Enhancing chlamydospore production in Duddingtonia flagrans on solid substrate: The impact of mannitol and varied cultivation conditions

JUNCO, M.; IGLESIAS, L.E.; ZEGBI, S.; SAGUÉS, M.F.; GUERRERO, I.; BERNAT, G.; FUENTES, M.E.; RIVA, E.; FERNÁNDEZ, A.S.; SAUMELL, C.A.

EXPERIMENTAL PARASITOLOGY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Año: 2024

0014-4894

Duddingtonia flagrans is a nematophagous fungus which has shown promising results as a 18 non-chemical parasitic control tool. The fungus disrupts the parasite´s life cycle by trapping 19 larvae in the environment through the networks generated from chlamydospores, thus 20 preventing the reinfection of animals. One barrier to the development of a commercial 21 product using this tool is the need to increase chlamydospore production in the laboratory for 22 its administration to livestock. The purpose of this study was to evaluate the addition of 23 mannitol to an enriched culture medium and the effect of adverse cultivation conditions on 24 chlamydospore production. D. flagrans was cultivated on Petri dishes with corn agar for 4 25 weeks at 27°C and 70% relative humidity (RH). Four groups were then formed, all with 26 Sabouraud agar as a base, to which different growth inducers were added: GSA (glucose 27 Sabouraud agar), GSA-MI (glucose Sabouraud agar + meso inositol), GSA-E (enriched 28 glucose Sabouraud agar), and AE-M (enriched agar + mannitol). After 4 weeks, 29 chlamydospores were recovered by washing the surface of each plate with distilled water and 30 then quantified. The medium that yielded the highest amount of chlamydospores was 31 subjected to different cultivation conditions: NC (normal conditions): 70% RH and 27°C, 32 AC (adverse conditions) 1: 20% RH and 40°C, CA2: 60% RH and 27°C, and CA3: 55% RH and 24°C. It was determined that mannitol increases chlamydospore production (65x106 33 Journal Pre-proof 34 chlamydospores/plate), and when reducing humidity by 10% under cultivation conditions it 35 resulted in an approximately 10% increase in chlamydospore production compared to the 36 control group. These results suggest that the addition of polyols, as well as its cultivation 37 under certain environmental conditions, can improve chlamydospore production on a 38 laboratory scale.