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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Virtual lesions and photosynthetic damage caused by Plasmopara viticola in Vitis labrusca

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Author(s):
Nogueira Junior, Antonio F. [1] ; Ribeiro, Rafael V. [2] ; Marcos, Fernanda C. C. [2] ; Amorim, Lilian [1]
Total Authors: 4
Affiliation:
[1] Univ Sao Paulo, Dept Plant Pathol & Nematol, Coll Agr Luiz de Queiroz ESALQ, BR-13418900 Piracicaba, SP - Brazil
[2] Univ Campinas UNICAMP, Dept Plant Biol, Inst Biol, BR-13083970 Campinas, SP - Brazil
Total Affiliations: 2
Document type: Journal article
Source: European Journal of Plant Pathology; v. 155, n. 2, p. 545-555, OCT 2019.
Web of Science Citations: 0
Abstract

Downy mildew caused by Plasmopara viticola is the most destructive disease of grapevines. However, the mechanisms of damage caused by P. viticola to photosynthesis in Vitis labrusca remain unknown. Our aim was to quantify the effects of downy mildew on leaf gas exchange in V. labrusca, estimating virtual lesions (regions surrounding lesions where photosynthesis is null) and evaluating limitations imposed on photosynthesis. Grapevine plants cv. Niagara Rosada were inoculated with varying sporangia concentrations of P. viticola to obtain a range of disease severities. Leaf gas exchange and photochemical activity were measured in both diseased and healthy leaves and the eq. Y = (1 - x)(beta) was used to correlate photosynthetic variables (Y) and disease severity (x), with beta representing the ratio between virtual and visual lesions. Our results revealed a beta-value of 2.79, indicating moderate virtual lesions. Photosynthetic rates decreased by about 83% in leaves with 50% of downy mildew severity and there were significant impairments in the maximum Rubisco carboxylation rate, maximum rate of electron transport driving regeneration of ribulose-1,5-bisphosphate, effective quantum efficiency of photosystem II and mesophyll conductance, even in plants showing less than 10% of downy mildew severity. In conclusion, our results not only reveal how P. viticola affects photosynthesis in V. labrusca, but also give insights into how crop modelling would be improved by taking into account virtual lesions and photosynthetic damage. Such key information is needed for simulation models that quantitatively integrate the interaction between disease and crop growth. (AU)

FAPESP's process: 17/02432-6 - Simulation modeling of damage caused by downy mildew and grapevine rust in Vitis spp. under different training systems
Grantee:Antonio Fernandes Nogueira Júnior
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 13/24003-9 - Grape diseases: epidemiology, damage assessment and control
Grantee:Lilian Amorim
Support type: Research Projects - Thematic Grants