Changes in Phenolic Acid Content During Alternaria alternata Infection in Tomato Fruit

Abstract

Phenolic acids are components of the plant defence system; however few studies had been done with fruits. The objective of this experiment was to elucidate the changes in phenolic acid content in tomato fruits in response to pathogenic attack. Tomato fruit ÔPintoÕ was inoculated with spores of Alternaria alternata and stored for 10 days at 25°C and 90-92% of relative humidity. Sampling of epicarp and mesocarp tissues of control and infected tomato fruits were done every 2 days. Phenolic acids were extracted from each tissue and identified by HPLC coupled to a mass spectrometer. Quantification was done based in standard curves. In vitro evaluation of the phenolic acid effect either one-by-one and in a mixture of phenolic acids (MPA) over A. alternata spore germination was done with 25, 50, 100, 200 and 500 mm. It was found caffeic, chlorogenic and vanillic acids in both epicarp and mesocarp tomato tissues before the beginning of the experiment. Infected tomato fruits showed significantly higher concentrations of vanillic acid in the epicarp, only. Chlorogenic acid and the MPA inhibit spore germination by 30%, whereas caffeic acid and vanillic acid inhibit 16% at 500 mm. It was concluded that chlorogenic, vanillic and caffeic acids are phytoanticipins in tomato fruit. The concentration of vanillic acid also increases in tomato fruit epicarp as part of the defence system during a pathogenic attack.www.blackwell-synergy.com

Alterations in volatile metabolites profile of fresh tomatoes in response to Alternaria alternata (Fr.) Keissl. 1912 infection

“…This result coincides with previous experiments carried out in our lab in which tomatoes was infected with the same species of Alternaria (Troncoso-Rojas et al, 2005;Ruelas et al, 2006;Cota et al, 2007). Also, this result agrees with other studies in which tomatoes were inoculated with A. alternata (Reddy et al, 2000).…”

“…At this moment a communication system between plant and pathogen is activated, which triggers the induction of defense mechanisms of the plant. Some of these events considered as part of the defense mechanisms include the production of reactive oxygen species, synthesis of phytoalexins such as phenolic compounds (Ruelas et al, 2006). Besides, modifications in structural defenses (random creation of links between cell wall polymers, lignification) increase the activity of pathogenesisrelated proteins (Cota et al, 2007), among others (Thatcher et al, 2005).…”

“…Keissl. 1912 (Zitter andWien, 1984;Ruelas et al, 2006), which is one of the most common pathogen causing spoiled tomatoes and it is responsible for black mold disease (Troncoso-Rojas and Tiznado-Hernández, 2014). The Alternaria rot symptoms are concentric dark brown spots on the fruit surface with abundant conidia, frequently developed near the peduncle scar or at the blossom-end of the fruit (Snowdon, 2010).…”

Actividad antifúngica de tres extractos de plantas chilenas en Botrytis cinerea

“…All the compounds determined with the HPLC method are reported in literature as antibiotic and fungistatic (Clarke, 1972;San Francisco and Cooper-Driver, 1984;Downum, 1992;Zadernowski et al, 2005;Ruelas et al, 2006;Vermerris and Nicholson, 2006;Feng and Zheng, 2007). For example, a combination of the following acids p-coumaric, ferulic, caffeic, and p-hydroxybenzoic at a concentration of 500 ppm inhibits the mycelial growth of Botrytis cinerea model, where the two first compounds had the more powerful antifungal effect (San Francisco and Cooper-Driver, 1984).…”

“…The following compounds were found in the different samples analyzed: chlorogenic acid, cinnamic acid, p-coumaric acid, ferulic acid, vanillin, vanillic acid, rutin, caffeic acid, 3, 4-hydroxybenzoic acid (veratric acid), 3, 4-dimethoxycinnamic acid (caffeic acid dimethyl ester), and protocatechuic acid. All these compounds have been described as metabolic antimicrobial compounds (Clarke, 1972;Downum, 1992;Zadernowski et al, 2005;Ruelas et al, 2006;Vermerris and Nicholson, 2006;Feng and Zheng, 2007).…”