Diverzitet kompleksa vrste Fusarium graminearum patogena strnih žita i kukuruza u Srbiji

Abstract

Za proučavanje diverziteta vrste F. graminearum odabran je 101 izolat izkolekcije Laboratorije za fitopatologiju Instituta za kukuruz "Zemun Polje" koji suprethodno identifikovani konvencionalnim metodama na osnovu makroskopskih imikroskopskih svojstava. Izolati su prikupljeni u periodu od 1993. do 2015. godine, aporeklom iz uzoraka pšenice (42), kukuruza (37) i ječma (22) iz 41 lokaliteta nateritoriji Srbije. Sa ciljem da se dobije uvid o rasprostranjenosti, prisustvu i diverzitetuvrsta Fusarium graminearum kompleksa (Fg) kao i o trihotecenskim hemotipovima uSrbiji, obavljena su proučavanja morfoloških, patogenih, toksigenih i filogenetskihsvojstava odabranih izolata. Na osnovu svih proučenih svojstava utvrđeno je prisustvotri vrste u okviru Fg kompleksa: Fusarium graminearum sensu stricto, Fusariumboothii i Fusarium vorosii. Po prvi put u Srbiji, detektovano je prisustvo F. boothii i F.vorosii patogena strnih žita i kukuruza u našoj zemlji.Na osnovu morfoloških, patogenih i toksigenih svojstava uočen je velikidiverzitet ispitivanih izolata. Rezultati analize morfoloških svojstava izolata F.graminearum ss, F. boothii i F. vorosii, ukazuju da ne postoje razlike među njima.Izolati vrste F. boothii i F. vorosii ispoljili su generalno slabiju patogenost u poređenjusa ostalim izolatima. Analiza potencijala produkcije mikotoksina deoksinivalenola izearalenona ELISA i HPLC metodom ukazala je na varijabilnost između ispitivanihizolata. Određivanjem trihotecenskih hemotipova hemijskom analizom utvrđeno je da uSrbiji postoje dva hemotipa - 15ADON (dominantan) i 3ADON.Za razliku od hemijskih, molekularnim analizama na osnovu TRI3 i TRI12 gena,utvrđeno je prisustvo samo 15ADON hemotipa. Dobijeni rezultati o biodiverzitetuhemotipova su prvi nalaz u agroekološkim uslovima Srbije. Analiza nukleotidnihsekvenci tri genomska regiona (TEF−1α, β−tubulin i histon H3), pokazala je da postojerazličiti potencijali za razdvajanje vrsta u okviru Fg kompleksa. Rezultati ove disertacijeukazali su na postojanje dve vrste u okviru Fg kompleksa (F. boothii i F. vorosii), kojedo sada nisu identifikovane na teritoriji Srbije. Sekvenciranje ovih genomskih regionaodabranih izolata i njihovo poređenje sa referentnim izolatima kao i poređenje saizolatima Fg kompleksa u svetu doprinelo je boljem poznavanju biodiverziteta ovihvrsta u Srbiji.

One hundred and one isolates of the F. graminearum species have been isolatedfrom the collection of the Laboratory of Phytopathology of the Maize ResearchInstitute, Zemun Polje to study the species diversity. These isolates had been previouslyidentified using conventional methods based on macroscopic and microscopicproperties. Isolates, originating from samples of wheat (42), maize (37) and barley (22),were collected from 41 locations in Serbia in the period from 1993 to 2015. In order togain insight into the distribution, presence and diversity of the Fusarium graminearumspecies complex (Fg), as well as into thrichotecene chemotypes in Serbia, studies of themorphological, pathogenic, toxigenic and phylogenetic properties of the selectedisolates were carried out. According to all observed properties, the presence of the threefollowing species was determined within the Fg complex: Fusarium graminearumsensu stricto, Fusarium boothii and Fusarium vorosii. F. boothii and F. vorosii,pathogens of small grains and maize in our country, were detected for the first time inSerbia.Based on morphological, pathogenic and toxigenic properties, a great diversityof analysed isolates was observed. Results of analyses of morphological properties ofthe isolates of F. graminearum ss, F. boothii and F. vorosii, pointed out that there hadbeen no differences among them. Isolates of F. boothii and F. vorosii species exhibitedgenerally less pathogenicity than remaining isolates. The analysis of the potential for theproduction of mycotoxins deoxynivalenol and zearalenone by the ELISA and the HPLCmethod pointed out to the variability among analysed isolates. The determination oftrichothecene chemotypes done by chemical analyses confirmed the presence of twochemotypes in Serbia- 15ADON (dominant) and 3ADON. In contrast to chemicalanalyses, the molecular analyses, based on the TRI3 and TRI12 genes, established thepresence of only 15ADON chemotype. The obtained results on the biodiversity ofchemotypes are the first finding under agroecological conditions of Serbia. The analysisof nucleotide sequences of the three genomic regions (TEF−1α, β−tubulin and histoneH3), showed the existence of different potentials for separation of species within the Fgcomplex. The results presented in this PhD thesis point out to the existence of twospecies (F. boothii and F. vorosii) within the Fg complex, which have not yet beenidentified in the territory of Serbia. Sequencing these portions of the genome of theselected isolates and their comparison with the reference isolates, as well as, thecomparison with the Fg complex isolates in the world contributed to a better knowledgeof the biodiversity of these species in Serbia.