1,721,050 research outputs found
Scent of a Killer: Microbial Volatilome and Its Role in the Biological Control of Plant Pathogens
No full textThe use of synthetic fungicides represents the most common strategy to control plant pathogens. Excessive and/or long-term distribution of chemicals is responsible for increased levels of environmental pollution, as well as adverse health consequence to humans and animals. These issues are deeply influencing public perception, as reflected by the increasing demand for safer and eco-friendly agricultural commodities and their by-products. A steadily increasing number of research efforts is now devoted to explore the use of safer and innovative approaches to control plant pathogens. The use of microorganisms as biological control agents (BCAs) represents one of the most durable and promising strategies. Among the panoply of microbial mechanisms exerted by BCAs, the production of volatile organic compounds (VOCs) represents an intriguing issue, mostly exploitable in circumstances where a direct contact between the pathogen and its antagonist is not practicable. VOCs are potentially produced by all living microorganisms, and may be active in the biocontrol of phytopathogenic oomycetes, fungi, and bacteria by means of antimicrobial activity and/or other cross-talk interactions. Their biological effects, the reduced residuals in the environment and on agricultural commodities, and the ease of application in different agricultural systems make the use of VOCs a promising and sustainable approach to replace synthetic fungicides in the control of plant pathogens. In this review, we focus on VOCs produced by bacteria and fungi and on their role in the cross-talk existing between the plant pathogens and their host. Biologic systemic effect of the microbial volatile blends on both pathogen and host plant cells is also briefly reviewed
The 2019 international congress on invertebrate pathology and microbial control (SIP-IOBC Joint Meeting)
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DNA biosensors for the detection of aflatoxin producing Aspergillus flavus and A. parasiticus
No full textCharacterisation of isolates of Phoma tracheiphila by RAPD-PCR, microsatellite-primed PCR and rDNA ITS1/ITS2 sequencing and development of specific primers for in planta detection
No full textPluriannual experience in controlling fusarium head blight and the content of DON in infected kernels with de methylation inhibitors (DMI) fungicides.
No full textFusarium head blight (FHB) is the main worldwide wheat disease. In Emilia-Romagna region (Northern Italy), the most frequent species responsible of FHB on durum wheat were Fusarium graminearum and F. culmorum since 1995. FHB can cause losses in production (0.6-2.7 t/Ha) and seed quality, due to kernel infection and micotoxin accumulation. From 2000 to 2006, some DMI commercial fungicides were evaluated for their efficacy in controlling FHB incidence and severity, percentage of infected kernels and deoxynivalenol (DON) content in kernels. DMI were applied at anthesis stage (GS 60-61), in several cultivars of durum wheat, inoculated artificially with a mixture of F. graminearum and F. culmorum toxigenic isolates. Trials, on fourteen cultivars with bromuconazole, prochloraz and tebuconazole were performed from 2000 to 2002 and on four cultivars with epoxiconazole + prochloraz, cyproconazole + prochloraz, metconazole (not yet registered in Italy) from 2005 to 2006. These fungicides significantly reduced incidence and severity of FHB compared with the untreated control. The results showed an average efficacy in reducing the tested parameters of 53% and 68% respectively in the first experiment, 64% and 59% in the second. From 2000 to 2002 on six durum wheat cultivars, bromuconazole, prochloraz and tebuconazole significantly reduced the percentage of F. graminearum and F. culmorum infected kernels by averagely 63% and DON content of 66%, when compared with the untreated control. The knowledge of DMI efficacy in reducing FHB incidence and severity, infected kernels and DON content is very important for setting up disease control strategies
Prothioconazole: a new active substance against fusarium head blight and deoxynivalenol accumulation in wheat kernels.
No full textProthioconazole is a new broad spectrum fungicide belonging to the new chemical class of triazolinthiones. It exhibits ideal systemic properties providing protective, curative and long lasting activity. Prothioconazole has been showed to provide an outstanding control of the major fungal diseases in cereals, mainly those caused by Fusarium species. Fusarium Head Blight (FHB) is a worldwide disease of wheat caused by various fungi including Microdochium nivale and different Fusarium species (mainly F. graminearum and F. culmorum). It has been shown that the most common contaminant associated with FHB infected grains is deoxynivalenol (DON), a trichothecene mycotoxin primarily produced by F. graminearum and F. culmorum. During the 2004-05, 2005-06 and 2006-07 growing seasons, we carried out several field experiments in the North of Italy in order to evaluate the effect of Prothioconazole as a foliar application on FHB development, grain yields and DON accumulation in different cultivars of soft and durum wheat after artificial inoculation with a mixture of F. graminearum and F. culmorum. Treatments at the beginning of anthesis (BBCH 61) significantly reduced both FHB disease severity (up to 70%) and DON content (up to 90%) in the grain as compared to the inoculated control. Yields (tonne/ha) were higher in plots subjected to Prothioconazole treatments. Our findings show that the application of fungicides containing Prothioconazole provides a strong reduction of FHB disease caused by F. graminearum and F. culmorum, allowing an increase in grain yields and a considerable reduction of DON content in wheat kernels
Development of a scar markerfor the molecular identification of the fungus Fusarium semitectum.
No full textF. semitectum is a filamentous fungus showing remarkable characteristics, like the adaptability to a great range of hosts and environments and the unique metabolites production pattern. Its importance is proved by the crescent number of scientific papers published in the last years regarding this species. F. semitectum infections were reported in cotton, banana, alfalfa, melon, soybean. This fungus was also isolated from rice, but its pathogenicity still has to be proved. F. semitectum can produce fibrinolytic enzymes, mycotoxins (type A trichotecenes, zearalenone), antibiotics (equisetin, epi-equisetin) and a broad range of metabolites with antifungal (fusapyrone, deoxyfusapyrone) or zootoxic (beauvericin) activity.
In the present work we set up a new laboratory protocol for the molecular identification of this fungus. RAPD (Random Amplified Polymorphic DNA) technique was used to identify a species-specific amplification product. RAPD was combined with a fast DNA extraction method that generated reproducible band patterns. The selected fragment was cloned, sequenced and a primer pair (Fs1, Fs2) was developed to specifically detect F. semitectum using conventional PCR. The new SCAR marker was used to perform a mycological screening on rice, a species of great economical importance in Northern Italy
Differential gene expression during the pathogenic interaction between Pichia fermentans and peach fruit
No full textA biofilm-forming strain of Pichia fermentans was found to be a very strong antagonist against brown rot and grey mold in artificially wounded apple fruit when co-inoculated with either Monilinia fructicola or Botrytis cinerea, respectively. The same strain of yeast, however, was an aggressive pathogen when inoculated on peach fruit, causing rot of fruit tissues, even in the absence of other pathogens. Optical and scanning electron microscopy showed that P. fermentans produces only yeast-like shaped cells during colonization of apple tissue, while exhibiting pseudohyphal growth on peach tissue. A rapid subtractive hybridization approach (RaSH) was used to identify differentially expressed genes in the pathogenic form of P. fermentans by comparing the cDNA of P. fermentans sampled after 24 hours growth on apple with the cDNA of the same strain grown 24 hours on peach fruit. A total of 450 clones were analysed by a reverse Northern Blotting technique, yielding some fragments which were significantly expressed on peach but less on apple tissue. These sequences were compared to the available genome sequences of another dimorphic yeast, Candida albicans, and homologous genes were identified. The relationship between these genes, dimorphism, and pathogenicity will be discussed
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