Plant Genome I Conference
Town & Country Conference Center, San Diego, CA, November, 1992.
PG-I: 54pg1
MAPPING AND TAGGING HOST GENES INVOLVED IN LEGUME/MICROBE
INTERACTIONS.
N. Weeden 1, J. Lu 1, S. Temnykh 1, G. Timmerman 2, C. Simon 3,
B. Kneen 1, R. Provvidenti 4, F. Muehlbauer 3, and T. LaRue 5, 1
Dept. of Hort. Sci. and 4 Dept of Plant Path, Cornell Univ,
Geneva NY, 2 New Zealand Institute for Crop & Food Research
Ltd, Lincoln, New Zealand, 3 USDA/ARS, 215 Johnson Hall,
Pullman, WA, 99164, and 5 Boyce Thompson Institute, Ithaca,
NY 14853
Genes involved in disease resistance and nitrogen fixation
are being mapped in several legume species to examine their
distribution, homology, and mechanism of action. A relatively
saturated linkage map is available for pea, and conserved linkage
groups comprising about 40% of the pea map have been identified
in lentil and chickpea. Over 20 genes or gene families directly
affecting modulation phenotype have been mapped in pea. Several
of these genes cluster in a small region on chromosome 1, and we
have identified numerous RAPD markers in this region. Lectins
have been implicated in host/Rhizobium recognition. At least two
mutants have been identified that alter pea/Rhizobium strain
specificity, but neither appears to be a result of changes in the
lectin genes. Tags for nine genes conferring virus resistance
as well as a gene conferring resistance to powdery mildew have
been dentified in pea. Some of these genes are located in
linkage groups conserved in lentil and chickpea. Should similar
resistance genes in lentil be mapped to the corresponding linkage
group, it would strongly suggest that the two genes are
homologous. Conversely, if the resistance gene in lentil maps to
a different linkage group, we would tentatively assume the two
genes are not homologous and may act through different
mechanisms.
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