Phenotypical and gene expression analyses of Rfo-sa1 resistant eggplant interaction with Fusarium oxysporum f. sp. melongenae and Verticillium dahliae. Solanum virginianum

Eggplant is susceptible to fungal wilts caused by Fusarium oxysporum f. sp. melongenae and Verticillium dahliae. Wild relatives represent a good source of resistance and ILs have been obtained through introgression of the Rfo-sa1 locus conferring resistance to Fusarium oxysporum from the allied species S. aethiopicum into cultivated eggplant. In this work, a deep phenotypical characterization was performed according to the progression of symptoms along the stem and the disease severity in leaves. This analysis showed that the Fom -resistant ILs carrying introgression of the Rfo-sa1 locus displayed significantly improved tolerance to Verticillium attack after a preliminary inoculation with F. oxysporum. This positive effect was particularly evident when Verticillium inoculation was done simultaneously or after the Fusarium one. Transcript profiling carried out using a combination of SSH, microarray and qRT-PCR analyses from inoculated roots with a selected combinations of fungal pathogens enabled the identification of 164? differentially expressed genes at least in one condition. Overall, our results highlighted a number of candidate genes putatively involved in early defence responses or signalling pathways activated upon infection of eggplant either with Fom and Vd and thus leading to a broad Rfo-sa1 mediated tolerance against both these wilt pathogens. Overall design: S. melongena roots mock inoculated, Fusarium oxysporum f. sp. Melongenae inoculated, Verticillium dahlie inoculated and inculated by both Fusarium and Verticillium have been collected in biological triplicate at 0, 4 and 8 hours post infection to evaluate expression levels with an array contructed from ESTs and RAD tags