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

Abstract

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.

Relationships between leaf pigments and photosynthesis in common bean plants infected by anthracnose

“…Berova et al (2007) compared four cultivars of Phaseolus vulgaris infected by two bacteria (Xanthomonas campestris and Pseudomonas syringae) and found that chlorophyll a and b were negatively affected. Scarpari et al (2005) reported reductions in chlorophyll a and b in Theobroma cacao plants infected by the pathogen Crinipellis perniciosa. Santos et al (2005) also described the consequences of Phaeoacremonium angustius and Phaeomoniella chlamydospora infection in two Vitis vinifera cultivars.…”

Carbon source-induced changes in the physiology of the cacao pathogen Moniliophthora perniciosa (Basidiomycetes) affect mycelial morphology and secretion of necrosis-inducing proteins

“…During infection, the nutritional offer of the plant to a phytopathogenic fungus may change, e.g., during Moniliophthora perniciosa x Theobroma cacao interaction there is a clear correlation between fungal differentiation and plant responses (Evans and Prior, 1987;Frias et al, 1991), confirmed by biochemical and nutritional alterations that occur during in vivo infection (Orchard et al, 1994;Scarpari et al, 2005;Kilaru and Hasenstein, 2005;Kilaru et al, 2007).…”

“…Interactions in this pathosystem are complex and include sequential alterations or differentiation in the fungus (germination, penetration, colonization, dikaryotization, and fructification; Silva et al, 2002;Kilaru and Hasenstein, 2005) and in the plant (hypertrophy, hyperplasia, branching, activation of defense responses, and cell death; Orchard et al, 1994;Scarpari et al, 2005;Ceita et al, 2007). Recently, in-depth studies of this fungus have been published: M. perniciosa was found to produce hormones and alter endogenous auxin and salicylic acid levels in infected cocoa leaves (Kilaru et al, 2007), as well as necrosis-inducing proteins during infection, i.e., Mp-NeP1 and Mp-NeP2, which are differentially secreted during the course of infection in planta ; Rincones et al (2008) found that genes expressed in the biotrophic phase of M. perniciosa are under catabolite and nitrogen repression.…”

The Trofobiose Theory and organic agriculture: the active mobilization of nutrients and the use of rock powder as a tool for sustainability

“…Recently, Scarpari et al 2005 reported their research fi ndings on a fungi disease caused by Crinipelli perniciosa which is known to cause severe devastation of cocoa. Scarpari et al pointed out some details on hormonal disequilibrium and the extra doses of nutrients as well as some others chemicals defenses (liberation of 10 times more alkaloids -theobromine and caffeine as natural sources of defense against this fungi disease then followed by the degradation of protein and the beginning of apoptosis -the programmatic death of vegetal tissues as a means of isolating the infected tissues.…”