Identification of clonostachys and trichoderma spp. from banana fruit surfaces by cultural, morphological and molecular methods

Abstract

Species of Clonostachys and Trichoderma isolated from the surface of bananas were highly antagonistic to crown rot- causing fungal pathogens of banana, such as Lasiodiplodia theobromae, Thielaviopsis paradoxa, Colletotrichum musae, and Fusarium verticillioides. Cultural and morphological examinations revealed that the fungal antagonists were similar to C. byssicola and T. harzianum, with some characters overlapping with closely related species.Molecular identification is recommended since the fungal isolates could not be differentiated adequately by cultural and morphological methods. Accurate taxonomy of these fungal antagonists was essential for the subsequent biological control studies. The tub2 region of β-tubulin genes of Clonostachys and 5.8S rDNA with the ITS regions of Trichoderma isolates were analyzed to determine their phylogenic placement. Molecular and phylogenetic analyses revealed 100% homology of Clonostachys (accession number AB308539) to C. byssicola (accession number AF358154) and 99% identity of Trichoderma (AB308540) to T. harzianum (accession number AY625068, AF443927). The identity of the fungal isolates was confirmed as Clonostachys byssicola Schroers and Trichoderma harzianum Rifai. © 2011 Mycological Society of China.