ARTICLE | doi:10.20944/preprints202208.0185.v1
Subject: Life Sciences, Other Keywords: fungal systematics; Talaromyces santanderensis; cadmium; cacao rhizosphere; mycoremediation
Online: 10 August 2022 (03:29:20 CEST)
Inorganic pollutants in Colombian cocoa (Theobroma cacao L.) agrosystems cause problems in the production, quality, and exportation of this raw material. There has been an increased interest in bioprospecting studies of different fungal species focused on the biosorption of heavy metals. Furthermore, fungi constitute a valuable, profitable, ecological, and efficient natural soil resource that could be considered in the integrated management of cadmium mitigation. In this study, we report a new species of Talaromyces, isolated from cocoa soil from San Vicente de Chucurí-Colombia. The characterization of the culture was performed on six different standardized media and was distinguished by characteristic colony morphology: biverticillate and monoverticillate penicilli, acerose phialides, and slightly globose smooth-walled conidia. Culture was featured by bright yellow mycelium in young culture on CYA and CYAS medium. Colonies grew faster on Malt and Oat agar, attaining 36 and 32 mm diameter after seven days at 20 ºC. High acid production on CREA medium at 20-30 ºC was observed. Phylogenetic analysis was based on the ITS region and the RPB2, Calmodulin (CaM) and β-Tubulin genes that indicate that it is new to science and is named Talaromyces santanderensis sp. nov. This new species belongs to the Talaromyces section and is closely related to T. lentulus and related to T. soli, T. tumuli and T. pratensis (inside the T. pinophilus species complex) in the inferred phylogeny. Mycelia growth of the fungal strains was subjected to a range of 0-400 ppm Cd and incorporated into malt extract agar (MEA) in triplicates. Fungal radial growth was recorded every three days over a 13-days incubation period and In vitro cadmium tolerance tests showed a high tolerance index = 0,81 when the mycelium was exposed to 300 ppm of Cd. Results suggest T. santanderensis showed tolerance to Cd concentrations that exceed the permissible limits for contaminated soils, and it is promising for its use in bioremediation strategies to eliminate Cd from highly contaminated agricultural soils.