RFLP, RAPD, and lectin-binding glycoprotein analyses of downy mildew, head smut, and acremonium wilt resistance in sorghum

Vita.The objective of RFLP and RADP analyses was to find molecular markers linked to resistance genes for downy mildew, head smut, and acremonium wilt of sorghum. The Sdm locus controls resistance to downy mildew caused by Peronosclerospora sorghi in sorghum (Sorghum bicolor). RFLP analysis placed the Sd m locus in the interval between marker loci detected by probes pSbTXS3 61 and pSbTXS552 at 6.6 and 6.1 cMs, respectively, in accession SC325. The Shs locus controls resistance to head smut caused by Sporisorium reilianum in sorghum. RFLP and RAPD analyses revealed that two RFLP loci detected by probes pSbTXS560 and pSbTXSl294, and one RAPD locus from primer 0PG5 were linked to Shs in accession SC325. The a w locus controls resistance to acremonium wilt caused by Acremonium strictum in sorghum. By linkage analysis, one RFLP locus detected by probe pSbTXS1225 is linked to the a w locus in IS3620C at 19.4 cMs. The a w locus and txsl225 are located at the end of linkage group J of the sorghum RFLP map. Glycoprotein changes following developmental transition were detected in the meristematic tissue of sorghum head smut reaction classes (Rl, R2, R 3 , and Si) after sodium dodecyl sulfate-gel electrophoresis and protein blotting by six biotinylated lectins (BS-I, Con A, PNA, SBA, UEA I, and WGA). A screening using biotinylated lectins indicated that BS-I, PNA, and SBA bound to glycoproteins containing a-D-gal, p-D-gal(1-3)-D-galNAc, and D-galNAc only from the vegetative meristem. Conversely, Con A bound to glycoproteins containing a-D-glc and a-Dman only from the reproductive meristem. These BS-I, PNA, SBA, and Con A-binding specificities did not show any differences among Rl, R2, R3, and SI. UEA I (a-L-fuc) binding specificity was detected at Rl, R2, R3, and Si in vegetative meristems, but only at R2 and R3 in reproductive meristems. WGA (p-D-glcNAc) binding specificity was not detected in all vegetative and reproductive meristems