Effect of quercetin and umbelliferone on the transcript level of Penicillium expansum genes involved in patulin biosynthesis

Penicillium expansum is commonly associated with patulin accumulation in pome fruits. In in vitro studies, two phenolic compounds (quercetin and umbelliferone) proved to be effective in reducing patulin accumulation, particularly when applied in combination, without consistently affecting mycelial growth. To investigate the mode of action of quercetin and umbelliferone, the expression of five genes likely involved in patulin biosynthesis was evaluated using real-time PCR in the presence and absence of the tested phenolic compounds. The relative expression of genes coding isoepoxydon dehydrogenase (IDH), 6-methylsalicylic acid synthase (msas) and an ATP-binding cassette transporter (peab1) proved to be down-regulated when quercetin and umbelliferone were added in combination. Furthermore, the relative expression of two putative cytochrome P450 monooxygenases (p450-1 and p450-2) was reduced by all treatments, although the combination of the two substances was the most effective. These results provide evidence that quercetin and umbelliferone reduce patulin accumulation by acting on the transcription level of the tested genes

Influence of hot water treatment on brown rot of peach and rapidfruit response to heat stress

Recent results on hot water as an alternative treatment open a new perspective in disease incidencereduction. In the present work peach fruit were wounded, inoculated with conidia of Monilinia laxa and15 min, 3, 6, 12, 24 and 48 h after inoculation treated by dipping in hot water (HT) at 60\u25e6C for 20 s. Theeffect of heat treatment on some cell wall genes involved in ripening such as -galactosidase (-GAL),pectin lyase (PL), polygalacturonase (PG) and pectin methyl esterase (PME), was analyzed by qRT-PCR.The expression levels of defense related genes, phenylalanine ammonia lyase (PAL) and chitinase (CHI),heat stress-related genes such as heat shock proteins 70 and 90 (HSP70, HSP90), and reactive oxygenspecies (ROS) scavenging genes were also evaluated by qRT-PCR. A 100% disease incidence reduction, ascompared to untreated fruit, was obtained by treating 6 and 12 h after inoculation. Moreover, brown rotwas inhibited by 85.7% when fruit were heat-treated 48 h after inoculation. The expression levels of cellwall genes (-GAL, PL, PG and PME) showed a general decrease in HT fruit as compared to the control,whereas PAL, CHI, HSP70 and ROS-scavenging genes increased their expression level in HT samples withrespect to the untreated ones. Our results show a curative activity of heat on peach inoculated withM. laxa 48 h before treatment. Each analyzed gene proved to be differentially expressed following heattreatment

Understanding patulin role in blue mould of apples as a tool to improve its biological control

Patulin ecological role has never been elucidated. Gene disruption was used to alter the sequence of 6-methyl-salicylic acid synthase. Disrupted mutants were significantly less pathogenic and virulent on apples. Mutants were more susceptible to the antioxidant quercetin than the wild type. Patulin seems to have a role in blue mould pathogenic development on apples

Alternaria species causing pomegranate and citrus fruit rots in Albania

The fungal genus Alternaria is a relevant pathogen for several commodities including citrus and pomegranate fruits. On citrus, it mainly causes brown spots on fruits and leaves, whereas on pomegranate, it mostly causes a fruit heart rot. In the present study the presence of Alternaria rots on citrus and pomegranate fruits cultivated in Albania was assessed. Representative fruits were collected from different regions. Nineteen and thirteen Alternaria spp. isolates were obtained from pomegranate and citrus samples, respectively. The isolates were identified at species and morphotype level. Micro and macroscopic features separated isolates into four morphotypes. BLAST and phylogenetic analysis using the SCAR Marker OPA1-3 confirmed the isolate identity. All 32 isolates proved to be Alternaria alternata and belonged mainly to morphotype alternata, followed by limoniasperae and tenuissima. All Alternaria strains proved to possess the pksI gene of alternariol biosynthesis. Citrus isolates were tested for the presence of genes of the biosynthesis of the phytotoxins ACT and ACR, but none of them proved to possess them. Concluding, Alternaria spp. might represent a treat to pomegranate and citrus production in Albania, and thus effective control means are needed

Heat treatment to control brown rot and preserve the fruit quality of peaches

In order to evaluate the efficacy of a hot water (HW) treatment against postharvest diseases of peaches, four varieties ‘Springebelle’, ‘Rich Lady’, ‘Symphonie’ and ‘Benedicte® Meydicte*’ were dipped for 20 sec in water at 60°C. After treatment fruits were stored at 0°C for 4 days, followed by other 4 days of shelf life. Fruit dipped in water at room temperature represented positive control (PC) and fruits no dipped in water were negative control (NC). The HW treatment reduced significantly brown rot in naturally infected peaches with a decay reduction of around 80%. The HW treatment significantly affected also the epiphytic microflora population, in fact on HW treated fruits the fungal population was reduced by 70%, the yeast population by 20% and the bacteria population was completely inhibited with respect PC treated fruits. In addition the physico-chemical analysis showed no substantially differences between HW, PC and NC treated fruits, but only a slight improvement in acceptability for HW treated fruits. Since our results, HW treatment may have commercial application in the control of brown rot, reducing the pathogen inoculum and microflora population on fruit surface, keeping quality and prolonging shelf life in several varieties of peaches. HW treatment seems a potential postharvest successful mean to reduce brown rot in peach, maintaining fruit quality