Combined effect of beauvericin and T-2 toxin on antioxidant defence systems in cherry tomato shoots

During their life cycle, plants can undergo simultaneous attack by different pathogens that produce various toxins. It is well known that in some plant-fungal interactions, mycotoxins play an important role in pathogenesis and induce a reactive oxygen species (ROS) increase. Plants counteract the over-accumulation of ROS by reinforcing the defence systems. T-2 toxin (T-2) and beauvericin (BEA) mycotoxins are produced by some Fusarium species and have different chemical structures, mechanisms of action and biological activities. In this study, the individual and combined effects of the two toxins on defence systems such as the ascorbate-glutathione cycle and peroxidases were evaluated in cherry tomato shoots. Hydrogen peroxide content as an index of oxidative stress was also measured. Inhibitory effects on ascorbate peroxidase, dehydroascorbate reductase and ascorbate, and stimulatory effects on glutathione reductase, monodehydroascorbate reductase and reduced glutathione were observed when tomato plants were simultaneously treated with BEA and T-2. The trends of these biochemical parameters highlight the presence of a range of defence mechanisms activated by plants in response to mycotoxins. The interaction between BEA and T-2 resulting in synergistic and/or antagonistic effects on the studied defence systems is also discussed. It is concluded that the effects of these mycotoxins alone are not predictive of their combined effects

Miscele eutettiche come solventi biocompatibili a basso impatto ambientale per l’estrazione e la determinazione di metaboliti secondari fungini in matrici alimentari

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Molecular characterization of Pleurotus eryngii varieties occurring in Italy

The Pleurotus eryngii species complex is an economically important group which includes several closely related varieties, whose genetic discrimination is still not clear. One hundred and ten Italian strains of Pleurotus eryngii belonging to the varieties elaeoselini, eryngii, ferulae and thapsiae and P. nebrodensis were analysed by sequencing two housekeeping genes (ef1-a and rpb2), in order to find molecular markers for the identification of different varieties. Sequence analysis of partial ef1-a and rpb2 genes, allowed identification of some conserved nucleotide positions within each variety but variable among var. elaeoselini, var. eryngii, var. ferulae var. thapsiae and P. nebrodensis, allowing their discrimination. Phylogenetic analysis from the data of the two genes data set showed that var. elaeoselini, var. thapsiae, var. ferulae and var. eryngii are closely related to each other, and confirm P. nebrodensis as a separate clade

Risk assessment of the occurrence of black aspergilli on grapes grown in an alpine region under a climate change scenario

Members of the Aspergillus section Nigri, also known as black aspergilli, are responsible for the ochratoxin A (OTA) and fumonisins contamination of wine. The presence of black aspergilli in vineyards has been investigated extensively in warm climates, in which the incidence of these aspergilli on grapes and levels of OTA contamination of wines are commonly high. However, a detailed description of black aspergilli populations is needed in wine-producing cool regions to establish a baseline in view of the strengthening of temperature increase and in case of summer rainfall decrease. With this in mind, we isolated and characterized black aspergilli from grapes grown in an alpine region in Northern Italy (Trentino) during a 3-year sampling. Black aspergilli were isolated from around 10 % of the grape berries and most of the isolates were classified as A. niger, A. tubingensis and A. uvarum. A. carbonarius was isolated only once. OTA production was detected only in the A. carbonarius isolate and in one A. niger. Most of A. niger isolates were able to produce fumonisins. The presence of mycotoxins biosynthesis genes was assessed in A. niger isolates. An15g07920, a polyketide synthase (PKS) gene involved in OTA biosynthesis, was detected by PCR only in the single ochratoxigenic isolate. This strong correlation was not observed for anfum1, anfum6 and anfum8, three genes included in the A. niger fumonisin biosynthesis gene cluster, which were detected in different A. niger isolates not able to produce fumonisins. Projections of mean daily temperatures and monthly rainfall indicate that the presence of black aspergilli on grapes grown in vineyards of these valleys will probably increase in the future

Ecology and biotechnology of thermophilic fungi on crops under global warming

This chapter considers how global warming will change fungi in the environment to those that grow at high temperatures. Biotechnology will be affected (a) positively, by creating thermotolerant and thermophilic fungi (TTF), which have novel applied properties, and (b) negatively, in that useful fungi may disappear. The chapter indicates how this could happen and what the novel properties may be. Overall, the purpose is to increase awareness of the issue of global warming changing the paradigm and pointing out the potential loss of the current diversity of fungi with biotechnological potential. The change in fungi that is occurring now is well illustrated by mycotoxigenic fungi. Underpinning the diversity of fungi is correct nomenclature which is discussed. A major threat from certain fungi is mycotoxin contamination of crops, which are known agents of diseases for humans and animals. Plant diseases of crops in general are frequently caused by fungi. Climate change will lead to more extreme climate and an increase in temperature is predicted in which many fungi will adapt to grow. The higher temperatures are leading to increases in aflatoxin contamination of crops which are the most dangerous mycotoxins. Crops will be challenged severely threatening the sustainability of the human food supply. However, by extension, temperatures are likely to go beyond the optimum growth for aflatoxigenic fungi which could become extinct in tropical regions with high aflatoxin contamination in food. Succeeding thermotolerant and thermophilic fungi (TTF) may produce novel mycotoxins. Fungi with useful biotechnological properties (e.g. pharmaceuticals, enzymes, organic acids) found in the environment could be lost or found. The only conventional mycotoxin produced by TTF is patulin; and could this mycotoxin dominate aflatoxin? In addition, TTF may increase diseases of tropical plants as illustrated with Ganoderma disease of oil palm, the plant that produces valuable palm oil. The TTF may have unique biotechnological properties such as the ability to produce high-temperature enzymes. Novel white rot fungi may evolve from the Ganoderma fungi that rot oil palm, leading to novel lignocellulose-degrading enzymes capable of operating at high temperatures. The results of this current work indicated that novel opportunities may arise for biotechnology with climate change although the overall effect will be detrimental to areas related to plant pathology. The chapter considers the ecological and biotechnological implications of these possibilities.Portuguese Foundation for Science and Technology (FCT). It was within the strategic funding of UID/BIO/04469/2013 unit, COMPETE 2020 (POCI-01-0145-FEDER-006684) and BioTecNorte operation (NORTE-01-0145-FEDER-000004), which was funded by the European Regional Development Fund within Norte2020—Programa Operacional Regional do Norte. RRMP received gratefully the IOI Professorial Chair in Plant Protection for 2018 at the Universiti Putra Malaysiainfo:eu-repo/semantics/publishedVersio