Phakopsora euvitis Causes Unusual Damage to Leaves and Modifies Carbohydrate Metabolism in Grapevine

Autor(es)

Nogueira Junior, Antonio F. ^[1] ; Ribeiro, Rafael V. ^[2] ; Appezzato-da-Gloria, Beatriz ^[1] ; Soares, Marli K. M. ^[1] ; Rasera, Julia B. ^[1] ; Amorim, Lilian ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Dept Epidemiol, Plant Pathol, ESALQ, Piracicaba - Brazil

^[2] Univ Estadual Campinas, Inst Biol, Dept Plant Biol, Campinas, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: FRONTIERS IN PLANT SCIENCE; v. 8, SEP 26 2017.
• Citações Web of Science: 8

Resumo

Asian grapevine rust (Phakopsora euvitis) is a serious disease, which causes severe leaf necrosis and early plant defoliation. These symptoms are unusual for a strict biotrophic pathogen. This work was performed to quantify the effects of P. euvitis on photosynthesis, carbohydrates, and biomass accumulation of grapevine. The reduction in photosynthetic efficiency of the green leaf tissue surrounding the lesions was quantified using the virtual lesion concept (beta parameter). Gas exchange and responses of CO2 assimilation to increasing intercellular CO2 concentration were analyzed. Histopathological analyses and quantification of starch were also performed on diseased leaves. Biomass and carbohydrate accumulation were quantified in different organs of diseased and healthy plants. Rust reduced the photosynthetic rate, and beta was estimated at 5.78, indicating a large virtual lesion. Mesophyll conductance, maximum rubisco carboxylation rate, and regeneration of ribulose-1,5-bisphosphate dependent on electron transport rate were reduced, causing diffusive and biochemical limitations to photosynthesis. Hypertrophy, chloroplast degeneration of mesophyll cells, and starch accumulation in cells close to lesions were observed. Root carbohydrate concentration was reduced, even at low rust severity. Asian grapevine rust dramatically reduced photosynthesis and altered the dynamics of production and accumulation of carbohydrates, unlike strict biotrophic pathogens. The reduction in carbohydrate reserves in roots would support polyetic damage on grapevine, caused by a polycyclic disease. (AU)

• Processo FAPESP: 13/24003-9 - Epidemiologia, avaliação de danos e controle de doenças da videira
• Beneficiário: Lilian Amorim
• Modalidade de apoio: Auxílio à Pesquisa - Temático