Résumé
The nematode-plant interactions, as physiological processes of this parasitism and the Coffea canephora genes involved in the resistance to Meloidogyneparanaensis, are still poorly understood. Previous work reported that the drought-tolerant "clone 14" of C. canephora conilon was resistant to six different populations of root-knot nematodes, while the drought-sensitive "clone 22" was susceptible to nematode infections (Lima et al., 2015). Rationale. The objectives of the present study were to analyze the expression profiles of candidate genes putatively involved in nematode resistance in roots of clones 14 and 22 infected by nematodes. Methods. Total RNAs from roots of clones 14 and 22 were extracted at six different days after inoculation with M. paranaensis, converted in cDNAs and used in RT-qPCR experiments to check the gene expression profiles of the Cc00_g16260 and Cc10_g14530 genes of unknown function, CcCPI1(Cc03_g09540) coding for a cysteine protease inhibitor, and Cc01_g13400 coding a protein phosphatase (PP2C) putatively involved in the abscisic acid (AVA) signalization pathway. Results. The results were standardized using the constitutive expression of the CcUBQ10 gene coding for ubiquitin. For the genes Cc00_g16260, Cc10_g14530 and CcCPI1, expression profiles were up-regulated by nematode infection and higher in roots of clone 14 than in those of clone 22. Regarding the PP2C-encoding gene, expression decreased in roots of clone 22 inoculated by M. paranaensis but increased upon infection in those of clone 14. Conclusions and perspectives. Our results support the idea that no hits, CPI1 and also ABA pathway are involved (directly or indirectly) in the responses of the drought-tolerant clone 14 of C. canephora conilon to M. paranaensis infection. Our results also suggest that "cross-talks" between biotic and abiotic signaling pathways occured specifically in this coffee clone. (Texte intégral)