A proteomic study of in-root interactions between chickpea pathogens: the root-knot nematode Meloidogyne artiellia and the soil-borne fungus Fusarium oxysporum f. sp. ciceris race 5.

Fusarium wilt caused by the fungus Fusarium oxysporum f. sp. ciceris (Foc) is the main soil-borne disease limiting chickpea production. Management of this disease is achieved mainly by the use of resistant cultivars. However, co-infection of a Foc-resistant plant by the fungus and the root-knot nematode Meloidogyne artiellia (Ma) causes breakdown of the resistance and thus limits its efficacy in the control of Fusarium wilt. In this work we aimed to reveal key aspects of chickpea:Foc:Ma interactions, studying fungal- and nematode-induced changes in root proteins, using chickpea lines 'CA 336.14.3.0' and 'ICC 14216K' that show similar resistant (Foc race 5) and susceptible (Ma) responses to either pathogen alone but a differential response after co-infection with both pathogens. 'CA 336.14.3.0' and 'ICC 14216K' chickpea plants were challenged with Foc race 5 and Ma, either in single or in combined inoculations, and the root proteomes were analyzed by two-dimensional gel electrophoresis using three biological replicates. Pairwise comparisons of treatments indicated that 47 protein spots in 'CA 336.14.3.0' and 31 protein spots in 'ICC 14216K' underwent significant changes in intensity. The responsive protein spots tentatively identified by MALDI TOF-TOF MS (27 spots for 'CA 336.14.3.0' and 15 spots for 'ICC 14216K') indicated that same biological functions were involved in the responses of either chickpea line to Foc race 5 and Ma, although common as well as line-specific responsive proteins were found within the different biological functions. To the best of our knowledge, this is the first study at the root proteome level of chickpea response to a biotic stress imposed by single and joint infections by two major soil-borne pathogens.