Morphological characteristics of isolates of Colletotrichum spp.: Causal agents of anthracnose

Abstract

In the morphological studies were included isolates of Colletotrichum spp. originating from pear, apple and sour cherry fruits, as well as reference strains of C. acutatum (CBS 294.67) and C. gloeosporioides (CBS 516.97). The colony characteristics, appearance, shape and size of conidioma, appressoria, and conidia of isolates of Colletotrichum spp. were studied. The four morphological groups of colonies on PDA were observed, confirming the great phenotypic variability of isolates of Colletotrichum spp. Most isolates from apple and pear fruits (KC-6, KC-9, KC-12, JC-5, JC-7, JC-9), formed the first morphological group. The isolates from sour cherry (VC-3, VC-5, VC-7, VC-9) are separated in the fourth morphological group. The size and shape of conidia from these isolates fit the description of C. gloe­osporioides. The chromogenic isolates from pear (KC-21, KC-23, KC-82) formed the second morphological group, and in the third morphological group is isolate (JC-4) from apple fruit. The morphology of conidia from these isolates fit the description of C. acutatum. During this research were evident that all isolates formed conidioma - acervuli. The tested cultures of Colletotrichum spp. did not form teleomorpf. Because of outstanding variability, most of the studied characteristics cannot be independently applied as taxonomic criteria. Obtai­ned results showed that, for Colletotrichum species classification, at least two taxonomic criteria should be used: morphological features combined with molecular identification.

U morfološka ispitivanja su uključeni izolati Colletotrichum spp. poreklom sa plodova kruške, jabuke i višnje, kao i referentni sojevi C. acutatum (CBS 294.67) i C. gloeosporioides (CBS 516.97). Proučavanjem njihovih morfoloških karakteristika, dobijeni su podaci o izgledu ispitivanih kolonija, odlikama plodonosnog tela, apresorija, veličini i obliku konidija. Na podlozi KDA moguće je razlikovati četiri morfološke grupe kolonija, što potvrđu­je fenotipsku varijabilnost proučavanih izolata Colletotrichum spp. Većina izolata sa ploda kruške i jabuke (KC-6, KC-9, KC-12, JC-5, JC-7, JC-9) obrazuje prvu morfološku grupu. Izolati sa ploda višnje (VC-3, VC-5, VC-7, VC-9), su izdvojeni u četvrtu morfološku grupu. Veličina i oblik konidija ovih izolata odgovara opisu vrste C. gloeosporioides. Hromogeni izolati sa kruške (KC-21, KC-23, KC-82), obrazuju drugu morfološku grupu, a u trećoj morfološkoj grupi je izolat sa ploda jabuke (JC-4). Morfologija konidija ovih izolata odgovara opisu vrste C. acutatum. Tokom ovih istraživanja je utvrđeno da svi izolati obrazuju plodonosna tela - acervule. Testirane kulture Colletotrichum spp. ne formiraju teleomorfni stadijum. Zbog izražene varijabilnosti, većina ispitanih osobina ne mogu se primeni kao samostalni taksonomski kriterijum. Na osnovu dobijenih rezultata, za klasifikaciju vrsta roda Colletotrichum, potrebno je koristiti najmanje dva taksonomska kriterijuma: morfološke karakteristike uporedo sa molekularnom identifikacijom.