Talaromyces Flavus
1. Classification
a. Higher order taxa
Eukaryota; Ascomycota; Eurotiomycetes; Eurotiales; Trichocomaceae
b. Species
Talaromyces flavus
2. Description and significance
Talaromyces flavus is a fungus well-known for its role in controlling plant pathogens such as Verticillium dahliae through root colonization and the production of antifungal compounds, while also promoting growth, in crops like cotton and potatoes [2][3][4]. This filamentous fungus, belonging to the phylum Ascomycota, commonly inhabits soil and marine sediments [5], where it plays a significant role in nutrient cycling by decomposing organic matter and weathering silicate and serpentine group minerals, releasing magnesium and iron through acid production and physical disruption of the environment via hyphal turgor pressure that mechanically breaks down mineral surfaces [6]. Additionally, T. flavus produces bioactive metabolites with antimicrobial and anticancer properties, including tetradecanoic acid, which has antiproliferative and antioxidant effects; and chalcone derivatives, known for tumor suppression and anti-angiogenesis properties in vitro [5]. T. flavus is also a source of Vitamin E, molecules with activity against bacterial pathogens, and α-D-galactosidase, which may be helpful in prebiotics [7]. T. flavus interacts with the roots of farm plants such as cotton, potato, and eggplant to enhance soil nutrient uptake, potentially reducing crop dependence on chemical fertilizers [2, 8] and demonstrates potential for bioremediation through the degradation of the herbicide nicosulfuron [9]. The current understanding of the genetic makeup and molecular mechanisms of T. flavus, underlying herbicide degradation, is limited [9][10] and there is ongoing debate about the optimal growth medium and conditions required to maximize its effectiveness against plant pathogens such as Verticillium dahliae [3]. It remains unclear whether the benefits of T. flavus in controlled settings translate effectively to agricultural fields [11]
3. Genome structure
The Talaromyces flavus genome has not yet been fully sequenced, so information about its total size, coding and non-coding regions, GC content, and a comprehensive protein list is unavailable. However, partial sequences in databases include 301 nucleotide sequences, 299 genomic sequences, and 47 identified proteins spanning many functional protein families [9]. Some of these proteins belong to metabolic enzymes like glucose oxidase [12] and polyketide synthase [13], DNA/RNA processing proteins such as DNA topoisomerase II [14], RNA polymerase subunits [15], and cytoskeletal proteins such as beta-tubulin [16]. Others include mitochondrial respiration proteins such as cytochrome b and transcription regulators like high-mobility group mating type proteins [17]. Partial genome sequencing indicates that the T. flavus genome encodes β-N-acetylhexosaminidase, a type of chitinase enzyme commonly found in fungi that catalyzes the hydrolysis and synthesis of components in the metabolism of chitin [18]. Its transglycosylation activity facilitates the remodeling and degradation of chitin, which is essential for fungal growth and cell maintenance [19].
Related Talaromyces species, such as Talaromyces sp. DC2, have genomes with approximately 35-40 million base pairs and 45-47% GC content [20]. Talaromyces sp. DC2 contains around 11,000 total genes, many encoding a wide range of carbohydrate-active enzymes targeting plant cell wall components, including 149 genes for cellulose degradation, 227 for hemicellulose, and 153 for pectin [21]. It also harbors 20 biosynthetic gene clusters producing secondary metabolites such as swainsonine and asperterpenoid A, compounds with antimicrobial and anticancer properties [21]. Additionally, DC2 encodes an aromatic L-amino acid decarboxylase gene involved in tryptophan decarboxylation, relevant for indole alkaloid biosynthesis [21]. T. flavus may possess similar capabilities for environmental degradation and bioactive compound production, consistent with reported enzymatic functions such as those performed by β-N-acetylhexosaminidase.
4. Cell structure
Talaromyces flavus is a fast-growing, filamentous fungus that forms bright yellow to orange colonies, with a red pigment that can diffuse into the agar it is plated on [20]. This pigment synthesis depends on the strain. Some, including the T. flavus strains CBS 261.55 and CBS 226.72 produce abundant red pigment, whereas others such as the T. flavus strains CBS 19472, CBS 195.72, and CBS 352.72 produce little to no red pigment. Its hyphae, which are clear to yellow in color and about 1-4µm wide, aggregate into a mycelium [20]. The cell wall of T. flavus is predominantly composed of chitin and β-glucans [22]. It also contains complex water-soluble galactofuranan polysaccharides composed of galactose, mannose, and glucose [22]. These polysaccharides, together with chitin and β-glucans, contribute to the cell’s structural integrity and serve as chemotaxonomic markers that distinguish T. flavus from related fungi.
The reproductive cycle of T. flavus includes sexual spore formation. In its sexual stage, Talaromyces flavus forms yellow, spherical ascomata (fruiting bodies) measuring 200-700µm in diameter [20]. These ascomata contain sacs called asci, each of which holds eight reproductive ascospores [20]. The ascospores are thick-walled, oval, and covered in fine spines [20]. The asci are produced in chains and are surrounded by a network of hyphae that protect the developing spores [20]. In its asexual stage, T. flavus produces upright conidiophores, stalk-like structures that bear small, flask-shaped cells called phialides. Each phialide produces several conidia, the asexual spores, which appear brownish green, oval to round, and 2.2-3.5 x 2.0-2.5µm in length and width [20]. These microscopic characteristics, such as spore size and morphology, are diagnostic for the species.
5. Metabolic processes
Talaromyces flavus, a chemoorganoheterotroph, has demonstrated the ability to degrade herbicides such as nicosulfuron. While the precise enzymatic mechanisms for nicosulfuron degradation remain unknown, identification of key intermediate metabolites such as 2-aminosulfonyl-N, N-dimethylnicotinamide and 2-amino-4,6-dimethoxypyrimidine suggest that T. flavus initiates degradation through cleavage of the sulfonylurea bridge at the C-N and C-S bonds [9]. These intermediates were detected by liquid chromatography–mass spectrometry (LC-MS) during fermentation by T. flavus, and combined with the disappearance of the nicosulfuron parent compound, support a biochemical pathway that breaks the sulfonylurea linkage [9].
T. flavus also secretes extracellular enzymes, including an α-D-galactosidase capable of catalyzing transglycosylation reactions involving tertiary alcohols, such as tert-butyl alcohol [21]. α-D-galactosidase shows broad acceptor specificity and high transglycosylation yields, ranging from 6-34% [7]. This is the first documented instance of enzyme-catalysed α-galactosylation of a sterically hindered alcohol [7]. The ability of the T. flavus α-D-galactosidase to transfer α-galactosyl residues onto such hydrolase-resistant alcohols is unique [7].
T. flavus can also extract inorganic nutrients such as antigorite and lizardite particles from mineral surfaces. One mechanism is mineral weathering, which involves both biomechanical and biochemical forces. The fungus exerts turgor pressure at its hyphal tips (~10-20 μN/μm²), facilitating surface alterations and mineral breakdown [6]. Additionally, the excretion of oxalic acid enhances mineral dissolution [6], further promoting nutrient acquisition.
T. flavus also shows antibacterial activity against bacterial pathogens. This has been seen in marine sediment samples where T. flavus has been isolated and found to produce bioactive compounds for biomedical applications [5]. T. flavus is most active against human pathogens, partly due to antimicrobial properties of secondary metabolites actofunicone, deoxy-funicone, and vermistatin specifically against C. albicans activity [5]. Vitamin E compounds present in T. flavus also exhibit anti-cancer properties, in combination with other chemotherapeutic agents, by blocking enzyme Akt, which is essential for cancer survival. T. flavus also suppresses growth of cancer cells through its use of HEp2 cells [5]. This suggests that further research may support anti-cancer uses of T. flavus.
6. Ecology
Talaromyces flavus inhabits a wide range of environments, including soil, marine sediments, and agricultural fields [8][5]. It grows best in warm conditions and at a neutral to slightly acidic pH (~6.1), which supports optimal biodegradation activity [23][9]. Ecologically, it plays a vital role in soil nutrient cycling by decomposing organic matter and promoting mineral weathering, particularly extracting iron from silicate minerals through its use of hyphal sensing for nutrient foraging [6]. The fungus colonizes plant root zones, where it competitively inhibits pathogenic fungi and may stimulate plant defense responses [2][8]. Talaromyces flavus strain LZM1 offers multiple benefits beyond agriculture. It colonizes the roots of crops such as cotton, potato, tomato, and eggplant, producing antifungal compounds that help control the fungus Verticillium dahliae [2]. Additionally, it promotes growth and biomass in cotton and potato [8]. Under laboratory conditions, strain LZM1 has also demonstrated effective degradation of sulfonylurea herbicides, including tribenuron methyl and chlorsulfuron [9]. T. flavus also shows promise as a natural growth promoter that could reduce agricultural reliance on pesticides and chemical fertilizers [8]. Its spores have been shown to protect early potato tubers and eggplant seeds against pathogens like fungi in the genus Verticillium [2]. Further, adding T. flavus as a seed coating allows colonization among the roots of the eggplant and potato plants.
Another critical role of Talaromyces flavus is its behavior in root-associated microbial communities. T. flavus acts as a natural competitor against plant pathogens, limiting the growth of pathogenic fungi such as Verticillium dahliae by monopolizing nutrients, growth sites, and carbon sources [2][8]. In addition to resource competition, T. flavus produces hydrolytic enzymes such as chitases and glucanases that break down fungal cell wall components, further reducing the ability of other fungi to survive in the same environment [2]. These interactions impact not only pathogen levels but also soil microbial balance and plant development. By becoming established in the root zone, T. flavus improves plant growth by reducing pathogen stress and creating more favorable conditions for nutrient uptake [8]. Greenhouse studies with strains like TF-Co-M-23 in cotton and TF-Po-V-50 in potato have shown that plants treated with T. flavus exhibit greater biomass compared to untreated plants, demonstrating that its ecological impact extends beyond pathogen suppression [8].
7. Pathology
Talaromyces flavus is a nonpathogenic fungus with no known harmful effects on humans or animals. However, T. flavus may be a source of natural anti-cancer compounds [5]. Its production of bioactive metabolites such as vitamin E, tetradecanoic acid, and chalcone have the potential to block key enzymes like Akt, which are essential for cancer cell survival (REF). Furthermore, T. flavus GC-MS testing revealed compounds, such as Chalcone, that effectively suppress tumor growth, invasion, and angiogenesis in vitro and in vivo by inducing apoptosis in human cancer cells through the ROS/MAPK signaling pathway [5].
Talaromyces flavus is widely recognized as an effective biocontrol agent against several plant pathogens, particularly Verticillium dahliae, the cause of Verticillium wilt in crops like cotton, tomato, eggplant, and potato [2][8]. When applied as a seed coating, T. flavus colonizes plant roots, where it competes with pathogenic fungi and produces antifungal compounds and hydrolytic enzymes such as chitases and glucanases, which degrade the pathogen’s cell wall [2]. These interactions significantly reduce the growth and survival of V. dahliae in soil, thereby reducing the risk of infections in subsequent growing seasons. Beyond pathogen suppression, Talaromyces flavus can enhance plant growth. Specific strains of T. flavus, including TF-Co-M-23 for cotton and TF-Po-V-50 for potato, have been shown to enhance plant growth under controlled greenhouse conditions, with growth increases of up to 3.75-fold relative to untreated controls [8].
8. Current Research
Recent research on Talaromyces flavus focuses on its biotechnological applications. Notably, the LZM1 strain can completely degrade 100 mg/L of the herbicide nicosulfuron within 5 days under optimal conditions (pH 6.1, 29°C), demonstrating significant potential for soil detoxification [9]. Marine-derived T. flavus strain SP5 produces bioactive metabolites such as actofunicone, deoxy-funicone, vermistatin, chalcone, and thiophene, which exhibit antimicrobial activity against pathogens such as Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae [5]. Vitamin E compounds detected in this strain also demonstrate potential cytotoxic effects against cancer cell lines at low concentrations, outperforming related fungi Trichoderma gamsii SP4 and Aspergillus oryzae SP6 [5]. Vitamin E acts as an antioxidant and immune-supporting molecule with anti-carcinogenic effects by blocking the activation of Akt, an enzyme essential for cancer cell survival, leading to suppression of HEp2 cancer cell growth [5]. Additional analysis of T. flavus crude extracts revealed bioactive metabolites such as tetradecanoic acid and 2-amino-1,3,4-trihydroxy-8-octadecene, which function as antiproliferative and antioxidant agents and help limit tumor growth through the ROS/MAPK signaling pathway [5]. T. flavus also produces complex sugar compounds through its α-D-galactosidase enzyme, which catalyzes α-galactosylation of sterically hindered tertiary alcohols. This characteristic of T. flavus has been studied in the interest of prebiotic production among other biotechnological applications [7].
Other studies investigate methods to enhance T. flavus growth in crops to strengthen its biocontrol effectiveness and improve soil fertility. T. flavus detects, through bias growth, towards mineral compounds such as antigorite and lizardite and decomposes to enhance plant nutrient uptake [8][23][6]. T. flavus shows significantly faster hyphal growth towards the serpentine minerals antigorite and lizardite compared to quartz and increases its iron content in hyphae up to 8.3 times higher when grown on lizardite [6].
Recent studies also highlight the role of T. flavus in wastewater treatment, where the inoculation of its spores into sludge resulted in the degradation of polysaccharide-rich extracellular polymeric substances (EPS), which decreased the dewaterability of sludge. Breaking down EPS, as well as the enlargement of sludge (pellet formation), contributed to an observed increase in water removal [11]. However, several challenges remain, including mapping the process of EPS degradation, optimizing large-scale cultivation conditions, and assessing its performance in field soils [23][7][5][9][8][6][11].
References
[1] NCBI. (2020) Taxonomy Browser (Talaromyces Flavus). National Center for Biotechnology Information. U.S. National Library of Medicine.
[2] Nagtzaam, M. P. M., & Bollen, G. J. (1997). Colonization of roots of eggplant and potato by Talaromyces flavus from coated seed. Soil Biology and Biochemistry. Volume 29, Issues 9–10, Pages 1499-1507. https://doi.org/10.1016/S0038-0717(97)00015-1.
[3] Engelkes, C. A., Nuclo, R. L., & Fravel, D. R. (1997). Effect of carbon, nitrogen, and C:N ratio on growth, sporulation, and biocontrol efficacy of Talaromyces flavus. Phytopathology, Volume 87, Issue 5, Pages 500–505.
[4] Ayer, W. A., & Racok, J. S. (1990). The metabolites of Talaromyces flavus: Part 1. Metabolites of the organic extracts. Canadian Journal of Chemistry, Volume 68, Issue 11, Pages 2085–2094. https://doi.org/10.1139/v90-318
[5] Bibin G. Anand, C. K. Navin Thomas, S. Prakash. (2016). In Vitro Cytotoxicity and Antimicrobial Activity of Talaromyces Flavus SP5 Inhabited in the Marine Sediment of Southern Coast of India. Chinese Journal of Natural Medicines/Zhongguo Tianran Yaowu/Chinese Journal of Natural Medicines. Volume 14, Issue 12, Pages 913–921. https://doi.org/10.1016/s1875-5364(17)30016-x [6] Li, Z., Liu, L., Lu, X., Zhao, L., Ji, J., & Chen, J. (2021). Mineral foraging and etching by the fungus Talaromyces flavus to obtain structurally bound iron. Chemical Geology, 586, Article 120592. https://doi.org/10.1016/j.chemgeo.2021.120592
[7] Simerska, P., Kuzma, M., Monti, D., Riva, S., Mackova, M., & Karen, V. (2006) Unique transglycosylation potential of extracellular α-d-galactosidase from Talaromyces flavus. Science Direct ; Journal of Molecular Catalysis B: Enzymatic. Volume 39, Issues 1-4. https://doi-org.ezproxy.bu.edu/10.1016/j.molcatb.2006.01.006
[8] Naraghi, L., Heydari, A., Rezaee, S. et al. (2012) Biocontrol Agent Talaromyces flavus Stimulates the Growth of Cotton and Potato. J Plant Growth Regul. Volume 31, Pages 471–477. https://doi.org/10.1007/s00344-011-9256-2
[9] Song, J., Tu, J., Shia, Y., Wu, W., Wang, H., Ruan, Z., Shi, Y., & Yan, Y. (2013). Biodegradation of Nicosulfuron by a Talaromyces Flavus LZM1. Science Direct. https://doi-org.ezproxy.bu.edu/10.1016/j.biortech.2013.02.086
[10] NCBI. (2025) Talaromyces Flavus. National Center for Biotechnology Information. U.S. National Library of Medicine.
[11] Liu, H., Shi, J., Xu, X., Zhan, X., Fu, B., & Li, Y. (2017). Enhancement of sludge dewaterability with filamentous fungi Talaromyces flavus S1 by depletion of extracellular polymeric substances or mycelium entrapment. Bioresource Technology. Volume 245, Pages 977–983. https://doi.org/10.1016/j.biortech.2017.08.185
[12] NCBI. (2001) Glucose oxidase [Talaromyces flavus]. National Center for Biotechnology Information. U.S. National Library of Medicine.
[13] NCBI. (2016) Polyketide Synthase, Partial [Talaromyces flavus]. National Center for Biotechnology Information. U.S. National Library of Medicine.
[14] NCBI. (2024) DNA topoisomerase II, partial [Talaromyces flavus]. National Center for Biotechnology Information. U.S. National Library of Medicine.
[15] NCBI. (2022) RNA polymerase II largest subunit, partial [Talaromyces flavus]. National Center for Biotechnology Information. U.S. National Library of Medicine.
[16] NCBI. (2016) Beta-tubulin, Partial [Talaromyces flavus]. National Center for Biotechnology Information. U.S. National Library of Medicine.
[17] NCBI. (2016) High-Mobility Group Mating-Type Protein MAT1-2-1, partial [Talaromyces flavus]. National Center for Biotechnology Information. U.S. National Library of Medicine.
[18] NCBI. (2012) Talaromyces flavus strain CCF2686 beta-N-acetylhexosaminidase gene, complete cds. National Center for Biotechnology Information. U.S. National Library of Medicine.
[19] Kapešová, J., Petrásková, L., Kulik, N., Straková, Z., Bojarová, P., Markošová, K., Rebroš, M., Křen, V., & Slámová, K. (2020) Transglycosylase activity of glycosynthase type mutants of a fungal GH20 β-N-acetylhexosaminidase. International Journal of Biological Macromolecules. Volume 161, Pages 1206–1215. https://doi.org/10.1016/j.ijbiomac.2020.05.273
[20] Stolk, A. C., & Samson, R. A. (1972) The genus Talaromyces: Studies on Talaromyces and related genera II.Studies in Mycology No. 2.
[21] Quan ND, Nguyen NL, Giang TTH, Ngan NTT, Hien NT, Tung NV, Trang NHT, Lien NTK, Nguyen HH. (2024) Genome Characteristics of the Endophytic Fungus Talaromyces sp. DC2 Isolated from Catharanthus roseus (L.) G. Don. J Fungi (Basel). doi: 10.3390/jof10050352
[22] Leal, J. A., Gómez-Miranda, B., Prieto, A., Domenech, J., Ahrazem, O., & Bernabé, M. (1997) Possible chemotypes from cell wall polysaccharides as an aid in the systematics of Penicillium and its teleomorphic states Eupenicillium and Talaromyces. Mycological Research, Volume 101, Issue 10, Pages 1259–1264. https://doi.org/10.1017/S0953756297004012
[23] Naraghi, L., Naeimi, S., Marzban, R., Heydari, A., & Razavi, M. (2020) A study on the development of Talaromyces flavus formulations by a fermenter and some of their biological properties. The Journal of Research on the Lepidoptera.
Edited by Esha Bhutani, Mina Breen, Shanique Crossdale, Meg McLaughlin, students of Jennifer Bhatnagar for [http://www.bu.edu/academics/cas/courses/cas-bi-311/ BI 311 General Microbiology, 2025, Boston University.
