Karakterizacija vrsta roda Colletotrichum, prouzrokovača antraknoze lucerke u Srbiji i osetljivost genotipova

Abstract

U periodu 2005-2010. godine, pregledom 17 lokaliteta gajenja lucerke u Srbiji, zabeležena je pojava intenzivnih simptoma antraknoze na lucerki. Učestalost zaraze u ispitivanim usevima bila je visoka i dostizala je 30%. Sa ciljem da se rasvetli etiologija oboljenja i ispita uticaj gljiva roda Colletotrichum obavljena je analiza 150 uzoraka, dobijeno ukupno 80 izolata i 18 odabrano je za morfološku, biološku i molekularnu identifikaciju i analizu vegetativne kompatibilnosti. Na osnovu obavljenih istraživanja ustanovljeno je prisustvo tri vrste roda Colletotrichum na lucerki u Srbiji: C. trifolii, C. destructivum i Colletotrichum sp.-Coll-44. Sve proučavane osobine ispitivanih izolata analizirane su kao mogući taksonomski kriterijum za razlikovanje vrsta roda Colletotrichum. Na osnovu dobijenih rezultata, za razvrstavanje vrsta preporučuje se uporedno korišćenje najmanje dva taksonomska kriterijuma, morfoloških osobina i molekularne karakterizacije. Analize nukleotidnih sekvenci tri genomna regiona, ITS region rDNK, intron gena GS i intron gena GPHD, pokazale su različit potencijal za preciznije razdvajanje vrsta roda Colletotrichum. Rekonstrukcijom tri filogenetska stabla dat je doprinos u rasvetljavanju filogenetske meñupovezanosti vrsta prisutnih u Srbiji sa ostalim vrstama ovog roda iz različitih delova sveta. Proučavanjem genetičkog diverziteta populacija C. trifolii, C. destructivum i Colletotrichum sp. izolat Coll-44, ukupno 18 monosporijalnih izolata svrstano je u sedam grupa vegetativne kompatibilnosti. Ova istraživanja ukazala su na postojanje genetičke varijabilnosti komercijalnih sorti lucerke u osetljivosti prema ispitivanim izolatima u kontrolisanim uslovima inokulacije, sa prevalentnim vrstama C. trifolii i C. destructivum. Genotipovi sa najnižim ispoljenim nivoom osetljivosti koristiće se u programima selekcije lucerke na otpornost.

During the period of 2005-2010, a survey was conducted at 17 localities in Serbia and intense occurrence of alfalfa anthracnose was observed. The disease incidence in the tested crops was high and it reached 30%. With the aim to clarify the etiology of the disease and investigate the effect of Colletotrichum, 150 samples were analysed. Total of 80 isolates were obtained, among which 18 were selected for morphological, biological and molecular characterization and analysis of vegetative compatibility. The conducted research showed the presence of three species of Colletotrichum on alfalfa in Serbia: C. trifolii, C. destructivum and Colletotrichum sp. isolate Coll-44. All studied traits of the tested isolates were analyzed as a possible taxonomic criterion for distinguishing species of the genus Colletotrichum. Based on these results, for the identification of species, it is recommended to use at least two parallel taxonomic criteria, morphological traits and molecular characterization. Analysis of nucleotide sequences of the three genome regions, ITS region of rDNA, GS gene intron and GPHD gene intron, showed different potential for more precise Colletotrichum species separation. By reconstructing three phylogenetic trees, the contribution was given to the establishing the phylogenetic relationships among species present in Serbia, with other species from diferent parts of the world. By studying the genetic diversity of populations of C. trifolii, C. destructivum and Colletotrichum sp. isolate Coll-44, 18 monosporial isolates were distributed into seven vegetative compatibility groups. The studies revealed the existence of different levels of susceptibility with in commercial cultivars against tested isolates of prevalent species, C. trifolii and C. destructivum. Genotypes with the lowest susceptibility will be used in selection programs and improving alfalfa for resistance.