A quantitative trait locus of Agaricus bisporus resistance to Pseudomonas tolaasii is closely linked to natural cap color

A quantitative trait locus (QTL) of resistance to Pseudomonas tolaasii was detected in Agaricus bisporus using a cross between a wild strain from the Sonoran desert and a cultivated strain, The resistance QTL was strongly lin ked with the brown color allele of PPC1. This QTL explained about 30% of th e variation observed for living bacteria-induced symptoms. The use of bacte rial toxin did not reproduce living bacteria symptoms but revealed the same QTL. The latter QTL was not affected by environmental variation. No relati on was found between the resistance QTL and the tyrosinase gene, which is i nvolved in the browning process. (C) 1999 Academic Press.