Histopathological evidences of early grapevine leaf senescence caused by Phakopsora euvitis colonisation

Publication date: Available online 5 August 2019Source: Physiological and Molecular Plant PathologyAuthor(s): J.B. Rasera, L. Amorim, J.P.R. Marques, M.K.M. Soares, B. Appezzato-da-GlóriaAbstractGrapevine rust, caused by Phakopsora euvitis, has recently been introduced in Brazil; however, this disease has spread nationwide, causing significant damage to vineyards. The pathogen reduces CO2 assimilation and photoassimilate availability in host plants. Grapevine rust causes early defoliation and yield reduction, in the subsequent crop, since storage of reserves is compromised. Infection, colonisation and defoliation processes caused by the pathogen are not completely understood. In order to shed light on monocyclic components of grapevine rust, we have carried out histopathological analyses of the interaction between Phakopsora euvitis and leaves of Vitis labrusca ‘Niagara Rosada’. Fully expanded leaves of grapevines were inoculated with a suspension of 105 urediniospores mL−1 of P. euvitis, and collected at 1, 2, 4, 8 and 22 days after inoculation. The samples were fixed and processed for analysis under light, scanning and transmission electron microscopy. Ultrastructural analyses indicated that the pathogen forms appressoria on the stomata and ordinary epidermal cells within 24 h of inoculation. Epidermal cells of the mature leaf did not present pre- or post-formed defense mechanisms to penetration of Phakopsora euvitis. However, mesophyll cells, when infected, produc...
Source: Physiological and Molecular Plant Pathology - Category: Molecular Biology Source Type: research