Cell wall glycan architecture as a determinant of pinewood nematode host susceptibility
Ricardo M. F. da Costa (Portugal)1 2; Luís B. Fonseca (Portugal)2 3; Maria João Ferreira (Portugal)4; Miguel Moreira (Portugal)4; Martin Vojtek (Portugal)5; Ieva Lelenaite (UK)6; Joana Cardoso (Portugal)2 7; Carmen Diniz (Portugal)5; Luís Batista de Carvalho (Portugal)1; Jorge M. P. L. Canhoto (Portugal)2; William G. T. Willats (UK)6; Sílvia Coimbra (Portugal)4;
1 - LAQV-REQUIMTE, Molecular Physical-Chemistry R&D Unit, Department of Chemistry, University of Coimbra, Coimbra, Portugal; 2 - Centre for Functional Ecology (CFE), Associate Laboratory TERRA, Department of Life Sciences, University of Coimbra, Coimbra, Portugal; 3 - FITOLAB – Laboratory for Phytopathology, Instituto Pedro Nunes (IPN), Coimbra, Portugal; 4 - LAQV-REQUIMTE, Biology Department, Faculty of Sciences, University of Porto, Porto, Portugal; 5 - LAQV-REQUIMTE, Laboratory of Pharmacology, Department of Drug Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal; 6 - School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom; 7 - INIAV, I.P., National Institute for Agrarian and Veterinary Research, Oeiras, Portugal;
Keywords: Pine wilt disease; Glycome; Pinewood nematode secretome;
Abstract Topics: Theme 9: Cell Wall Function and Signaling in plant adaptation to Biotic and Abiotic Stresses
Type of Presentation: Poster

Abstract text: The pinewood nematode (PWN), Bursaphelenchus xylophilus, uses its stylet to pierce plant cell-walls (CW) while releasing carbohydrate-active enzymes (CAZymes). We hypothesise CW chemistry and architecture dictate host susceptibility to pine wilt disease (PWD). Here we summarise ongoing work from the PineWALL project, comparing Pinus pinaster (PWN-susceptible), Pinus pinea (resistant) and Pinus halepensis (intermediate) under artificial inoculation and controlled environmental conditions. Presently, we focus on the CW carbohydrate fraction, combining Fourier-Transform Infrared Spectroscopy (FTIR), monosaccharide profiling by High-Performance Anion-Exchange Chromatography (HPAEC), immunohistochemistry and Microarray Polymer Profiling (MAPP) with monoclonal antibodies to key CW epitopes. Our data indicate a tendency towards higher mannose and stronger mannan-epitope signals in PWN-resistant pines, whereas the susceptible species shows higher xylose and galactose and higher signals for xyloglucan and rhamnogalacturonan-I (RG-I)-related epitopes. Within susceptible P. pinaster, inoculated versus non-inoculated plants show shifts in arabinogalactan proteins (AGP)-associated epitopes which may be infection-linked. We propose that these differences in matrix-glycan architecture shape the substrate landscape encountered by PWN upon infection, influencing host defence capacity. Further insight will emerge from reanalysing our PWN secretome dataset (Cardoso et al., 2016, https://doi.org/10.1038/srep39007), to annotate secreted CAZymes and assess enzyme-substrate matching in light of the novel pine CW data generated here.