Molecular markers located proximal to the soybean cyst nematode resistance gene, Rhg4

Probe pBLT24 is a cDNA encoding a 34 kDa soybean seed protein with sequence homology to thiol proteases of the papain family. Probe pBLT65 was isolated from a lambda gt11 cDNA library screened with a carrot cDNA encoding aspartokinase-homoserine dehydrogenase. The two probes used in this study were maintained as inserts in E. coli plasmid vectors. Plasmid DNA was digested with a restriction endonuclease to release the insert. DNA fragments were purified on agarose gels. The DNA fragments to be use as probes were radiolabeled using the random oligonucleotides labeling procedure of Feinberg and Vogelstein.