Molecular markers residing close to the [Rhg.sub.4] locus conferring resistance to soybean cyst nematode race 3 on linkage group A of soybean

The restriction fragment length polymorphism (RFLP) clone pBLT65 is a 450-nt soybean cDNA encoding a portion of the bifunctional enzyme aspartokinase-homoserine dehydrogenase (AKHSDH). pBLT65 maps within 3.5 cM of the i locus, conferring a pigmented seed coat, on linkage group A; hence, it is closel...

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Published inTheoretical and applied genetics Vol. 97; no. 7; pp. 1047 - 1052
Main Authors Matthews, B.F, MacDonald, M.H, Gebhardt, J.S, Devine, T.E
Format Journal Article
LanguageEnglish
Published Springer 01.11.1998
Subjects
Biological markers
Chromosome mapping
Genetic aspects
Genetic polymorphisms
Identification and classification
Plant genetics
Plant immunology
Soybean
United States
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Summary:The restriction fragment length polymorphism (RFLP) clone pBLT65 is a 450-nt soybean cDNA encoding a portion of the bifunctional enzyme aspartokinase-homoserine dehydrogenase (AKHSDH). pBLT65 maps within 3.5 cM of the i locus, conferring a pigmented seed coat, on linkage group A; hence, it is closely linked to the [rhg.sub.4]locus conferring resistance to race 3 of the soybean cyst nematode. From this useful RFLP we developed a PCR reaction yielding polymorphic bands for use in marker-assisted breeding programs to select progeny containing the [rhg.sub.4]allele. The polymorphic bands were sequenced to determine the cause of the polymorphisms. Using primers 548 and 563, PCR amplification of DNA from the soybean cultivar Peking ([Rhg.sub.4]) yielded three DNA fragments, 1a (1160 bp), 1b (1146 bp) and 3 (996 bp). Amplification of DNA from the cultivar Kent ([rhg.sub.4]) yielded DNA fragments 2 (1020 bp), 3 (996 bp) and 4 (960 bp). Fragments 1a, 1b, 2 and 4 were also polymorphic between the soybean lines PI 290136 and BARC-2([Rj.sub.4]). A segregating population of 80 [F.sub.2] and [F.sub.3] plants derived from the cross PI 290136 x BARC-2 ([Rj.sub.4]) was used to confirm the map position of the PCR polymorphisms near the i locus, and hence the [rhg.sub.4] locus on linkage group A. The nucleotide sequences of fragments 1b, 3 and 4 were determined. Large and small deletions in the intronic region were responsible for the size differences of the different fragments, whereas the exon was well conserved.
ISSN:0040-5752
1432-2242