Candida krusei and Kloeckera apis inhibit the causal agent of pineapple fusariosis, Fusarium guttiforme Adriana M. N. KORRES a , David S. BUSS b , Jos  e A. VENTURA c , Patricia M. B. FERNANDES b, * a Instituto Federal de Educac ¸ ~ ao, Ci^ encia e Tecnologia do Esp  ırito Santo (IFES), Av. Vit oria, 1729, Vit oria, ES, Brazil b N ucleo de Biotecnologia, Universidade Federal do Esp  ırito Santo (UFES), Av. Marechal Campos, 1440, Maruipe, Vit oria, ES, Brazil c Instituto Capixaba de Pesquisa, Assist^ encia T ecnica e Extens~ ao Rural (INCAPER), Rua Afonso Sarlo 160, Vit oria, ES, Brazil article info Article history: Received 7 April 2011 Received in revised form 31 August 2011 Accepted 7 September 2011 Available online 29 September 2011 Corresponding Editor: Stephen W. Peterson Keywords: Antagonist yeasts Biocontrol Microbial interactions abstract Studies based on microbial ecology and antagonistic interactions play an important role in the development of new alternative strategies in controlling plant pathogens and are relevant to further biotechnological applications. Antagonistic interactions between the yeasts Candida krusei and Kloeckera apis isolated from rotten pineapple fruits, and two isolates of the patho- genic filamentous fungus Fusarium guttiforme (Syn.: Fusarium subglutinans f. sp. ananas) resis- tant and susceptible to fungicide benzimidazole were studied in broth culture, and on plate assays. The yeasts significantly reduced Fusarium conidial germination after 24 h of cocultiva- tion in broth culture, and also mycelial growth on plate assays. Slide coculture appeared to show attachment of yeasts to the hyphal surface and also slight morphological abnormalities caused by C. krusei. Filtrates of cocultures of fungi and yeasts inhibited fungal growth, but fil- trates of the yeast cultures alone did not, suggesting that the antagonistic action of the yeasts is inducible. The F. guttiforme isolate sensitive to benzimidazole was most affected by both yeasts in pine- apple juice, reaching a maximum of 36.5 % germ tube inhibition. This isolate was also in- hibited by yeasts in mycocinogenic plate assay. These results demonstrated that C. krusei and K. apis are effective in inhibiting F. guttiforme growth and that the mode of action is as- sociated with hyperparasitism and mycocinogenic activity. ª 2011 British Mycological Society. Published by Elsevier Ltd. All rights reserved. Introduction Brazil is a tropical country with great potential for the export of fruit to many regions of the world. In this context, pineapple is commercially very significant and Brazil is the number one world producer with almost 2 500 000 ton y 1 (FAO 2009). How- ever, plant and fruit diseases are major problems in field and postharvest conditions and fusariosis, caused by the fungus Fusarium guttiforme (Syn.: Fusarium subglutinans f. sp. ananas) is a constant concern in crops, leading to 30e40 % losses of fruit and 15e20 % losses of propagative material (Ventura et al. 2009). This fungus infects pineapple plants and fruits with the characteristic symptoms being morphological changes in dis- eased plants and exudation of gum from infected fruits (Ventura & Zambolim 2002). Chemical control is recommended, but constant use of systemic benzimidazole fungicides has se- lected resistant isolates of the pathogen (Ventura et al. 1994; Santos et al. 2002). In natural environments microbial interactions exert both beneficial and harmful effects on pathogen populations and some microorganisms act as natural biocontrol agents (Saligkarias et al. 2002; Hiltunen et al. 2009). Studies of microbial * Corresponding author. Tel.: þ55 27 3335 7348. E-mail addresses: akorres@gmail.com, dsbuss@gmail.com, ventura@incaper.es.gov.br, patricia.fernandes@pq.cnpq.br journal homepage: www.elsevier.com/locate/funbio fungal biology 115 (2011) 1251 e1258 1878-6146/$ e see front matter ª 2011 British Mycological Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.funbio.2011.09.001