Bean-Colletotrichum lindemuthianum Compatible Interactions: Time Course of Plant Defense Responses Depends on Race. Aline Mahé. Laboratoire de Phytopathologie Moléculaire, Départment de Biologie Moléculaire Végétale, Bâtiment 430, Université Paris Sud, 91405 Orsay Cedex, France. Jeanine Grisvard, Thierry Desnos, and Michel Dron. Laboratoire de Phytopathologie Moléculaire, Départment de Biologie Moléculaire Végétale, Bâtiment 430, Université Paris Sud, 91405 Orsay Cedex, France.. MPMI 5:472-478. Accepted 3 August 1992. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1992.

We investigated different compatible race-cultivar interactions between Colletotrichum lindemuthianum and bean to understand the role of the pathogen and the plant genetic background on the expression of symptoms, infection processes, and transcriptional activation of plant defense genes. Different races of C. lindemuthianum (1, 2, and 9) were used to inoculate one bean cultivar (P₁₂S). Races 1 and 2 displayed very similar patterns of pathogenicity (symptoms and infection process) and caused similar accumulations of four defense-related mRNAs (phenylalanine ammonia-lyase, chalcone isomerase, chitinase, and hydroxyproline-rich glycoprotein). In contrast, race 9 provoked symptoms more rapidly. This was correlated with a faster progression of the fungus and an earlier accumulation of the induced mRNA transcripts. No accumulation of the hydroxyproline-rich glycoprotein transcript was observed after infection with race 9. The interaction of two bean cultivars (P₁₂S and EyS) with race 2 was further investigated. The two cultivars exhibited very similar behaviors after inoculation with race 2.