Clonostachys rosea f. rosea
1. Higher order taxa
Domain: Eukaryota Kingdom: Fungi Phylum: Ascomycota; Class: Saccharomyceta; Order: Hypocreales; Family: Bionectriaceae; Genus: Clonostachys (Schoch, 2020)
2. Description and significance
Clonostachys rosea f. rosea, also known as Gliocladium roseum, is a species of fungus in the Bionectriaceae family that is widespread around the world (Seifert, 2008). It is abundant in environments with high organic matter. It can be identified by blister-like swellings on the walls of the aerial hyphae, which are long branching filaments (Jones et al., 1992). Past research indicated that Gliocladium roseum is mycoparasitic and attacks other fungi like Botrytis cinerea, a pathogenic fungus causing gray mold on many crop plants (Sutton et al., 1997), as well as leafhopper pest species (Toledo et al., 2006). G. roseum is a degrader of bioplastic (Urbanek et al., 2017) and also has potential in medicine, as it functions as a triglyceride synthesis enzyme inhibitor (Tomoda et al., 1999). Current research focuses on G. roseum’s ability to produce compounds associated with diesel fuel (forms “myco-diesel”) ( Strobel et al., 2008). Questions remain on how to best utilize this fungus for mass biodegradation of bioplastics, how to effectively apply the fungus to crops to prevent damage from pests and other fungi, and medications involving G. roseum as an antihyperlipidemic agent for humans (Tomoda et al., 1999).
3. Genome structure
The estimated size of G. roseum’s genome is 58.3 megabases (Mb) and includes 14,628 predicted genes. Compared to other fungi in the Hypocreales order, G. roseum exhibits a higher abundance of genes coding for ATP-binding cassette (ABC) transporters, polyketide synthases, cytochrome P450 monooxygenases, pectin lyases, glucose-methanol-choline oxidoreductases and lytic polysaccharide monooxygenases (Karlsson et al., 2015). G. roseum also has a low number of chitinases (Karlsson et al., 2015). G. roseum’s 28S DNA sequence also differed from those of other Gliocladium species. (Sun et al., 2020).
G. roseum strains ACM941 and 88-710 both exhibit significant genetic similarity (Demissie et al., 2021). G. roseum strain 88-710 was found to have a genome that is 55.5 Mb and includes 17,188 predicted genes. The genome size of G. roseum strain ACM941 was calculated to be 56.9 Mb and carries 17,585 putative genes (Demissie et al., 2021). The two strains share >96% similarity in their encoded genome. Strain-specific traits are most likely due to the changeable 4% of the encoded genome or varying regulation of expressing shared genes, or both factors (Demissie et al., 2021).
4. Cell structure
The cell structure of G. roseum is made up of Acrostalagmus-like conidiophores, which resemble small branches. Penicillate heads are the brush-like tips of certain branches where the spores develop and are kept (Jones et al., 1992). Mucus-coated balls (mucoid balls) and thread-like structures (rope-like formations) can be found at the end of these branches (called terminals). Smaller spores (conidia) are found within these balls and thread structures (Jones et al., 1992). The appearance of blister-like swellings on the walls of the aerial hyphae (long branching filaments) and conidiophores is a distinctive characteristic of these structures (Jones et al., 1992).
Diamorphy is found in G. roseum where it exists in two forms: In Form 1, Gliocladium roseum has early-formed structures called conidiophores that resemble branches. These branches have long, spreading parts at the ends (Schroers et al., 1999). On these spreading parts, small, round structures, referred to as conidia, attach in small masses. In Form 2, Gliocladium roseum forms branches with the phialides, which are smaller, pressed-down parts at the ends (Schroers et al., 1999). On these phialides, there are rows of tiny structures that overlap. These structures are also conidiophores, but in this form, they have smaller compressed parts and overlapping columns (Schroers et al., 1999).
5. Metabolic processes
G. roseum is an endophytic fungus that functions well under microaerophilic conditions (Strobel et al., 2008). It produces volatile hydrocarbon metabolites, including acetic acid esters with straight chain structures and decyl alcohols. Moreover, it has been shown to produce cellulolytic enzymes enabling it to break down cellulose (Salem & Abdel-Rahman, 2015). This ability enables it to feed on plant material. G. roseum also digests material (like amino acids) in soil as a saprophyte (Mohammed et al., 2022). It has been found to metabolize tryptophan into tryptamine (TRA) and indole-3-acetaldehyde (IAAId), which are used by G. roseum to produce indole-3-acetic acid (IAA) through the tryptamine (TAM) pathway 2. IAA is one of the major pathways in tryptophan-dependent IAA biosynthesis 2 (Han et al., 2022). It also produces antifungal metabolites which induce plant defense (Barnett & Lilly, 1962).
G. roseum also secretes a wide array of enzymes, including cutinase, lipase, proteases, carboxylesterases, and esterases, making it a potent plastic degrader. These enzymes facilitate the degradation of plastics through oxidation and hydrolysis, breaking down high molecular weight polymers into smaller, more transportable monomers (Srikanth et al., 2022).
6. Ecology
G. roseum is a versatile fungus that is most commonly found in environments rich in decaying organic matter (e.g., compost heaps and plant debris) and organic materials like forests, grasslands, freshwater ponds, and coastal areas (Sutton et al., 1997). G. roseum is also found living in areas with a higher pH (Sutton et al., 1997). G. roseum uses chlamydospores and conidia to respond to radical changes in their environment. Chlamydospores form when the fungus is subjected to harsh environmental conditions such as low pH and low temperature (Sun et al., 2020). Chlamydospores are more resistant to unfavorable environments like deserts and subarctic regions (Sun et al., 2020). G. roseum acts as a mycoparasite of several fungal taxa, while being harmless to plants and animals (Barnett & Lilly, 1962).
G. roseum is pathogenic to the fungus Botrytis cinerea (fungi which produces gray mold on strawberries, raspberries, tomatoes, cucumber, etc.) and was found to suppress its growth and spore production by 98%. The fungus attacks B. cinerea by coiling its hyphae around the condida of B. cinerea and penetrating it (Sutton et al., 1997) B. cinerea produces hydrogen peroxides due to G. roseum’s attack, but G. roseum’s ABC-transporter gene 29 provides oxidative stress tolerance (Dubey et al., 2015). G. roseum also kills colonies of Ceratocystis fagacaerum in nature, but only when it is in direct contact with C. fagacaerum which indicates that the antibiotic released by G. roseum is not highly diffusible (Barnett & Lilly, 1962).
G. roseum is a naturally occurring pathogen of the leafhoppers Oncometopia tucumana and Sonesimia grossa, which are vectors for plant pathogens in crops such as citrus and coffee (Toledo et al., 2006). C. rosea also prevents Fusarium graminearum from accumulating mycotoxin in the oat grain and thus inhibiting oat infections (Alfia Khairullina et al., 2023).
G. roseum acts as a predator of various nematode species that are gastrointestinal parasitic nematodiases (GPN). GPNs affect livestock (ie. sheep) and cause over millions of dollars of damage annually (Rodríguez-Martínez et al., 2018). One nematode that G. roseum attacks is H. contortus, which causes malnutrition, lack of growth, and death of young animals. While G. roseum shows potential as a control agent by attacking H. contortus larvae, it also attacks free-living nematodes that help in nitrogen cycles (Rodríguez-Martínez et al., 2018). The decrease in free-living nematodes due to G. roseum predation is not significant due to nematode’s capability to reproduce themselves quickly (Rodríguez-Martínez et al., 2018).
7. Pathology
Fungi in the family Gliocladium have been considered an opportunistic pathogen of humans and primarily affects immunocompromised individuals, those who have weakened immune systems, and makes them more susceptible to fungal infections (Venkatesh et al., 2017). For instance, a case of ocular infection by Gliocladium species was reported with an individual who had exposed scleral buckles in the eye due to prior surgery. The specific mechanisms by which G. roseum causes infection are not extensively studied due to its limited prevalence as a pathogen (Venkatesh et al., 2017). However, like many opportunistic fungi, it is believed to take advantage of weakened or compromised host defenses to establish infection. While there is limited data available on antifungal resistance specific to G. roseum, some fungi within the Gliocladium genus have shown resistance to common antifungal medications (Venkatesh et al., 2017). This resistance can complicate the treatment of infections and may necessitate the use of more specialized antifungal agents. Overall, G. roseum infections are relatively rare, and the fungus is not typically associated with widespread human pathogenicity. More research on G. roseum is required to determine whether G. roseum is a pathogenic agent (Venkatesh et al., 2017).
8. Industrial Applications
G. roseum is capable of synthesizing various alkanes, alkenes, and alcohols, and several of these compounds are similar to those found in diesel fuel for motor vehicles. These molecules are referred to as mycodiesel carbons (Strobel et al., 2008). Fungi with myco-diesels are easy to grow and show a promising new industry over other oil sources like algae and yeast which have pickier growing conditions (Magdum et al., 2015).
G. roseum can degrade biobased and biodegradable plastics (bioplastics). It has one of the highest capabilities for biodegradation out of various arctic microorganisms and can grow at low temperature (Urbanek et al., 2017). This is possible due to the various enzymes G. roseum produces to help in oxidizing and hydrolyzing bioplastics into smaller molecules (Srikanth et al., 2022).
9. Medical Applications
G. roseum produces molecules that are diacylglycerol acyltransferase (DGAT) inhibitors, such as roselipin. DGAT is an important enzyme in triacylglycerol synthesis in the body (Tomoda et al., 1999). Too much triacylglycerol synthesis leads to chronic health issues like diabetes and atherosclerosis. Roselipin's antimicrobial properties and DGAT inhibition were tested in rat liver microsomes (Tomoda et al., 1999). Scientists are interested in pursuing roselipin studies in larger mammals (Tomoda et al., 1999).
G. roseum also produces silver nanoparticles that show inhibitory activity (antimicrobial activity) against Salmonella typhi and Klebsiella pneumonia, which are two human pathogenic bacteria (Nair et al., 2020). The mechanism of silver nanoparticles involves their ability to latch onto and penetrate the bacterial cell wall, which causes changes in the cell membrane and leads to cell death. The silver nanoparticles also form free radicals that can damage the cell membrane and lead to death (Nair et al., 2020).
10. Current Research
There was a controversy in 2010 where G. roseum was incorrectly identified as the microorganism producing biofuel (Griffin et al., 2010). However, more recent research in 2015 indicates that G. roseum still produces compounds found in diesel fuel (Magdum et al., 2015). Current research focuses on understanding the optimal conditions for myco-diesel production and forming strains that will contribute to mass production of myco-diesel from G. roseum (Strobel, 2014).
Another focus of current research includes how to better utilize G. roseum for medical purposes. Scientists are interested in how to better utilize G. roseum’s roselipin production for human cardiovascular disease prevention since the inhibitor’s effect has only been studied in rats (Tomoda et al., 1999). Recent research also indicates that G. roseum produces various cancer-fighting compounds. One compound of interest is 13-oxo-trans-9,10-epoxy-11(E)-octadecenoic acid. This compound was tested against Merkel cell carcinoma cell lines and showed cytotoxic activity toward the cell dolines, which suggests that G. roseum can possibly aid in Merkel cell carcinoma treatments (Kim et al., 2021).
Researchers are concerned about how to best apply G. roseum onto crops to protect against pathogenic fungi like B. cinerea since poorly understood factors like atmospheric humidity, rain, and other sources of environmental water must be considered. Environmental water is particularly important to G. roseum’s growth and protection of plants (Sutton et al., 1997). Moreover, the application of G. roseum depends on the specific crop in question (e.g., G. roseum is applied differently to strawberry and raspberry plants) (Sutton et al., 1997). In all, scientists are concerned about how to effectively utilize G. roseum for mass production, especially for environmental, industrial, and medical uses.
11. References
Alfia Khairullina, Nikola Mićić, Jørgen, H., Nanna Bjarnholt, Bülow, L., Collinge, D. B., & Jensen, B. (2023). Biocontrol Effect of Clonostachys rosea on Fusarium graminearum Infection and Mycotoxin Detoxification in Oat (Avena sativa). Plants, 12(3), 500–500. https://doi.org/10.3390/plants12030500
Barnett, H. L., & Lilly, V. G. (1962). A Destructive Mycoparasite, Gliocladium Roseum. Mycologia, 54(1), 72. https://doi.org/10.2307/3756600
Demissie, Z. A., Robinson, K. A., & Loewen, M. C. (2021). Draft Genome Resources for Plant-Beneficial Fungi Clonostachys rosea Strains ACM941 and 88-710. Molecular Plant-Microbe Interactions, 34(4), 453–456. https://doi.org/10.1094/mpmi-10-20-0294-a
Dubey, M., Dan Funck Jensen, & Karlsson, M. (2015). The ABC transporter ABCG29 is involved in H2O2 tolerance and biocontrol traits in the fungus Clonostachys rosea. Molecular Genetics and Genomics, 291(2), 677–686. https://doi.org/10.1007/s00438-015-1139-y
Griffin, M. A., Spakowicz, D. J., Gianoulis, T. A., & Strobel, S. A. (2010). Volatile organic compound production by organisms in the genus Ascocoryne and a re-evaluation of myco-diesel production by NRRL 50072. Microbiology, 156(12), 3814–3829. https://doi.org/10.1099/mic.0.041327-0
Han, Z., Hossein Ghanizadeh, Zhang, H., Li, X., Li, T., Wang, Q., Liu, J., & Wang, A. (2022). Clonostachys rosea Promotes Root Growth in Tomato by Secreting Auxin Produced through the Tryptamine Pathway. Journal of Fungi, 8(11), 1166–1166. https://doi.org/10.3390/jof8111166
Jones, David; Vaughan, Derek; and McHardy, William J. (1992) "Scanning Electron Microscopy of a Soil Fungus Gliocladium roseum," Scanning Microscopy, 6(2), 591–596. https://digitalcommons.usu.edu/microscopy/vol6/iss2/23
Karlsson, M., Durling, M. B., Choi, J., Kosawang, C., Lackner, G., Tzelepis, G. D., Nygren, K., Dubey, M. K., Kamou, N., Levasseur, A., Zapparata, A., Wang, J., Amby, D. B., Jensen, B., Sarrocco, S., Panteris, E., Lagopodi, A. L., Pöggeler, S., Vannacci, G., & Collinge, D. B. (2015). Insights on the Evolution of Mycoparasitism from the Genome of Clonostachys rosea. Genome Biology and Evolution, 7(2), 465–480. https://doi.org/10.1093/gbe/evu292
Kim, C.-K., Krumpe, L. R. H., Smith, E., Henrich, C. J., Brownell, I., Wendt, K. L., Cichewicz, R. H., O’Keefe, B. R., & Gustafson, K. R. (2021). Roseabol A, a New Peptaibol from the Fungus Clonostachys rosea. Molecules, 26(12), 3594. https://doi.org/10.3390/molecules26123594
Magdum, S. S., Minde, G. P., Adhyapak, U. S., & V. Kalyanraman. (2015). Competence evaluation of mycodiesel production by oleaginous fungal strains: Mucor circinelloides and Gliocladium roseum. International Journal of Energy and Environment, 6(4), 377–382. https://ssrn.com/abstract=2628540
Mohammed, A. A., Ahmed, F. A., Younus, A. S., Kareem, A. A., & Salman, A. (2022). Molecular identification of two entomopathogenic fungus Clonostachys rosea strains and their efficacy against two aphid species in Iraq. Journal of Genetic Engineering and Biotechnology, 20(1). https://doi.org/10.1186/s43141-022-00347-y
Nair, B., Abraham, D., Dinesh, A., & Swamy, G. E. M. (2020). “MYCO SYNTHESIS OF SILVER NANOPARTICLES USING GLIOCLADIUM ROSEUM (CLONOSTACHYS ROSEA (LINK) SCHROERS, SAMUELS) AND ITS ANTIMICROBIAL EFFICACY AGAINST SELECTED PATHOGENS.” International Journal of Current Pharmaceutical Research, 12(6), 77–84. https://doi.org/10.22159/ijcpr.2020v12i6.40293
Rodríguez-Martínez, R., Mendoza-de-Gives, P., Aguilar-Marcelino, L., López-Arellano, M. E., Gamboa-Angulo, M., Hanako Rosas-Saito, G., Reyes-Estébanez, M., & Guadalupe García-Rubio, V. (2018). In Vitro Lethal Activity of the Nematophagous Fungus Clonostachys rosea (Ascomycota: Hypocreales) against Nematodes of Five Different Taxa. BioMed Research International, 2018, 1–7. https://doi.org/10.1155/2018/3501827
Salem, A. A., & Abdel-Rahman, H. M. (2015). OPTIMIZATION AND CHARACTERIZATION OF CELLULOLYTIC ENZYMES PRODUCED FROM Gliocladium roseum. Journal of Agricultural Chemistry and Biotechnology, 6(11), 473–488. https://doi.org/10.21608/jacb.2015.48469
Schoch, cl. (2020). Taxonomy browser (Clonostachys rosea f. rosea). Www.ncbi.nlm.nih.gov. https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&id=768735&lvl=3&lin=f&keep=1&srchmode=1&unlock
Schroers, H.-J., Samuels, G. J., Seifert, K. A., & Gams, W. (1999). Classification of the Mycoparasite Gliocladium roseum in Clonostachys as C. rosea, Its Relationship to Bionectria ochroleuca, and Notes on Other Gliocladium-like Fungi. Mycologia, 91(2), 365. https://doi.org/10.2307/3761383
Seifert, K. A. (2008). Compendium of Soil Fungi - by K.H. Domsch, W. Gams & T.-H. Anderson,. European Journal of Soil Science, 59(5), 1007–1007. https://doi.org/10.1111/j.1365-2389.2008.01052_1.x
Srikanth, M., Sandeep, T. S. R. S., Sucharitha, K., & Godi, S. (2022). Biodegradation of plastic polymers by fungi: a brief review. Bioresources and Bioprocessing, 9(1). https://doi.org/10.1186/s40643-022-00532-4
Strobel, G. A. (2014). The story of mycodiesel. Current Opinion in Microbiology, 19, 52–58. https://doi.org/10.1016/j.mib.2014.06.003
Strobel, G. A., Knighton, B., Kluck, K., Ren, Y., Livinghouse, T., Griffin, M., Spakowicz, D., & Sears, J. (2008). The production of myco-diesel hydrocarbons and their derivatives by the endophytic fungus Gliocladium roseum (NRRL 50072). Microbiology, 154(11), 3319–3328. https://doi.org/10.1099/mic.0.2008/022186-0
Sun, Z.-B. ., Li, S.-D. ., Ren, Q., Xu, J.-L. ., Lu, X., & Sun, M.-H. . (2020). Biology and applications of Clonostachys rosea. Journal of Applied Microbiology, 129(3), 486–495. https://doi.org/10.1111/jam.14625
Sutton, J. C., Li, D.-W., Peng, G., Yu, H., Zhang, P., & Valdebenito-Sanhueza, R. M. (1997). GLIOCLADIUM ROSEUM A VERSATILE ADVERSARY OF BOTRYTIS CINEREA IN CROPS. Plant Disease, 81(4), 316–328. https://doi.org/10.1094/pdis.1997.81.4.316
Toledo, A., Eduardo Gabriel Virla, Humber, R. A., Susana Liria Paradell, & C.C. López Lastra. (2006). First record of Clonostachys rosea (Ascomycota: Hypocreales) as an entomopathogenic fungus of Oncometopia tucumana and Sonesimia grossa (Hemiptera: Cicadellidae) in Argentina. Journal of Invertebrate Pathology, 92(1), 7–10. https://doi.org/10.1016/j.jip.2005.10.005
Tomoda, H., Ohyama, Y., Abe, T., Tabata, N., Namikoshi, M., Yamaguchi, Y., Masuma, R., & Omura, S. (1999). Roselipins, Inhibitors of Diacylglycerol Acyltransferase, Produced by Gliocladium roseum KF-1040. The Journal of Antibiotics, 52(8), 689–694. https://doi.org/10.7164/antibiotics.52.689
Urbanek, A. K., Rymowicz, W., Strzelecki, M. C., Kociuba, W., Franczak, Ł., & Mirończuk, A. M. (2017). Isolation and characterization of Arctic microorganisms decomposing bioplastics. AMB Express, 7(1). https://doi.org/10.1186/s13568-017-0448-4
Venkatesh, R., Gurav, P., Agarwal, M., Sapra, N., & Dave, P. A. (2017). Ocular infection with Gliocladium species—report of a case. Journal of Ophthalmic Inflammation and Infection, 7(1). https://doi.org/10.1186/s12348-017-0128-1
Edited by WZ, DH, LK, BA, TL - students of Jennifer Bhatnagar for BI311: General Microbiology,2023, Boston University
