Diversidade de fungos endofíticos de cupuaçuzeiro (Theobroma grandiflorum (willd. ex spreng.) schum) e potencial para biocontrole de Moniliophthora perniciosa

Abstract

Cupuaçu (Theobroma grandiflorum) is a fruit tree native to the Amazon region and has great economic importance for local producers. However, its production is affected by pests and diseases, especially witches’ broom disease, caused by the fungus Moniliophthora perniciosa, which is considered the most important disease affecting this crop. In this context, endophytic fungi have emerged as a promising alternative for biological control, as they colonize plant tissues without causing apparent damage and may act against phytopathogens through mechanisms such as induced resistance, mycoparasitism, and antibiosis. This study aimed to investigate the diversity of endophytic fungi associated with cupuaçu plants and to evaluate their potential as biological control agents against M. perniciosa. Ten foliar samples from healthy and diseased plants were collected in production areas located in the municipalities of Manaus, Presidente Figueiredo, and Itacoatiara, Amazonas State, Brazil. Fungal isolation was performed on PDA medium, and isolates were grouped into morphotypes based on morphological characteristics. A total of 347 isolates were obtained, distributed into 13 genera belonging to the phylum Ascomycota, with predominance of the classes Sordariomycetes, Dothideomycetes, and Eurotiomycetes. The most frequent genera were Diaporthe (134 isolates), Colletotrichum (86), and Lasiodiplodia (50). Diversity analysis indicated higher richness in healthy plants from Itacoatiara (q0 = 10.0) and higher Shannon diversity in Presidente Figueiredo (q1 = 5.8). In the in vitro antagonism assay, some isolates showed high inhibition of mycelial growth of the pathogen, particularly Lasiodiplodia sp. (93.3%), Diaporthe sp. (91.1%), and Colletotrichum sp. (90.2%). These results indicate the promising potential of endophytic fungi associated with cupuaçu plants for the biological control of M. perniciosa.