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Poster: Diseases of Plants: New & Emerging Diseases


Unraveling Silverleaf disease: Reversion of foliar symptoms and plants recovery
D. GRINBERGS (1), A. France (1), J. Chilian (1) (1) Instituto de Investigaciones Agropecuarias, Chile

Silverleaf, caused by the Basidiomycete Chondrostereum purpureum, is an important disease in fruit trees which produce wood necrosis and leaves silvering. In apple has been increasing due to changes in management, reducing orchards viability. Plants deteriorate their physiological condition, being water uptake and chlorophyll content the most affected parameters. The latter alters photosynthesis, reducing fruit yield and quality. Field studies have shown the spontaneous reversion of foliar symptoms, thus, the objective was to compare the physiological and sanitary condition of Brookfield plants before and after reversion. The sanitary condition was determined assessing symptoms severity, isolating the fungus on PDA, amplificating the large intergenic spacer (IGS) rDNA regiĆ³n and measuring foliar endopoligalacturonase concentration using DAS-ELISA. Physiological condition was measured through xylem water potential, chlorophyll fluorescence, a, b and a + b chlorophyll content and stomatal conductance. Besides, yield and fruit quality parameters such as color and starch were assessed. Isolation, PCR and ELISA indicated that the fungus was present in symptomatic plants and after reversion. Symptomatic plants presented alterations in all physiological parameters (P<0,05%), reduction of yield (38%), maduration disorders and lack of color. However, after reversion of silvering, physiological condition, yield and fruit quality were restored.