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Aggressiveness of Phakopsora: a comparative analysis of grapevine and soybean rusts with emphasis to histopathology and epidemiology

Grant number: 15/26108-8
Support type:Scholarships in Brazil - Doctorate
Effective date (Start): April 01, 2016
Effective date (End): May 11, 2019
Field of knowledge:Agronomical Sciences - Agronomy
Principal Investigator:Lilian Amorim
Grantee:Isabela Vescove Primiano
Home Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
Associated research grant:13/24003-9 - Grape diseases: epidemiology, damage assessment and control, AP.TEM
Associated scholarship(s):16/25111-8 - Microscopic analysis of different Phakopsora species on Arabidopsis thaliana: a model to investigate fungal colonization, BE.EP.DR

Abstract

Plant diseases caused by biotrophic pathogens, as rusts, are a compatible interaction between a pathogen and its host cells. These parasitic pathogens cause minimum damage to the host and do not cause cell death. On the other hand, hemibiotrophic and necrotrophic pathogens have more aggressive mechanisms of infection and colonization, which usually envolve host tissue death. Grapevine rust (Phakopsora euvitis) and soybean rust (P. pachyrhizi), both of the genus Phakopsora, do not have the same standard behavior as other rusts, like Puccinia and Uromyces. It is usual the occurrence of host necrosis and premature defoliation in rusts caused by Phakopsora. Disease cycle of soybean rust is very distinct from other rusts, as the pathogen can infect and overwinter different hosts (vs. high specificity), the infection occurs through direct penetration (vs. penetration through natural openings) and the lesions expand with several pustules (vs. single pustule per lesion). However, the effects and relative importance of each component at disease epidemiology is not clear. Grapevine rust presents symptoms similar to soybean rust, as high frequency of pustules on leaves, necrosis and defoliation. Recent studies at ESALQ showed that P. euvitis colonization in Niagara Rosada reduces accumulation of carbohydrates and root biomass, suggesting that this disease also reduces the vigor of the plant. However, few studies about the cycle of grapevine rust caused by P. euvitis were developed until now. Comparative epidemiology is an usual tool in epidemiological studies, with analytical and synoptic objectives. In comparative epidemiology, diversity of plant disease epidemics is reduced to some critical elements that are able to distinguish or aggregate systems for comparative purposes. Comparison is an important research tool and most of statistical tests were based on it. The project objective is to understand the mechanisms related to the aggressiveness of rusts of the genus Phakopsora. Comparative studies of histopathology and epidemiological components will be carried out in both rusts of the genus Phakopsora (P. euvitis and P. pachyrhizi), and in bean rust, considered as a control treatment (Uromyces appendiculatus). Infection mechanisms, the establishment of infection and the end of colonization will be analyzed at the three rusts using conventional histopathological techniques, such as light and electron microscopy. Monocyclic component of each rust, in controlled conditions, and temporal disease progress in plots, based in symptoms and defoliation, will be analyzed based on comparative epidemiology. We intend to request a Research Scholarship (Bolsa Estágio de Pesquisa no Exterior - BEPE) for complement histopathological comparative study of rusts, using a fluorescence method for microscopic resolution without pathogen gene mutation, at University of Aachen (Rheinisch-WestfälischeTechnische Hochschule Aachen University), Germany, with Dr. Ulrich Schaffrath. This research group has experience at histopathology area, mainly working with Phakopsora pachyrhizi. (AU)

Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
PRIMIANO, V, I.; LOEHRER, M.; SCHAFFRATH, U.; AMORIM, L. Formation of satellite uredinia as an important trait related to grapevine colonization by Phakopsora meliosmae-myrianthae. PLANT PATHOLOGY, v. 68, n. 9, p. 1732-1740, DEC 2019. Web of Science Citations: 0.
PRIMIANO, I. V.; LOEHRER, M.; AMORIM, L.; SCHAFFRATH, U. Asian grapevine leaf rust caused by Phakopsora euvitis: an important disease in Brazil. PLANT PATHOLOGY, v. 66, n. 5, p. 691-701, JUN 2017. Web of Science Citations: 10.

Please report errors in scientific publications list by writing to: cdi@fapesp.br.