BioProject

Background: Flavescence dorée is the most serious grapevine yellows disease in Europe. More...

Background: Flavescence dorée is the most serious grapevine yellows disease in Europe. It is caused byphytoplasmas which are transmitted from grapevine to grapevine by the leafhopper Scaphoideus titanus.Differences in susceptibility among grapevine varieties suggest the existence of specific genetic features associatedwith resistance to the phytoplasma and/or possibly with its vector. In this work, RNA-Seq was used to compareearly transcriptional changes occurring during the three-trophic interaction between the phytoplasma, its vectorand the grapevine, represented by two different cultivars, one very susceptible to the disease and the otherscarcely susceptible.Results: The comparative analysis of the constitutive transcriptomic profiles suggests the existence of passivedefense strategies against the insect and/or the phytoplasma in the scarcely-susceptible cultivar. Moreover, theattack by the infective vector on the scarcely-susceptible variety prompted immediate and substantialtranscriptomic changes that led to the rapid erection of further active defenses. On the other hand, in the mostsusceptible variety the response was delayed and mainly consisted of the induction of phytoalexin synthesis.Surprisingly, the jasmonic acid- and ethylene-mediated defense reactions, activated by the susceptible cultivarfollowing FD-free insect feeding, were not detected in the presence of the phytoplasma-infected vector.Conclusions: The comparison of the transcriptomic response in two grapevine varieties with different levels ofsusceptibility to Flavescence dorèe highlighted both passive and active defense mechanisms against the vector and/or the pathogen in the scarcely-susceptible variety, as well as the capacity of the phytoplasmas to repress thedefense reaction against the insect in the susceptible variety. Less...