LAUSR

Subtilases (SBTs) are serine peptidases with a diverse array of functions from development to environment interactions. In the last decade, plant subtilases have been widely associated to plant defence mechanisms against the most diverse pathogens. Recently, we have characterized the grapevine (Vitis vinifera L.) SBT gene family, and identified 87 genes encoding for 109 predicted proteins, phylogenetically divided into 5 groups and several predicted to be glycosylated and located in the apoplast. One specific grapevine SBT, VviSBT4.19, is highly regulated after challenge by the downy mildew causing agent, Plasmopara viticola. This subtilase may be involved in immune priming events leading to the incompatible grapevine-P. viticola interaction. Aiming at structure, substrates and interacting partners identification, we have clone VviSBT4.19 open reading frame and expressed the recombinant protein in both prokaryotic and eukaryotic systems. The eukaryotic model, Tobacco BY2 cells, normally used for complex proteins expression, revealed to be the most suitable system. At the present we are producing VviSBT4.19 recombinant protein. Native mass spectrometry, crystallography, substrate identification and interactome analysis will be used to fully access its action mechanism.