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Tramesan, an eco-friendly approach against Septoria disease complex in wheat Wheat is the most cultivated cereal representing the main source of plant proteins in human food. However, up to 50% of worldwide wheat production may be lost because fungal diseases. The Septoria disease complex (STB) is critical, being Parastagonospora nodorum and Zymoseptoria tritici among the principal foliar pathogens on wheat. Currently, chemical fungicides (e.g. strobilurins, SDHI, triazoles and imidazoles) are widely used to challenge crop diseases. The chemicals may cause the insurgence of resistant fungal strains and, not less important, polluting the environment with possible toxic effects on humans and animals. The European Regulation 128/2009 aimed to control the use of pesticides ; de facto, this regulation eliminates several of them from the market. All this prompts the research to find eco-friendly novel alternatives to chemical pesticides ; in particular, agents based on living microorganism or natural products from them are studied to control plant diseases. One of the mechanisms of action of this novel bio compounds generation lays on the stimulation of plant defences ; this phenomenon is called "defence priming". It exploits natural ability of the plant immune system to act through inducible responses. Here we use purified and semi-purified Tramesan, a polysaccharide from the secretome of the basidiomycete Trametes versicolor, to assay its ability to prime wheat defences against septoriosis in greenhouse and field trials, under artificial and natural infection in three different crop seasons (2016-2017-2018). The results indicate that Tramesan is a promising solution to contrast the Septoria disease complex.

Different mycotoxins are usually biosynthesised during the morphological differentiation and the late phase of growth. Among them, ochratoxin A (OTA), patulin and aflatoxins represent a small but significant group produced for instance by Aspergillus ochraceus, Penicillium expansum and Aspergillus parasiticus as well A. flavus respectively. It was evidenced by many authors that cellular or environmental oxidative stress can represent a trigger, at least in Aspergillus flavus, A. parasiticus A. nidulans and Fusarium graminearum zearalenone and deoxynivalenol producer to induce the biosynthesis of different mycotoxins. From this scenario emerges that oxidative stress could represent a common trait in the formation of some mycotoxins. The activation of stress-related transcription factors such as yap 1 gene, perceiving oxidative stress in the fungal cell, triggers the synthesis of antioxidant-related enzymes modulating aflatoxins and OTA biosynthesis. -glucans and glycoproteins from the basidiomycetes Trametes versicolor and Lentinula edodes are able to stimulate yap 1 gene expression and to enhance the activity of the immune and antioxidant system in humans. The effect of -glucans on the inhibition of aflatoxin biosynthesis through the stimulation of antioxidant system (superoxide dismutase, catalase, glutathione peroxidase) of the fungal cells is evidenced. The results obtained are promising to control carcinogenic compounds such as mycotoxins in food and can constitute a safe tool to protect human and animal health by the use of “healing mushrooms”.

Mycotoxins are harmful secondary metabolites produced by a range of widespread fungi belonging in the main to Fusarium, Aspergillus and Penicillium genera. But why should fungi produce toxins? And how is the biosynthesis of these toxins regulated? Several separate factors are now known to be capable of modulating mycotoxin synthesis; however, in this study, focussing just on mycotoxins whose regulatory mechanisms have already been established, we introduce a further factor based on a novel consideration. Various different mycotoxin biosynthetic pathways appear to share a common factor in that they are all susceptible to the influence of reactive oxygen species. In fact, when a fungus receives an external stimulus, it reacts by activating, through a well-defined signal cascade, a profound change in its lifestyle. This change usually leads to the activation of global gene regulators and, in particular, of transcription factors which modulate mycotoxin gene cluster expression. Some mycotoxins have a clear-cut role both in generating a pathogenetic process, i.e. fumonisins and some trichothecenes, and in competing with other organisms, i.e. patulin. In other cases, such as aflatoxins, more than one role can be hypothesised. In this review, we suggest an "oxidative stress theory of mycotoxin biosynthesis" to explain the role and the regulation of some of the above mentioned toxins

A close correlation between lipoperoxide formation in cells ofAspergillus parasiticus and aflatoxin biosynthesis has been established in rich and poor media in which oxidative stress was induced by addition of cumene hydroperoxide, a lipoperoxidation inducer. The presence of hydroperoxides of linoleic acid inA. parasiticus mycelia was analysed by liquid chromatography-mass spectrometry (LC-MS). This relation appears to be driven by activation of certain oxidative stress related transcription factors, such asyap1-like,skn7-like andhsf2-like. Activation of these factors then leads to the promotion of transcription of genes encoding antioxidant-related enzymes, such as superoxide dismutase, catalase and glutathione peroxidase.The incomplete seavenging of intracellular oxidation inA. parasiticus cells can lead to aflatoxin biosynthesis. The relationship between oxidative stress and aflatoxin biosynthesis is indicated by the high correlation among increased activity of lipoperoxidation and the antioxidant defence system with formation of aflatoxins.With regard to the relationship of oxidative stress and aflatoxin biosynthesis, the mechanism of action of butylated hydroxyl anisole (BHA), an antioxidant compound, in the control of aflatoxin biosynthesis was also investigated. Results indicate this compound can act,per se, by inhibiting lipoperoxidation and by inducing antioxidative defence responses of the fungal cell.

The polymorphisms of the laccase genes (3 families) in mushrooms belonging to th Pleurotus genus (P. ostreatus, P. citrinopileatus, P. eryngii ; P. ferulae) were studied.

Pleurotus eryngii was considered to have to varietis, P. erynggii var. eryngii and P. eryngii var ferulae. The study of genoms of populations in different parts of Italy (Toscana, Lazio, Sardinia) has demonstrated that in nature in simpatric habitat the two vaieties do not cross-breed even if they are interfertile. Thus suggest that there is alredy the speciation between two vaietis.