Title : Analysis of metabolites modulated by Plasmopara viticola infection in Bianca grapevine leaves.
Abstract:
Downy mildew is one of the most destructive disease of grapevine caused by the biotrophic oomycete Plasmopara viticola in particular for the cultivated species Vitis vinifera. Due to their levels of resistance, grape from North America have been crossed with Vitis vinifera to introgress resistance. The use of grapevine varieties showing durable resistance to downy mildew is a promising strategy to control the disease. Grapevine-Plasmopara viticola interaction is still poorly understood from metabolic point of view therefore applying metabolomic approach can extended the up to date knowledge how the plant system is perturbed after stress and let us known which are the metabolites more affected after perturbation probably involved in resistance mechanisms. In this work we evaluated metabolic perturbation in the hybrid grape leaf discs after artificial infection with a suspension of Plasmopara viticola. In particular we investigated primary and secondary metabolism at 12, 24, 48 and 96 hours post infection (hpi) using methods of identification and quantification for lipid (LC-MS/MS), phenols (LC-MS/MS), primary compounds from acids, aminoacids, amines/others, sugars (GC-MS), semiquantification for volatiles compounds (GC-MS). This work offers some important information in the study of grapevine Plasmopara viticola interaction. A general principal component analysis shows a high variance on the first dimension explaining a separation according to the sampling time. Focusing on each class of compounds we found changes during the first 24-48 hpi regarding the primary metabolism in response to the pathogen infection with a modulation of some metabolites belonging from lipids, aminoacids, acids and sugars. Afterwards the secondary metabolism was affect more strongly by the pathogen with a changes of volatile compounds at 48-96 hpi. The classes of compounds more affected after the infection turns out to be phenylpropanoids, flavonols, stilbenes and stilbenoids at 96 hpi. Our results gave a picture of plant metabolome perturbation and it is up to our knowledge the first time that an extensive metabolites study using a hybrid grape variety has been done to better understand the metabolomics perturbation after Plasmopara viticola infection.
