ARS | Publication request: GENETIC MAPPING OF THE PC GENE IN SORGHUM

Submitted to: Plant Genome Analysis Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: December 1, 1997
Publication Date: N/A

Technical Abstract: The Pc gene in sorghum controls susceptibility to the root rot fungus Periconia circinata and response to peritoxin, a host-selective toxin produced by pathogenic strains. Disease susceptibility is strictly correlated with sensitivity to peritoxin, which reproduces disease symptoms. To understand the molecular mechanisms controlling the sorghum-Periconia interaction, our goal is to clone and characterize the Pc gene. To find DNA markers tightly linked to Pc, we analyzed bulked DNA pools from susceptible (PcPc; toxin sensitive) or resistant (pcpc; toxin insensitive) F2's of the cross susceptible (S) 'Colby' (PcPc) x 'Shanqui Red' (pcpc). Five random amplified polymorphic DNA (RAPD) markers were identified in a screen of 1600 arbitrary primers. Two of those markers co-segregated with the susceptible phenotype (in coupling) and three with the resistant phenotype (in repulsion). Sequence-tagged-site (STS) primers concerted from these RAPD markers were designed and used to screen the same F2 population and the recombinant inbred (RI) lines derived from the cross of SRN39 x Shanqui Red. The STSB12 and STS010 markers were closely linked to Pc, 7.9 cM and 5.9 cM, respectively. Four maize clones flanking STS010 on sorghum linkage group I were chosen for RFLP analysis. UIU101 was found to be tightly linked (0.98 cM) to Pc when 51 homozygous susceptible F3 families of S-Colby X Shanqui Red were analyzed; the other clones were not polymorphic in the RI lines. For high resolution mapping, UIU101 was mapped to chromosome 6 of maize, which contains markers colinear with sorghum linkage I.