Trunk anatomy of asymptomatic and symptomatic grapevines provides insights into degradation patterns of wood tissues caused by Esca-associated pathogens

Wood colonizing fungi are specialists that exploit the lignocellulose of cell wall components in host wood cylinders as a carbon sources. Some these specialized fungi, including Fomitiporia mediterranea (Fmed) and Phaeomoniella chlamydospora (Pch), cause disease Esca grapevine. This complex includes grapevine leaf stripe (GLSD) canopies white rot black streaking trunks. The present study gained insights into activity pathogens xylem trunk tissues at an anatomical level. Lesions with brown were microscopically analyzed, structures affected compared intact xylem. In trunks rot, demarcation zones separated from lesions. Immediately adjacent to zones, decomposition initiated At this initial stage, cavities appeared secondary walls libriform fibres, which expanded closely resembled degradation pattern soft rot. advanced fibre completely decomposed, vessels attacked similar Only remnants elements remained, forming amorphous matrices. These patterns occurred field samples cores artificially infected Fmed. obvious compartmentalization tissue by Fmed indicated defense reaction xylem, according CODIT model. contrast, only small groups vessels, fibres parenchyma. Dark inclusions cells tyloses indicate against causing streaking. Artificial inoculation sterile Pch confirmed contribution pathogen research provides structural functional anatomy grapevines, clarify etiology Esca, provide new knowledge for developing approaches control complex.