Molluscicidal Screening of Hypocreales Fungi from a Brazilian Cerrado Cave Against Biomphalaria glabrata Snails

Abstract

Fungi play vital roles in ecosystems through parasitism, commensalism, and mutualism. Additionally, they are widely used in industry as bioactive compound producers and biological control agents. Biomphalaria glabrata is a freshwater snail often controlled with chemical molluscicides. However, developing effective alternatives to these chemical treatments is essential. This study evaluated the molluscicidal potential of culture supernatant from Hypocreales fungi isolated from a cave in the Brazilian Cerrado against the B. glabrata. The isolates were identified based on morphological features and ITS rDNA sequences. Fifteen filtrates of Hypocreales fungi were obtained and tested both pure and in different dilutions (10% and 50%) against newly hatched snails during 96 h of exposure. The fungal isolates were identified as belonging to the genera of Clonostachys (1), Cylindrocladiella (1), Fusarium (1), Gliocladiopsis (1), Keithomyces (1), Marquandomyces (1), Ovicillium (1), Pochonia (1), Purpureocillium (1), Sarcopodium (1), Sarocladium (1), Trichoderma (3), and Volutella (1). The results showed 93.33% (14) of the fungal filtrates induced significant mortality, indicating their molluscicidal activity, with Pochonia chlamydosporia FCCUFG 100 and Volutella aeria FCCUFG 107 causing 100% mortality in all dilutions. These results reveal the potential of Hypocreales fungi from a Brazilian Cerrado cave as a promising approach for snail control.

Keywords: biotechnological potential; cave mycodiversity; fungal bioprospecting; fungal filtrate; gastropod control.

Figure 1

Maximum likelihood (ML) tree using ITS rDNA sequences representing 13 genera of Hypocreales fungi from a cave in the Brazilian Cerrado. Fungal isolates obtained in this study are in bold. Confidence values for ML-BS ≥ 70% are shown near the nodes, and the scale bar represents the expected number of changes per site. The tree was rooted to Graphium penicillioides CBS 102632 (Microascales).

Figure 2

Mortality rates (means ± standard deviation) of Biomphalaria glabrata newly hatched snails exposed to (a) niclosamide at 50% lethal concentration (LC₅₀) and (b) culture medium (PDB) after 96 h. NC = negative control group composed of reconstituted water.

Figure 3

Cumulative mortality (%) of Biomphalaria glabrata newly hatched snails from the negative control (NC) and after exposure to filtrates diluted to 10% (FF10) and 50% (FF50) and undiluted fungal filtrates (FF) for 96 h. The experiment used fungal filtrates produced by isolates representing 13 genera of Hypocreales fungi from a cave in the Brazilian Cerrado.

Figure 4

Cumulative mortality (%) of newly hatched Biomphalaria glabrata snails from the negative control group (NC) and exposure to filtrates diluted to 10% (FF10) and 50% (FF50) and undiluted fungal filtrates (FF) during 96 h. The experiment used fungal filtrates produced by isolates representing 13 genera of Hypocreales fungi from a cave in the Brazilian Cerrado. (a) Clonostachys sp. FCCUFG 93. (b) Cylindrocladiella sp. FCCUFG 94. (c) Fusarium sp. FCCUFG 95. (d) Gliocladiopsis elghollii FCCUFG 96. (e) Keithomyces sp. FCCUFG 97. (f) Marquandomyces marquandii FCCUFG 98. (g) Ovicillium sp. FCCUFG 99. (h) Pochonia chlamydosporia FCCUFG 100. (i) Purpureocillium lavendulum FCCUFG 101. (j) Sarcopodium sp. FCCUFG 102. (k) Sarocladium hominis FCCUFG 103. (l) Trichoderma helicum FCCUFG 104. (m) Trichoderma sp. FCCUFG 105. (n) Trichoderma sp. FCCUFG 106. (o) Volutella aeria FCCUFG 107.

Figure 5

Mortality rate (means ± standard deviation) of newly hatched Biomphalaria glabrata snails. Negative control group (NC) and exposure to filtrates diluted to 10% (FF10) and 50% (FF50) and undiluted fungal filtrates (FF) during 96 h. The experiment used fungal filtrates produced by isolates representing 13 genera of Hypocreales fungi from a cave in the Brazilian Cerrado. (a) Clonostachys sp. FCCUFG 93. (b) Cylindrocladiella sp. FCCUFG 94. (c) Fusarium sp. FCCUFG 95. (d) Gliocladiopsis elghollii FCCUFG 96. (e) Keithomyces sp. FCCUFG 97. (f) Marquandomyces marquandii FCCUFG 98. (g) Ovicillium sp. FCCUFG 99. (h) Pochonia chlamydosporia FCCUFG 100. (i) Purpureocillium lavendulum FCCUFG 101. (j) Sarcopodium sp. FCCUFG 102. (k) Sarocladium hominis FCCUFG 103. (l) Trichoderma helicum FCCUFG 104. (m) Trichoderma sp. FCCUFG 105. (n) Trichoderma sp. FCCUFG 106. (o) Volutella aeria FCCUFG 107.