was observed for 12 T-DNA insertions and at least 8 of these were shown to be in the same linkage group by intercrossing. This indicates that differential transmission of a single locus (S) is probably responsible for all of these examples of T-DNA segregation distortion. The identification of selectable markers in coupling with a functional S-allele will allow the preselection of recombination events around the S-locus in petunia. Our approach provides a general method for identifying transgenes that are linked to gametophytic self-incompatibility loci and provides an opportunity for transposon tagging of the petunia S-locus.
Harbord
R M
RM
Sainsbury Laboratory, John Innes Centre, Norwich NR4 7UH, United Kingdom.
Napoli
C A
CA
Robbins
T P
TP
D003433:Crosses, Genetic; D004269:DNA, Bacterial; D018744:DNA, Plant; D008040:Genetic Linkage; D005819:Genetic Markers; D008540:Meiosis; D019657:Solanaceae / Q000235:genetics*
D004269:DNA, Bacterial; D018744:DNA, Plant; D005819:Genetic Markers; C036483:T-DNA