We have constructed a transformation-competent, Arabidopsis ecotype Columbia strain GH50 nuclear genomic library in Agrobacterium host strain AGL1 and cosmid vector pLZO3, both specially engineered for these purposes. This genomic library comprises some 22,000 random clones gridded onto 225 96-well microtiter dishes and, if random, carries some five Arabidopsis genomic equivalents. Arabidopsis strain GH50 carries a dominant acetolactate synthase (als) allele conferring chlorsulfuron resistance. We shall develop high efficiency Arabidopsis whole-plant DNA transformation of newly germinated seedlings as a tool for gene rescue. By a "successive approximation" method, we shall conduct seedling transformation so as to be able to infer individual clones in the genomic library giving rise to transformants. We shall use the transformation- competent Arabidopsis GH50 genomic library constructed in Agrobacterium to rescue the ahs1-1 allele conferring resistance to the sulfonylurea herbicide chlorsulfuron. If successfully developed, this technology will allow the expeditions isolation of genes central to plant growth and development. This gene rescue technology will allow us to efficiency integrate Arabidopsis physical genomic and genetic maps.***//
