Induction of chalcone synthase and phenylalanine ammonia-lyase by salicylic acid and Colletotrichum lindemuthianum in common bean

Abstract

The activities of the enzymes chalcone synthase (CHS) and phenylalanine ammonia-lyase (PAL) were measured in leaf extracts obtained from four cultivars of the common bean (AB 136, Rio Tibagi, Carioca and Macanudo). Two stages of plant development were examined: plantlets (V2) and the onset of blooming (R6). Initially, the plants were either treated with salicylic acid or inoculated with the delta race of Colletotrichum lindemuthianum (inductive fungus) and after three days they were evaluated for enzyme activity. Afterwards, all plants were inoculated (challenged) with the virulent pathotype 33/95 of C. lindemuthianum except for the water control. Five days later, the activities of PAL and CHS were evaluated. There were significant changes in the activities of both enzymes three days after treatment with salicylic acid or inductive fungus when compared to the control. Five days after inoculation with with the virulent pathotype 33/95 of C. lindemuthianum CHS activity in the Macanudo was similar to control plants that were not treated with salicylic acid or the inductive fungus but inoculated with 33/95 C. lindemuthianum. The increase in enzyme activity after challenge with 33/95 C. lindemuthianum was greatest for the salicylic acid treatment in the cultivar AB 136, followed by Rio Tibagi and Carioca.

Heat shock and salicylic acid on postharvest preservation of organic strawberries

“…This increased activity causes the accumulation of phenolic compounds (Lopez-Galvez et al, 1996;Peiser et al, 1998), which seems to be related to defense mechanisms of the fruit via oxidative metabolism enzymes such as peroxidases (PO) and polyphenoloxidases (PPO). These enzymes lead to oxidative degradation of phenolic compounds, close to the site of cell decompartmentalization caused by pathogens (Campos et al 2003). The damage caused by pathogens to cells also contribute to the increased levels of pre-existing phenolic compounds released from vacuoles, oxidized to quinones (Thipyapong et al, 2004), which exhibit antimicrobial activity (Jung et al, 2004) .…”

“…However, at 14 days, heat shock-treated strawberries had lower content than the other treatments. Exogenous application of salicylic acid can activate the metabolic pathway for the synthesis of phenylpropanoids (flavonoid compounds) involved in mechanisms of resistance to plant pathogens (Campos et al, 2003). The defense responses induced by salicylic acid are probably involved in the expression of a number of defense genes, especially those encoding pathogenesis related proteins such as chitinase, â-1,3-glucanase and peroxidase (Qin et al, 2003).…”

Genotypic differences in cyanogenic glycosides levels of compatible Prunus persica P. persica and incompatible P. persica P. mume combinations

“…The phenylalanine ammonia-lyase (PAL) activity was determined according to the methods described by Hyodo et al (1978) and modified by Campos et al (2003). For the extraction, 500 mg of fresh bark tissue was collected, macerated using a micro-triturator (at ± 4 °C) with 4 mL of 50 mm sodium borate buffer (pH 8.5) containing 25 g·L -1 of polyvinylpyrrolidone and 4 mL·L -1 of mercaptoethanol.…”

Essential oil of Cymbopogon flexuosus, Vernonia polyanthes and potassium phosphite in control of bean anthracnose

“…flaccumfaciens in common bean by 76%, and increased dry weight of shoots and roots of treated plants. Campos et al (2003) reported that bean plants Pérola cultivar treated with salicylic acid had higher PAL activity than plants treated with water, and plants challenged with the pathogen C. lindemuthiahum showed higher PAL activity than non-inoculated plants.…”