Poster: Late and Moved Abstracts
Abs #
1034: Genomic approaches to resistance to soybean cyst nematode populations
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Presenter: |
Kazi, Samreen , samreenk@siu.edu | Authors | Kazi, Samreen (A) Iqbal, Javed (A) Afzal, Jawad (A) Shopinski, Kay (A) Ahsan, Rubina (A) Triwitayakorn, Kanokporn (B) Jamai, Aziz (C) Shultz, Jeff (A) Meksem, Khalid (A) Arelli, Prakash (D) Bond, Jason (A) Lightfoot, David (A) | | Affiliations: |
(A): Southern. Illinois University, Carbondale, IL 62901.USA
(B): Mahidol University, Nakhon Pathom 73170, Thailand
(C): Dartmouth College, CT, USA
(D): USDA Tennessee
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| Web Site: | http://soybeangenome.siu.edu/ | |
Soybean cyst nematode (SCN; Heterodera glycines I) has many biotypes (~128) each with unique pathological potential. Understanding of how soybean resists SCN is limited. Resistance requires 2-5 genes depending on biotype and is temperature sensitive. Gene sequences provide clues after positional cloning of Rhg1 and Rhg4 (for resistance to soybean cyst nematode). Rhg1 and 4 are paralogs representing receptor like kinases. A membrane bound enzyme related to a variant laccase with unusual substrate requirements is also involved in resistance. RHG proteins appear to form temperature sensitive hetero- and homo-dimers. We hypothesize that Rhg, Rhg3 and Rhg5 are paralogs of known Rhg-genes. The aim of this study was to identify DNA markers and physical map contiguous overlapping sets of clones (contigs) linked closely to these genes. For this analysis a recombinant inbred line population ‘Flyer’ by ‘Hartwig’ and a BAC library from ‘Forrest’ provided genetic resources. Phenotype scores used biotypes 136 and 135678. Microsatellites identify loci as follows; Satt194 anchored neighboring contigs 8233, 3622 and 3802 (linkage group C1, Rhg5); Satt431 anchored contig 9289 (linkage group J, Rhg2); Satt486 to Satt498 currently anchor no contigs (linkage group D2, Rhg3). We have developed markers from linked sequences preparing for positional cloning of Rhg5 and Rhg3. Using the physical map and BAC library the remaining genes will be isolated by gene screens and sequencing of gene rich islands. Combining genome sequencing and substitution maps will annotate and isolate the set of Rhg genes efficiently. Gene interaction analysis will explain the molecular basis of biotype recognition and temperature sensitivity. This work was supported by NSF project #9872635, ISPOB 03-127 and USB3317.
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