Identification of a 1-aminocyclopropane-1-carboxylic acid synthase gene linked to the female (F) locus that enhances female sex expression in cucumber.
Sex determination in cucumber (Cucumis sativus L.) is controlled largely by three genes: F, m, and a. The F and m loci interact to produce monoecious (M_f_) or gynoecious (M_f_) sex phenotypes. Ethylene and factors that induce ethylene biosynthesis, such as 1-aminocyclopropane-1-carboxylate (ACC) and auxin, also enhance female sex expression. A genomic sequence (CS-ACS1) encoding ACC synthase was amplified from genomic DNA by a polymerase chain reaction using degenerate oligonucleotide primers. Expression of CS-ACS1 is induced by auxin, but not by ACC, in wounded and intact shoot apices. Southern blo hybridization analysis of near-isogenic gynoecious (MMFF) and monoecious (MMff) lines derived from divers genetic backgrounds revealed the existence of an additional ACC synthase (CS-ACS1G) genomic sequence in the gynoecious lines. Sex phenotype analysis of a segregating F2 population detected a 100% correlation between the CS-ACS1G marker and the presence of the F locus. The CS-ACS1G gene is located in linkage group B coincident with the F locus, and in the population tested there was no recombination between the CS-ACS1G gene and the F locus. Collectively, these data suggest that CS-ACS1G is closely linked to the F locus and may play a pivotal role in the determination of sex in cucumber flowers.
Trebitsh
T
T
Section of Plant Biology, University of California, Davis 95616, USA.
Staub
J E
JE
O'Neill
S D
SD
D015139:Blotting, Southern; D018553:Cucumis sativus / Q000201:enzymology / Q000235:genetics*; D008040:Genetic Linkage; D005819:Genetic Markers; D008190:Lyases / Q000235:genetics*; D008969:Molecular Sequence Data; D012733:Sex Differentiation / Q000235:genetics
D005819:Genetic Markers; D008190:Lyases; C021773:1-aminocyclopropanecarboxylate synthase