Diniz I. auteur aut IRD Talhinhas P. auteur aut IRD Azinheira H. G. auteur aut IRD Varzea V. auteur aut IRD Medeira C. auteur aut IRD Maia I. auteur aut IRD Petitot Anne-Sophie auteur aut IRD Nicole Michel auteur aut IRD Fernandez Diana auteur aut IRD Do Ceu Silva M. auteur aut IRD text journalArticle eng text/pdf born digital access In Arabica coffee breeding, some of the most used sources of resistance to leaf rust (Hemileia vastatrix) are natural Coffea arabica x canephora hybrids ("Hibrido de Timor"). To decipher the cellular and molecular nature of that resistance, leaves of genotype HDT832/2, were challenged with H. vastatrix race II, and monitored using light microscopy and RT-qPCR expression analysis of genes involved in plant immunity mechanisms (receptor-like kinase, WRKY transcription factor 1, phenylalanine ammonia-lyase, chalcone synthase, 13-lipoxygenase, glycosyltransferase, pathogenesis related PR1b and PR10). These were compared to the nonhost resistance responses of HDT832/2 to the infection by the cowpea rust fungus (Uromyces vignae). H. vastatrix ceased growth more frequently after stomata penetration, forming few haustoria, inducing a hypersensitive-like response, phenol accumulation and haustorium encasement with callose. U. vignae could enter stomata but failed to form haustoria, while inducing hypersensitive-like responses and phenol accumulation. In host and nonhost interactions, activation of genes involved in signalling coincided with the differentiation of appressoria, and cellular responses (hypersensitive-like responses and accumulation of phenolic compounds) were recorded from the full appressorium or penetration hypha stages onwards. Similarly, a gene related to the JA pathway was first activated at the penetration hypha stage for both interactions, while genes related to the SA pathway were only activated in the host interaction, the latter being the single clear difference between host and nonhost interactions. The cellular and molecular resistance responses of HDT832/2 to these rust fungi suggest that common immunity components are shared between host and nonhost resistance, which may explain the longer durability of this resistance. specialized Basal immunity Coffea arabica Coffea canephora Coffee leaf rust Defence gene expression Hypersensitive response 076 133 1 141-157 2012 0929-1873 https://www.documentation.ird.fr/hor/fdi:010055823 10.1007/s10658-011-9925-9 0929-1873 [F B010055823] https://www.documentation.ird.fr/hor/fdi:010055823 https://www.documentation.ird.fr/intranet/publi/2012/05/010055823.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2012-06-01 2017-08-23 fdi:010055823 fre