Effects of 1-MCP and dynamic controlled atmosphere on apple fruit rot caused by Fusarium avenaceum

Abstract

Fusarium species are increasingly detected as the causal agents of decay of stored apple fruits. Fusarium avenaceum is particularly significant due to its predominant occurrence among Fusarium species in stored apple fruits and its ability to produce mycotoxins. Treatments with 1-methylcyclopropene (1-MCP) and different storage conditions affect the aggressiveness of F. avenaceum and development of fungal-caused decay in stored apple fruits. In this study, apple fruits (cv. 'Granny Smith') were treated with 1-MCP, and artificially inoculated with F. avenaceum. The isolate used for inoculation, originating from apple fruit, was identified based on morphological characteristics and by polymerase chain reaction (PCR) using a species-specific primer pair (FA-ITSF and FA-ITSR) for F. avenaceum. After inoculation, treated and untreated fruits were stored at room temperature and cold-stored under dynamic controlled atmosphere (DCA). Diameters of necrotic lesions were measured after 7, 14 and 21 days of incubation on fruits stored at room temperature, while necrosis diameters on DCA-stored fruits were measured immediately at the end of storage period (143 days), and after 7, 14 and 21 days of additional incubation at room temperature. The results show that treatment with 1-MCP inhibits the development of F. avenaceum on apple fruits during storage under DCA. However, after storage, i.e. during incubation at room temperature, no significant difference between 1-MCP-treated and untreated fruits was observed. On fruits stored at room temperature only, no difference between 1-MCP-treated and untreated fruits was observed. However, 1-MCP-treated fruits stored at room temperature only developed significantly smaller necrosis lesions compared to 1-MCP-treated and DCA stored fruits. It infers that both 1-MCP treatment and DCA storage inhibit fungal decay caused by F. avenaceum on apple fruits. However, the effects do not persist after storage.

Vrste roda Fusarium sve češće se javljaju kao prouzrokovači truleži plodova jabuke u skladištima. Vrsta Fusarium avenaceum je od posebnog značaja zbog dominacije u odnosu na ostale Fusarium vrste na uskladištenim plodovima, kao i sposobnosti da proizvodi mikotoksine. Upotreba 1-metilciklopropena (1-MCP) i različiti uslovi skladištenja utiču na agresivnost F. avenaceum i pojavu truleži plodova prouzrokovane gljivama. U ovom radu, plodovi jabuke sorte 'Granny Smith' tretirani su sa 1-MCP i veštački inokulisani izolatom vrste F. avenaceum. Izolat F. avenaceum korišćen za inokulaciju je poreklom iz ploda jabuke i identifikovan je na osnovu morfoloških karakteristika i lančanom reakcijom polimeraze (PCR) upotrebom para prajmera specifičnog za vrstu F. avenaceum (FA-ITSF i FA-ITSR). Nakon inokulacije, tretirani i netretirani plodovi su čuvani na sobnoj temperaturi i u hladnjači sa dinamički kontrolisanom atmosferom (DCA). Ocena razvoja nekroze na plodovima čuvanim na sobnoj temperaturi vršena je nakon 7, 14 i 21 dan inkubacije, a na plodovima čuvanim u DCA hladnjači odmah nakon skladištenja (143 dana), te nakon 7, 14 i 21 dan dodatne inkubacije na sobnoj temperaturi. Ostvareni rezultati pokazuju da tretman sa 1-MCP inhibira razvoj F. avenaceum na plodovima jabuke tokom čuvanja u DCA hladnjači. Međutim, po iznošenju jabuka iz skladišta i inkubaciji na sobnoj temperaturi, efekat 1-MCP prestaje i razlike u razvoju nekroze na tretiranim i netretiranim plodovima nisu značajne. Na plodovima koji su čuvani samo u uslovima sobne temperature nisu registrovane razlike u razvoju nekroze između netretiranih i plodova koji su tretirani sa 1-MCP. Tokom inkubacije na sobnoj temperaturi, na tretiranim plodovima koji su čuvani samo u uslovima sobne temperature, razvoj nekroze je značajno manji u odnosu na tretirane plodove prethodno skladištene u DCA hladnjači. Može se zaključiti da tretiranje sa 1-MCP i DCA uslovi skladištenja inhibiraju pojavu truleži plodova jabuke prouzrokovanu vrstom F. avenaceum tokom skladištenja, ali se efekti ne zadržavaju nakon iskladištenja.