Effect of abiotic stresses on the progress of rust (Neophysopella tropicalis) in grapevine

Author(s)

Lucas Santos Sales

• Document type: Master's Dissertation
• Press: Piracicaba.
• Institution: Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC)
• Defense date: 2025-01-21

Examining board members

Lilian Amorim; Ivan Herman Fischer; Rafael Vasconcelos Ribeiro

• Advisor: Lilian Amorim

Abstract

The occurrence of rust has increased considerably in recent years in various agricultural regions around the world, resulting in various economic and environmental damages. Only recently, research on the effect of the combination of biotic and abiotic stresses, in simultaneous occurrence, on the physiology of cultivated plants are being carried out. Although the individual effects of water and heat stress on the occurrence of Asian grapevine rust (Neophysopella tropicalis) are well characterized, their combined effect has not yet been studied. This study aimed to evaluate the progress and effects of rust in grapevines under different abiotic stresses. To achieve the proposed objectives, Niagara Rosada grapevine plants were exposed to abiotic stresses (high temperature and/or water deficit) and biotic stress (N. tropicalis) simultaneously. The infectious process and colonization of N. tropicalis in grapevines exposed to different combinations of abiotic and biotic stresses were evaluated using confocal microscopy techniques. The latent period, lesion density, sporulating area, total lesion area, and urediniospore production per lesion were also assessed. The CO2 assimilation, stomatal conductance, intercellular CO2 concentration, transpiration rate, and quantum efficiency of photosystem II were evaluated in 2 cm2 areas of inoculated leaves. The vegetative development of the grapevines was evaluated by the end of the experiments by weighing the aerial and root fractions and measuring the leaf area. Simultaneous abiotic stresses had little influence on N. tropicalis penetration, latent period, lesion density, and sporulating area. However, exposure to elevated temperatures favored pathogen colonization and reproduction. The combination of abiotic and biotic stresses also significantly reduced net CO2 assimilation due to stomatal limitations and damage to the photosynthetic apparatus. The foliar senescence process in grapevines was accelerated, resulting in a high proportion of chlorosis and necrosis on the leaf blade, in addition to intense defoliation. Together with abiotic stresses, N. tropicalis can cause severe damage to grapevine development, increasing cultivation costs in the current regions where it is found. (AU)

• FAPESP's process: 23/02885-1 - Effect of abiotic stresses on the progress of rust (Neophysopella tropicalis) in grapevine
• Grantee: Lucas Santos Sales
• Support Opportunities: Scholarships in Brazil - Master