Role of strawberry volatile organic compounds in the development of Botrytis cinerea infection

Abstract

Botrytis cinerea, the main pathogen of strawberry, has the ability to remain quiescent in unripe tissue and develop disease symptoms in ripe fruit. As strawberry ripening is characterized by an increase of aroma compounds, the role of volatile emission in the development of infection was investigated. Thirty-five strawberry volatile organic compounds (VOCs) were tested on B. cinerea in vitro and volatile emission was analysed in strawberry harvested at four ripening stages by headspace solid-phase microextraction/gas chromatography-mass spectrometry and proton transfer reactiontime of flight-mass spectrometry. The coupling of such data sets made it possible to conclude that key strawberry aroma compounds stimulate B. cinerea conidial germination and some typical wound-volatiles stimulate pathogen conidial germination or mycelial growth. This study is the first report of fungal stimulation by some VOCs naturally occurring in strawberry: the esters ethyl butanoate, cis-3-hexenyl acetate, trans-2-hexenyl acetate, methyl butanoate and hexyl butanoate, the furanones furaneol and mesifurane, and the alcohol trans-2-hexenol. The results of this work provide advances in understanding the functional role of fruit VOCs and suggest, for the first time, that fruit VOCs may influence the development of B. cinerea from the latent phase and that they could favour the invasive growth of B. cinerea after wounding. In particular, ethyl butanoate and furaneol could signal strawberry ripening, and the green leaf volatiles trans-2-hexenol, trans-2-hexenyl acetate and cis-3-hexenyl acetate could signal the presence of damaged tissues that are easier sites for penetration by B. cinerea.

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

“…In strawberry, these volatile showed a stimulatory effect on conidial germination of Botrytis cinerea (Neri et al, 2015). In the present study, a marked increase of 6-methyl-5-hepten-1-one was observed in inoculated fruit, even during the first few hours after inoculation, and it was progressive over time particularly at 20 °C, following a similar pattern of the Alternaria rot development.…”

“…Fungi, plants, and fruits produce a variety of volatile metabolites that could act as signals of plant disease (Jansen et al, 2011), or as signaling molecules that play a vital role in the activation of disease resistance mechanisms. Also, could act as antimicrobial agent (Neri et al, 2015), or could serve as markers for the detection of the spoilage pathogens (Vikram et al, 2004;Moalemiyan et al, 2006). In this study, were identified some VMs released from strains of A. alternata growing on PDA plates.…”

“…Also, volatile metabolites (VM) released during the infection can alter the fruit flavor. Some volatiles act as signals of plant diseases (Jansen et al, 2011), or as an antimicrobial agent (Neri et al, 2015), keeping the inactive state of fungi, and contribute to plant resistance against pathogens (QuintanaRodriguez et al, 2015).…”

New non-chemical postharvest technologies reducing berry contamination

“…Nigro et al (2000) found that UV-C 254 nm reduces postharvest decay on strawberries. Neri et al (2014) ran a test on thirty-five strawberry volatile organic compounds on B. cinerea in vitro and found that 14 compounds significantly influenced the conidial germination of B. cinerea. Tezotto-Uliana et al (2014) ran a test on pre and post-harvest chitosan coating in order to prolong the shelf life of raspberries.…”

Use of Nonanal-wax as Postharvest Fungicide of Tomato against <i>Botrytis cinerea</i>

“…For some VOCs, the exposure to the higher concentration used in the experiments (12.3 μL L -1 ) reduced the development of Botrytis cinerea. In particular, the aldehydes trans-2-hexenal and nonanal completely inhibited conidial germination and nonanal showed the best reduction of mycelial growth (-66.8%) at this concentration [13]. Nowadays, application of plant volatiles as inhibitory compounds towards fungal pathogens could be another interesting alternative.…”