Fungal pathogens, such as Penicillium expansum and Botrytis cinerea, can cause severe post-harvest losses of apple fruits. On stored fruits, the control of these diseases is mainly dependent on refrigeration, controlled atmosphere and fungicides. However, in the last few years, new defence strategies based on the induction of resistance have been investigated. The objective of our study was to determine the effectiveness of treatment by chemical and biological inducers of resistance in the apple fruit (Malus domestica L. cv Golden delicious)–P. expansum interaction. Benzothiadiazole (BTH), β-aminobutirric acid and Methyl Jasmonate were used as the chemical inducers, while two strains of Pseudomonas syringae (1,3S and 48SR2) and five isolates of Trichoderma (T. atroviride P1, T. harzianum T22, T. harzianum T67, T. resei T34 and Trichoderma spp. 8009) were tested as biological inducers. Our analyses, carried out according to the method of Porat et al. (2003), showed that chemical and biological products did not control the infection when applied with the aim of inducing resistance, while they exerted a direct antimicrobial activity against P. expansum. The antifungal activity of chemical inducers was also confirmed by in-vitro tests. By reverse trascription-PCR analyses, increases in mRNA levels of some pathogenesis-related proteins (PR1, PR2, PR5 and PR8) were evident in apple fruits treated with BTH and P. syringae 1,3S. These results indicate that the treatments can trigger resistance responses in apple fruits, although these responses are ineffective for limiting the infections. Thorough examinations directed at evaluating the presence of investigated PR proteins will be necessary to clarify the lack in the protective effects of the induced resistance. However, it must be consideredd that the chemicals defined as resistance inducers showed direct activities against P. expasnum. Therefore, in these kinds of surveys, the antimicrobial activity of chemical inducers of resistance should always be preliminarily verified
Postharvest control of disease on apple fruits: induced resistance trials
QUAGLIA, Mara;FABRIZI, MARIO;EDERLI, Luisa;PASQUALINI, Stefania;ZAZZERINI, Antonio
2009
Abstract
Fungal pathogens, such as Penicillium expansum and Botrytis cinerea, can cause severe post-harvest losses of apple fruits. On stored fruits, the control of these diseases is mainly dependent on refrigeration, controlled atmosphere and fungicides. However, in the last few years, new defence strategies based on the induction of resistance have been investigated. The objective of our study was to determine the effectiveness of treatment by chemical and biological inducers of resistance in the apple fruit (Malus domestica L. cv Golden delicious)–P. expansum interaction. Benzothiadiazole (BTH), β-aminobutirric acid and Methyl Jasmonate were used as the chemical inducers, while two strains of Pseudomonas syringae (1,3S and 48SR2) and five isolates of Trichoderma (T. atroviride P1, T. harzianum T22, T. harzianum T67, T. resei T34 and Trichoderma spp. 8009) were tested as biological inducers. Our analyses, carried out according to the method of Porat et al. (2003), showed that chemical and biological products did not control the infection when applied with the aim of inducing resistance, while they exerted a direct antimicrobial activity against P. expansum. The antifungal activity of chemical inducers was also confirmed by in-vitro tests. By reverse trascription-PCR analyses, increases in mRNA levels of some pathogenesis-related proteins (PR1, PR2, PR5 and PR8) were evident in apple fruits treated with BTH and P. syringae 1,3S. These results indicate that the treatments can trigger resistance responses in apple fruits, although these responses are ineffective for limiting the infections. Thorough examinations directed at evaluating the presence of investigated PR proteins will be necessary to clarify the lack in the protective effects of the induced resistance. However, it must be consideredd that the chemicals defined as resistance inducers showed direct activities against P. expasnum. Therefore, in these kinds of surveys, the antimicrobial activity of chemical inducers of resistance should always be preliminarily verifiedI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
