Učestalost toksigenih vrsta Fusarium i fuzariotoksina u zrnu pšenice u Srbiji

A total of 88 and 40 wheat samples collected immediately prior to harvest in 2005 and 2006, respectively, under different agroecological conditions, were studied in respect to the occurrence of Fusarium spp. and the production of fusariotoxins. The greatest number of samples was infected with species of the genera Fusarium (81.8 and 65.0%), and Alternaria (36.3 and 17.5%) with the intensity ranging from 9.4 to 84.0% in 2005 and from 23.4 to 80.6% in 2006. Out of 13 identified species belonging to the genus Fusarium, F. graminearum had the highest frequency (35.2 and 12.5%) and the intensity up to 67.2%, and 21.9%, in 2005 and 2006, respectively, followed by F. poae but only in 2005 (20.4%), and F. proliferatum in 2006 (19.7%). The natural occurrence of mycotoxins in positive samples varied from 37 to 331 ppb for zearalenone and from 31 to 125 ppb for diacetoxyscirpenol (DAS) and T-2 toxin. The concentration of mycotoxins amounted, on average, to 133.4, 61.0 and 45.7 ppb for zearelenone, DAS and T-2 toxin, respectively.Osamdeset osam i 40 uzoraka pšenice, prikupljenih neposredno pred žetvu u 2005. i 2006. godini u različitim agroekološkim uslovima u Srbiji proučavani su radi praćenja pojave Fusarium spp. i stvaranja fuzariotoksina. Najveći broj uzoraka bio je zaražen vrstama roda Fusarium (81,8 i 65,0%), a zatim sa Alternaria spp. (36,3 i 17,5%) sa intenzitetom 9,4-84,0% u 2005. i 23,4-80,6% u 2006. godini. Od ukupno 13 identifikovanih vrsta iz roda Fusarium najučestalija je bila F. graminearum (35,2 i 12,5%) sa intenzitetom do 67,2% u 2005. i do 21,9% u 2006. godini, a zatim F. poae, ali samo u 2005. godini (20,4%), i F. proliferatum u 2006. godini (19.7%). Prirodna pojava mikotoksina u pozitivnim uzorcima je varirala od 37 do 331 ppb za zearalenon i od 31 do 125 ppb za diacetoksiscirpenol (DAS) i T-2 toksin. U proseku, koncentracija mikotoksina je bila 133,4 ppb za zearelonon, 61,0 ppb za DAS i 45,7 ppb za T-2 toksin

Toksigeni potencijal izolata Fusarium poae poreklom sa pšenice

Eleven isolates of F. poae, originated from wheat grain at 9 locations mainly in Vojvodina, were encompassed by the present study. The greatest number of samples was collected in 2005, in which the climatic conditions favoured a more intensive occurrence of Fusarium ear blight of wheat. In order to determine toxicological potential of this species, cultures of the selected isolates were grown in liquid media (GPY and SPY) on a rotary shaker (180 revolutions min-1), at room temperature (21-26°C) for three days. Crude toxins were isolated from liquid culture filtrates of isolates by the use of ethyl acetate, while quantification of mycotoxins was done by the thin layer chromatography method. A liquid culture of the isolate GZ-LES (F. graminearum) was used as a control for the evaluation of the zearalenone biosynthesis potential. On the other hand, the liquid culture of the isolate KF-38/1 (F. sporotrichioides) was used as a control for both type-A trichothecenes (T-2 toxin and diacetoxyscirpenol - DAS). The obtained results show that F. poae, in contrast to F. graminearum, has no potential for the zearalenone biosynthesis. The presence of DAS was determined only in one isolate of F. poae (MRIZP-666), and in the control isolate of F. sporotrichioides (KF-38/1/R), that were grown in the GPY liquid medium. The T-2 toxin was detected in the isolate MRIZP-666, grown in both media, and in the isolates MRIZP-37 and MRIZP-860, cultured in the GPY and SPY liquid medium, respectively. The control culture KF-38/1/R (F. sporotrichioides) produced the T-2 toxin at the concentration of 4,000 μg L-1. According to the gained information, it can be concluded that the potential of F. poae for the type-A trichothecene biosynthesis was low, as the concentration of DAS or T-2 toxin did not exceed 80 μg L-1 or 240 μg L-1, respectively.U ovom radu je u in vitro uslovima proučena sposobnost izolata F. poae za biosintezu jedne grupe fuzariotoksina - trihotecena tipa A (T-2 toksin i diacetoksiscirpenol - DAS), kao i zearalenona (ZEA). Toksikološki profil ove vrste je kod nas nedovoljno ispitan s obzirom na njenu zastupljenost i toksigena svojstva prema literaturnim podacima. Proučavanjima je bilo obuhvaćeno 11 izolata F. poae, poreklom sa pšenice iz 9 lokaliteta, uglavnom sa područja Vojvodine. Najveći broj uzoraka prikupljen je 2005. godine, kada su klimatski uslovi pogodovali intenzivnijoj pojavi fuzarioza klasa ove poljoprivredne kulture. Za određivanje toksikološkog potencijala F. poae kulture odabranih izolata su gajene u tečnim podlogama (GPK i SPK) tokom 3 dana na sobnoj temperaturi (21-26°C) i na rotacionoj tresilici (180 obrtaja min-1). Sirovi toksini su izolovani iz filtrata tečnih kultura ispitanih izolata pomoću etil acetata, dok je kvantifikacija mikotoksina izvršena metodom tankoslojne hromatografije. Tečna kultura izolata GZ-LES (F. graminearum) je korišćena kao kontrolna kultura za utvrđivanje potencijala za biosintezu zearalenona, a KF-38/1/R (F. sporotrichioides) za oba trihotecena tipa A (T-2 toksin i DAS). Dobijeni rezultati pokazuju da F. poae, za razliku od F. graminearum, ne poseduje potencijal za biosintezu zearalenona. Prisustvo DAS-a je utvrđeno samo kod jedne kulture F. poae (MRIZP-666) i kontrolnog izolata F. sporotrichioides (KF-38/1/R) koji su gajeni u tečnom GPK medijumu. T-2 toksin je detektovan kod izolata MRIZP-666 pri gajenju u obema podlogama, kao i izolata MRIZP-37 u GPK, odnosno MRIZP-860 u SPK medijumu. Kontrolna kultura KF-38/1/R (F. sporotrichioides) proizvodila je T-2 toksin u koncentraciji od 4000 μg L-1. Na osnovu iznetih podataka može se zaključiti da je potencijal F. poae za biosintezu trihotecena tipa A bio nizak u datim uslovima s obzirom da koncentracija DAS-a nije prelazila 80 μg L-1, odnosno T-2 toksina 240 μg L-1. Imajući u vidu prikazane rezultate, smatramo da je za dobijanje konačnog odgovora na pitanje o toksikološkom profilu izolata F. poae u Srbiji neophodno preduzeti dodatna ispitivanja, ne samo sa novim izolatima iz godina koje slede, nego i u drugim uslovima kultivisanja, u prvom redu na sterilnom prirodnom supstratu kao što su pšenica i kukuruz

Le Grand écho du Nord de la France

16 juillet 18911891/07/16 (A73,N197).Appartient à l’ensemble documentaire : NordPdeC

Frequency of toxigenic Fusarium species and fusariotoxins in wheat grain in Serbia

A total of 88 and 40 wheat samples collected immediately prior to harvest in 2005 and 2006, respectively, under different agroecological conditions, were studied in respect to the occurrence of Fusarium spp. and the production of fusariotoxins. The greatest number of samples was infected with species of the genera Fusarium (81.8 and 65.0%), and Alternaria (36.3 and 17.5%) with the intensity ranging from 9.4 to 84.0% in 2005 and from 23.4 to 80.6% in 2006. Out of 13 identified species belonging to the genus Fusarium, F. graminearum had the highest frequency (35.2 and 12.5%) and the intensity up to 67.2%, and 21.9%, in 2005 and 2006, respectively, followed by F. poae but only in 2005 (20.4%), and F. proliferatum in 2006 (19.7%). The natural occurrence of mycotoxins in positive samples varied from 37 to 331 ppb for zearalenone and from 31 to 125 ppb for diacetoxyscirpenol (DAS) and T-2 toxin. The concentration of mycotoxins amounted, on average, to 133.4, 61.0 and 45.7 ppb for zearelenone, DAS and T-2 toxin, respectively

Analysis of genetic diversity among Macrophomina phaseolina (Tassi) Goid. isolates from Euro-Asian countries

The study assessed the genetic variability among Macrophomina phaseolina (Tassi) Goid. isolates originating from six different countries (Turkey, Bulgaria, Romania, Spain, Ukraine and Serbia), collected mostly from sunflower, but also maize, soybean, flax, common bean and zebra plant. RAPD analysis was based on 154 polymorphic bands obtained with 14 OPA primers. RAPD markers OPA-02-OPA-05, OPA-07-OPA-13 and OPA-18-OPA-20 were found to be suitable for measuring the genetic relatedness and detecting variability in M. phaseolina populations. Cluster analysis revealed high genetic diversity of M. phaseolina isolates within the same country of origin, but clear differentiation according to the isolates' host plant and geographical origin was not observed. Contingency analysis and corrected contingency coefficients enabled determination of RAPD markers associated with geographical origin of isolates, as well as markers specific for non-sunflower isolates. Marker OPA 10_1750 was found to be highly specific for the isolates from Turkey, while two markers, OPA 3_1250 and OPA 9_800, could be used for differentiation of isolates originating from sunflower from isolates originating from other host plants