Accumulation of soluble phenolic compounds in sunflower capitula correlates with resistance to Sclerotinia sclerotiorum

• Published in: Euphytica 2003-01, Vol.132 (3), p.321-329
• Main Authors: PRATS, E, BAZZALO, M. E, LEON, A, JORRIN, J. V
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; Genetics and breeding of economic plants; Genotypes; Immunization; Pathology, epidemiology, host-fungus relationships. Damages, economic importance; Pest resistance; Phenols; Phytopathology. Animal pests. Plant and forest protection; Plant pathogens; Varietal selection. Specialized plant breeding, plant breeding aims
• ISSN: 0014-2336; 1573-5060
• DOI: 10.1023/A:1025046723320

Disease symptoms and total soluble phenolics content have been analysed in four sunflower (Helianthus annuus L.)lines with different resistance levels(from highly susceptible to resistant) to head rot caused by Sclerotinia sclerotiorum (Lib.) de Bary. At the beginning of the flowering stage, capitula were inoculated by spraying with a water suspension of ascospores, and disease symptoms were evaluated from day 6 to day14 after inoculation. The most susceptible genotypes showed all their ovaries to be necrosed and abundant lesions in corollas, bracts and receptacle. In the resistant line, the ovary and corolla were only partially necrosed with no symptoms in the bracts or the receptacle. Total soluble phenolics were extracted and quantified from different parts of the capitulum in both inoculated and non-inoculated plants. The amount of phenolic compounds depended on the sunflower line, the time after inoculation, and the tissue. Higher constitutive and induced phenolic content as well as phenylalanine ammonia-lyase activity were present in the most resistant line, these differences correlated with the absence/presence of disease symptoms.[PUBLICATION ABSTRACT]