"Can abiotic stresses alter plant-pathogen relationships in the Thekopsora americana - Rubus idaeus pathosystem? Epidemiological, physiological and histopathological analyses"

• Grant number: 22/00888-0
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: June 01, 2022
• End date: June 29, 2025
• Field of knowledge: Biological Sciences - Botany - Applied Botany
• Principal Investigator: Beatriz Appezzato da Glória
• Grantee: Lucas Henrique Santos Barbosa
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Associated research grant: 19/13191-5 - Epidemiological components, damage characterization and control of tropical and temperate rusts at a global climate change scenario, AP.TEM
• Associated scholarship(s): 24/02834-0 - Subcellular changes caused by late leaf rust in raspberries and the effect of water deficit on disease severity: confocal and transmission electron microscopy analyses, BE.EP.DR

Abstract

Global climate change has great potential to impact agricultural production, whether by directly interfering with the plant or its relationship with diseases. Some plant diseases caused by basidiomycete fungi known as rusts have shown relevance in places where they were not important, causing negative impacts to the economy, the environment and society. In the United States, for example, higher temperatures have favored the survival of rust spores in soybean (Glycine max L.) during the winter and the beginning of a new cycle of infection in the following crop. Studies conducted by our team on vine rust (Vitis labrusca L.) 'Niagara Rosada' demonstrated that, although the temperature of 30 °C is not ideal for the development of the pathogen, the pathogen/high temperature combination resulted in more severe leaf damage. In addition to heat stress, our team has been conducting experiments to verify the plant-pathogen interaction and water deficit. Late leaf rust (Thekopsora americana) of red raspberry (Rubus idaeus L.), the main crop disease in Brazil that can lead to production losses of up to 30%, was studied. The pathogen causes lesions on fruits, depreciating them for the fresh fruit market, as well as lesions on leaves that can lead to early defoliation of the plant directly interfering with its productivity. In the first studies carried out on water deficit, the inoculation of the T. americana fungus was carried out after water limitation, which resulted in a lower incidence and severity of the disease, probably due to stomatal closure, which is the natural route of entry of the pathogen into the leaf. However, if the inoculation of the fungus T. americana had been carried out prior to the water limitation, the plant responses would probably have been different, justifying further analysis. Since the cultivation of red raspberry has been increasing in small rural properties in the south and southeast, mainly in the state of São Paulo, where higher temperatures and longer periods of drought may occur, studies on the subject are necessary. Therefore, the present project proposes to evaluate the effect of temperature elevation and water limitation on the relationships between plants of Rubus idaeus cv. Heritage and the fungus Thekopsora americana through epidemiological, histopathological and physiological analyses.