Specific protease activities induced in the apoplast of a resistant tomato cultivar in response to Ralstonia solanacearum infection
N. COLL (1), M. Planas-Marquès (1), J. Paulus (2), F. Kaschani (3), R. van der Hoorn (2), M. Valls (1) (1) Centre for Research in Agricultural Genomics, Spain; (2) Plant Chemetics Laboratory, Department of Plant Sciences, University of Oxford, United Kingdom; (3) Chemical Proteomics, Fakultät für Biologie, Zentrum für Medizinische Biotechnologie, Universität Duisburg-Essen, Germany

Ralstonia solanacearum is a soil-borne pathogen that causes the widespread devastating disease known as bacterial wilt. The most effective way to fight the disease seems to be the use of resistant cultivars, but little is known about the molecular mechanisms that confer resistance to R. solanacearum. The first interaction between R. solanacearum and its hosts takes place in the apoplast, but few works have focused on analyzing the protease dynamic changes that occur in this location upon infection. In this work, we characterized the response generated in the apoplast of a susceptible (Marmande) and resistant (Hawaii7996) varieties of tomato (Solanum lycopersicum) when challenged with R. solanacearum. Vacuum-infiltration of Marmande leaves resulted in wilting symptoms from day 3 after inoculation. However, Hawaii7996 plants are able to tolerate better the infection, showing less disease symptoms. The apoplast of infiltrated leaves was collected two days after inoculation, and induction of protein activity was analyzed by activity-based protein profiling coupled with mass spectrometry. Analyses of the identified proteins indicate that tomato papain-like cysteine proteases and serine hydrolases were induced in the presence of R. solanacearum, and the intensity of these responses was enhanced in the resistant cultivar. To our knowledge, this is the first time that an induction of apoplastic protease activities is defined in the context of R.solanacearum-tomato interaction.

Abstract Number: P6-139
Session Type: Poster