Intra-species variability in Fusarium langsethiae strains in growth and T-2/HT-2 mycotoxin production in response to climate change abiotic factors

The objective of this study was to evaluate the potential intra-species variability of 3 Fusarium langsethiae strains in response to extreme climate change (CC) conditions on an oat-based matrix. The impact of elevated temperature (25 vs 30-34 °C) coupled with increasing drought stress (0.98 vs 0.95 aw) and elevated CO2 (400 vs 1000 ppm) were examined on lag phases prior to growth, growth rate, and production of the mycotoxins T-2 and HT-2 and their ratio. In comparison to the control conditions (25 °C; 0.98; 400 ppm), exposure to increased temperature (30-34 °C), showed similar reductions in the lag phase and fungal growth rates of all 3 strains. However, with elevated CO2 a reduction in both lag phases prior to growth and growth rate occurred regardless of the aw examined. For T-2 and HT-2 mycotoxin production, T-2 showed the most intra-species variability in response to the interacting abiotic stress factors, with the 3 strains having different environmental conditions for triggering increases in T-2 production: Strain 1 produced higher T-2 toxin at 25 °C, while Strain 2 and the type strain (Fl201059) produced most at 0.98 aw/30 °C. Only Strain 2 showed a reduction in toxin production when exposed to elevated CO2. HT-2 production was higher at 25 °C for the type strain and higher at 30-34 °C for the other two strains, regardless of the aw or CO2 level examined. The HT-2/T-2 ratio showed no significant differences due to the imposed interacting CC abiotic conditions.

De novo genome assembly and functional annotation for Fusarium langsethiae

MotivationFusarium langsethiae is a T-2 and HT-2 mycotoxins producing Fusarium species firstly characterised in 2004. It is commonly isolated from oats in Northern Europe. T-2 and HT-2 mycotoxins exhibit immunological and haemotological effects in animal health mainly through inhibition of protein, RNA and DNA synthesis. The development of a high-quality and comprehensively annotated assembly for this species is therefore essential in providing the molecular understanding and the mechanism of T-2 and HT-2 biosynthesis in F. langsethiae to help develop effective control strategies.ResultsThe F. langsethiae assembly was produced using PacBio long reads, which were then assembled independently using Canu, SMARTdenovo and Flye; producing a genome assembly total length of 59Mb and N50 of 3.51Mb. A total of 19,336 coding genes were identified using RNA-Seq informed ab-initio gene prediction. Finally, predicting genes were annotated using the basic local alignment search tool (BLAST) against the NCBI non-redundant (NR) genome database and protein hits were annotated using InterProScan. Genes with blast hits were functionally annotated with Gene [email protected] availabilityRaw sequence reads and assembled genome can be downloaded from: GenBank under the accession JAFFKB000000000

Use of the Secreted Proteome of Trametes versicolor for Controlling the Cereal Pathogen Fusarium langsethiae

Fusarium langsethiae is amongst the most recently discovered pathogens of small grains cereals. F. langsethiae is the main producer, in Europe, of T2 and HT-toxins in small grain cereals, albeit often asymptomatic; this makes its control challenging. The European Union (EU) is pushing hard on the use of biocontrol agents to minimize the use of fungicides and pesticides, which are detrimental to the environment and responsible for serious pollution of the soil and superficial water. In line with EU directives (e.g., 128/2009), here we report the use of protein fractions, purified from the culture filtrate of the basidiomycete Trametes versicolor, for controlling F. langsethiae. T. versicolor, a so-called medicinal mushroom which is applied as a co-adjuvant in oncology and other pathologies as a producer of biological response modifiers. In this study, the exo-proteome of T. versicolor proved highly efficient in inhibiting the growth of F. langsethiae and the biosynthesis of the T2 toxin. Results are promising for its future use as a sustainable product to control F. langsethiae infection in cereals under field conditions.

T-2 i HT-2 toksini u hrani i hrani za životinje

Mikotoksini su sekundarni metaboliti plijesni koji imaju toksičan učinak na zdravlje ljudi i životinja. Smatraju se neizbježnim onečišćivačima hrane i hrane za životinje, a predstavljaju problem u cijelom svijetu jer se njihova koncentracija ne smanjuje ni nakon uobičajenih postupaka prerade hrane. T-2 toksin i njegov glavni metabolit HT-2 pripadaju velikoj grupi trihotecenskih mikotoksina. T-2 toksin se smatra najtoksičnijim predstavnikom trihotecenskih mikotoksina tipa A, a proizvode ga plijesni roda Fusarium, načešće Fusarium langsethiae, Fusarium poae i Fusarium sporotrichioides. Međunarodna agencija za istraživanje raka (IARC) je uvrstila T-2 toksin u skupinu 3, među spojeve koji se ne mogu klasificirati kao ljudski karcinogeni. Ipak, izraženo citotoksično, imunosupresivno i hematotoksično djelovanje T-2 i HT-2 toksina može uzrokovati kronične bolesti kod ljudi i životinja. Daljnja istraživanja ovih mikotoksina su nužna s obzirom na nedostatak toksikoloških podataka te kako bi se odredila njihova prisutnost u hrani i hrani za životinje i efikasne metode dekontaminacije onečišćenih sirovina i proizvoda. Kako bi se izbjegli negativni učinci T-2, HT-2 toksina i ostalih trihotecenskih mikotoksina na zdravlje ljudi i životinja, važno je sprječavanje rasta plijesni i sustavan nadzor sirovina i finalnih proizvoda namijenjenih prehrani ljudi i hranidbi životinja.