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

David Encinas-Basurto1, María Isabel Valenzuela-Quintanar2, Alberto Sánchez-Estrada1, Martín Ernesto Tiznado-Hernández1, Armida Rodríguez-Félix1, and Rosalba Troncoso-Rojas1*
 
Alternaria alternata (Fr.) Keissl. 1912is one of the main fungal pathogens that infect tomato (Solanum lycopersicum L.) during cold storage affecting postharvest quality and marketing. During fungal infections, fruits and fungi release specific volatile metabolites (VM) that could alter the fruit aroma, or could mediate resistance response in the fruit, or they also could suggest the possible status of fungal attack. The detection of the VM released during the tomato-Alternaria interaction could contribute to the development of ecofriendly and harmless strategies for its control. In this study, the profile of VM of fresh tomatoes inoculated with A. alternata, were analyzed by solid phase microextraction and gas chromatography-mass spectrometry (SPME-GC-MS) during storage at 15 and 20 °C for 48 h, respectively. Changes in the profile of VM were observed between control and inoculated fruit since the first few hour post-inoculation. Some VM (3-methyl-2-butenal, dimethyl disulfide, 1-butenol, hexanol, 2-methyl-1-butanol acetate, among others) were only detected in inoculated fruit, so they appear to be synthesized by the presence of the pathogen. Also, a marked increase of 3-methyl-1-butanol and 6-methyl-5-hepten-1-one were observed in inoculated fruit, and they were progressive over time particularly at 20 °C. In conclusion, A. alternata induced changes in the profile of volatile metabolites released by tomato fruit. Some of the VM released during tomato-A. alternata interaction, were synthesized or stimulated by the fungal attack. These results contribute to the current knowledge about the profile of VM released during the fruit-pathogen interaction.
Keywords: Volatile metabolites, fresh tomatoes, Alternaria alternata, cold storage temperatures, SPME-GC-MS
1Centro de Investigación en Alimentación y Desarrollo, A.C. (CIAD), Coordinación de Tecnología de Alimentos de Origen Vegetal, Carretera a la Victoria km 0.6, CP 83304, Hermosillo, Sonora, México. *Corresponding author (rtroncoso@ciad.mx).
2Centro de Investigación en Alimentación y Desarrollo, A.C. (CIAD), Coordinación de Ciencia de los Alimentos, Carretera a la Victoria km 0.6, CP 83304, Hermosillo, Sonora, México.