Biochemical changes during the development of witches' broom: the most important disease of cocoa in Brazil caused by Crinipellis perniciosa

• Published in: Journal of experimental botany Vol. 56; no. 413; pp. 865 - 877
• Main Authors: Scarpari, L. M, Meinhardt, L. W, Mazzafera, P, Pomella, A. W. V, Schiavinato, M. A, Cascardo, J. C. M, Pereira, G. A. G
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.03.2005; Oxford Publishing Limited (England)
• Subjects: Agaricales - physiology; alkaloids; Amino acids; Amino Acids - metabolism; Asparagine; basidiomycete; Basidiomycetes; Biological and medical sciences; biotrophic; Brazil; Brooms; Cacao; Cacao - metabolism; Cacao - microbiology; Carbohydrate Metabolism; chemical constituents of plants; Cocoa; cocoa products; Crinipellis perniciosa; disease course; ethylene; Ethylenes - metabolism; Fatty acids; Fatty Acids - metabolism; Flavonoids - metabolism; Fundamental and applied biological sciences. Psychology; fungal diseases of plants; Fungi; Glycerol - metabolism; Infections; Inoculation; Malondialdehyde - metabolism; Moniliophthora perniciosa; oxidative stress; Phenols - metabolism; Pigments, Biological - metabolism; Plant diseases; Plant Diseases - microbiology; Plant growth. Development of the storage organs; Plant Leaves - metabolism; plant pathogenic fungi; Plant physiology and development; plant pigments; Plant Stems - metabolism; Plants; RESEARCH PAPER; saprotrophic; soluble solids; specialty crops; tannins; Tannins - metabolism; Theobroma cacao; Vegetative apparatus, growth and morphogenesis. Senescence; witches' broom; Brazil; Oxidative stress; basidiomycete; biotrophic; Ethylene; Basidiomycetes; Fatty acids; Chlorophyll a; Fungi; Alkaloid; Dicotyledones; Sterculiaceae; Aminoacid; Angiospermae; Development; Asparagine; Above ground plant part; Spermatophyta; saprotrophic; Crinipellis perniciosa; tannins; Carotenoid; Theobroma cacao; Thallophyta; Caffeine
• ISSN: 0022-0957; 1460-2431; 1460-2431
• DOI: 10.1093/jxb/eri079

Witches' broom disease (WBD) is caused by the hemibiotrophic basidiomycete fungus Crinipellis perniciosa, which is one of the most important diseases of cocoa in the western hemisphere. In this study, the contents of soluble sugars, amino acids, alkaloids, ethylene, phenolics, tannins, flavonoids, pigments, malondialdehyde (MDA), glycerol, and fatty acids were analysed in cocoa (Theobroma cacao) shoots during the infection and development of WBD. Alterations were observed in the content of soluble sugars (sucrose, glucose, and fructose), asparagine and alkaloids (caffeine and theobromine), ethylene, and tannins. Ethylene and tannins increased prior to symptom development and declined with the death of the infected tissues. Furthermore, MDA and glycerol concentrations were higher in infected tissue than in the controls, while fatty acid composition changed in the infected tissues. Chlorophylls a and b were lower throughout the development of the disease while carotenoids and xanthophylls dropped in the infected tissue by the time of symptom development. These results show co-ordinated biochemical alterations in the infected tissues, indicating major stress responses with the production of ethylene. Ethylene levels are hypothesized to play a key role in broom development. Some of the other biochemical alterations are directly associated with ethylene synthesis and may be important for the modification of its effect on the infected tissues.