Browsing by Author "Daranagama, D. A."

Now showing 1 - 7 of 7

Bioremediation potential of wood-associated fungi in Rajawaka forest reserve, Balangoda
(Faculty of Science, University of Kelaniya Sri Lanka, 2023) Nadungamuwa, D. M. H. S. K.; Kannangara, B. T. S. D. P.; Daranagama, D. A.
Sri Lanka consists of a high diversity of fungal species, especially wood-associated fungi. These fungi play a vital ecological role in wood decomposition and have potential applications in environmental remediation due to their unique enzyme systems. Currently, the accumulation of polycyclic aromatic hydrocarbons (PAHs), mainly from vehicular emissions has become a significant environmental concern. Therefore, the present study aimed to identify the woodassociated macro and micro fungi in the Rajawaka forest reserve which is a lowland secondary forest located in the Balangoda area in the Rathnapura district, and to assess their ability to degrade specific PAHs, including phenanthrene, naphthalene, pyrene, and anthracene. Identification keys followed by morphological characteristics and image-based methods were used to identify the macrofungi. Microfungi were isolated following surface sterilization and culturing on potato dextrose agar (PDA) plates. Most frequently isolated fungal strains were subjected to plate assay to assess the fungal growth in PAHs by using 8 replicates. Control plates were prepared without inoculating fungi for each PAH-incorporated media. Spectrophotometric analysis was done to determine their PAH degradation abilities using 3 replicates. Controls were prepared without inoculating fungi. Obtained data were analyzed using ANOVA and Tukey’s pairwise comparison by using Minitab 17 statistical software. The macrofungi collected from the Rajawaka forest reserve were mainly in the phylum Basidiomycota; Ganoderma sp., Pycnoporus sp., Phellinus sp., Hexagonia sp., Trametes sp., Earliella sp., Schizophyllum sp., Lentinus sp., Calocera sp., Stereum sp., Microporus sp., and Pleurotus sp. Frequently isolated microfungi included Trichoderma sp. 1, Trichoderma sp. 5, Trichoderma sp. 6, Grey sterile sp., Mortierella sp. 2, Brown sporulating sp., Humicola sp., and Aspergillus sp. 1. Mortierella sp. 2 and Grey sterile sp. were significantly effective in degrading phenanthrene (42.51%, and 34.16% respectively) and naphthalene (41.27%, and 33.48% respectively), while Humicola sp. and Grey sterile sp. showed a high degradation capacity for anthracene (33.73%, and 23.72% respectively) and pyrene (30.62%, and 19.32% respectively). All the PAHs studied were efficiently degraded by Grey sterile sp. This investigation serves as a preliminary exploration of the wood-associated macro and microfungal diversity in the Rajawaka forest reserve, and their potential in remediating PAH pollutants. It also opens the avenue for future research in finding environmental solutions for bioremediation of PAH deposition in Sri Lanka.
First comprehensive study on distribution frequency and incidence of seed-borne pathogens from cereal and legume crops in Sri Lanka
(2022) Ganeshalingam, A.; Daranagama, D. A.
Sri Lanka as an agricultural country requires seed health testing to rnanage crop diseases. So tar no comprehensive research has been can'ied out for the proper identi fication olseed mycoflora af ltcting the seed quality in Sri Lanka. The present sfudy strives to address this issue by identifying seed-borne fungal pathogens from stored seeds usirg morpho-molecular characterization. Fungal pathogens were isolated lrom surface-sterilized and non-surface sterilized seeds of .,lrachis hypogeu, Or1':a sativa. Ligra radiata, andl4gna srnensls. PCR arnplilication and DNA sequencing olthe intemaL transcribed spacer (ITS) region was carried out for molecular identit-rcation of pathogens. The genaination qualiry of each seed vanety was calculated by pot experiments. Distnbution tiequencies. percentage of germination, and seedling vigor were calculated and analyzed tbr each seed variery tested. In total eighteen isolates were recovered fi'om the fbur seed varieties. Molecular characterization revealed that the fungal isolates recovered from all the four seed varieties belong to seven senera: ,lspergillus, Bipolaris, Daldiuia, lrlacroplromirn, Orbilia, Rhi:opus, and Tuluroml,ces. Rhi:opus spp. showed the highest distribution frequency (15%). Arachis hv-pogea showed the lowest gennination percentage (20%) and lowest seedling vigor index (585). The seeds ofOry:a rativd shorved no gennination probably due to their high incidence offungal pathoqens (loul out ol seven genera). This study is tl.re tlrst comprehensive sLudy analyzing the seed-borne pathogens ol the lour most commonly consurned Sri Lankan cereal and legume crops. Results reported in this study helps to identi[y and implement optimum storage facilities and control such fungal pathogens in future agricultural practices.
Fungi vs. Fungi in Biocontrol: An Overview of Fungal Antagonists Applied Against Fungal Plant Pathogens
(Frontiers in Cellular and Infection Microbiology, 2020) Thambugala, K. M.; Daranagama, D. A.; Phillips, A. J. L.; Kannangara, S. D.; Promputtha, I.
Plant pathogens cause severe losses or damage to crops worldwide and thereby significantly reduce the quality and quantity of agricultural commodities. World tendencies are shifting towards reducing the usage of chemically synthesized pesticides, while various biocontrol methods, strategies and approaches are being used in plant disease management. Fungal antagonists play a significant role in controlling plant pathogens and diseases and they are used as Biocontrol Agents (BCAs) throughout the world. This review provides a comprehensive list of fungal BCAs used against fungal plant pathogens according to modern taxonomic concepts, and clarifies their phylogenetic relationships because thewrong names are frequently used in the literature of biocontrol. Details of approximately 300 fungal antagonists belonging to 13 classes and 113 genera are listed together with the target pathogens and corresponding plant diseases. Trichoderma is identified as the genus with greatest potential comprising 25 biocontrol agents that have been used against a number of plant fungal diseases. In addition to Trichoderma, nine genera are recognized as significant comprising five or more known antagonistic species, namely, Alternaria, Aspergillus, Candida, Fusarium, Penicillium, Pichia, Pythium, Talaromyces, and Verticillium. A phylogenetic analysis based on partial sequences of the 28S nrRNA gene (LSU) of fungal antagonists was performed to establish their phylogenetic relationships.
Global Challenges in Identifying Plant Pathogenic Fungi: An Overview with Suggestions for the Way Forward
(Chiang Mai Journal of Science, 2023) Dayarathne, M. C.; Thambugala, K. M.; Daranagama, D. A.; Mridha, A. U.; Dissanayake, A. J.; Dissanayake, L. S.; Sajeewa, S. N. Maharachchikumbura; Rathnayake, R. S. S.; Lumyong, Saisamorn; Hongsanan., Sinang
Fungal plant diseases are responsible for major crop and postharvest losses worldwide, with a significant socio-economic impact on many individuals who depend on an agriculture-based economy. This review discusses the major constraints in identifying plant pathogenic fungi (severely destructive on important crops) in sample collection, field, and morphological observations, fungal isolation, obtaining pure cultures, applying Koch’s postulates, DNA barcoding, phylogenetic analyses, and naming fungi (under “One fungus, One name” concept) based on selected case studies. Additionally, available strategies/methods to overcome those limitations up to date are also discussed. Ultimately, we proposed suggestions to minimize those limitations.
Multigene Phylogeny Reveals Endophytic Xylariales Novelties from Dendrobium Species from Southwestern China and Northern Thailand
(Journal of fungi (Basel, Switzerland), 2022) Ma, X.; Chomnunti, P.; Doilom, M.; Daranagama, D. A.; Kang, J.
Xylariales are common endophytes of Dendrobium. However, xylarialean species resolution remains difficult without sequence data and poor sporulation on artificial media and asexual descriptions for only several species and old type material. The surface-sterilized and morph-molecular methods were used for fungal isolation and identification. A total of forty-seven strains were identified as twenty-three species belonging to Apiosporaceae, Hypoxylaceae, Induratiaceae, and Xylariaceae. Five new species-Annulohypoxylon moniliformis, Apiospora dendrobii, Hypoxylon endophyticum, H. officinalis and Nemania dendrobii were discovered. Three tentative new species were speculated in Xylaria. Thirteen known fungal species from Hypoxylon, Nemania, Nigrospora, and Xylaria were also identified. Another two strains were only identified at the genus and family level (Induratia sp., Hypoxylaceae sp.). This study recorded 12 new hosts for xylarialean endophytes. This is the first report of Xylariales species as endophytes from Dendrobium aurantiacum var. denneanum, D. cariniferum, D. harveyanum, D. hercoglossum, D. moniliforme, and D. moschatum. Dendrobium is associated with abundant xylarialean taxa, especially species of Hypoxylon and Xylaria. We recommend the use of oat agar with low concentrations to induce sporulation of Xylaria strains.
Observations on Sri Lankan Hypoxylon: a comprehensive morphological study on H. anthochroum, H. flavoargillaceum, and H. piceum
(Faculty of Science, University of Kelaniya, Sri Lanka., 2021) Palapathwala, P. L. E. S.; Ganeshalingam, A.; Daranagama, D. A.
Most of the Hypoxylon species are saprobic and usually one of the earliest species to colonize the deteriorated wood. The species of Hypoxylon belonging to the family Hypoxylaceae exhibit a large diversity of fungi in tropical countries like Sri Lanka. However, research on the identification and classification of Hypoxylaceous species is scarce in Sri Lanka. The present study was aimed towards the identification of Sri Lankan Hypoxylaceous species and to produce a stable classification for species nomenclature based on a reliable approach using distinguishable morphological characteristics. An assessment of hypoxylaceous fungi was carried out in the Pilikuththuwa lowland wet zone forest area in Sri Lanka and several Hypoxylon species were identified morphologically, using both macroscopic and microscopic characteristics including features of stromata, ascomata, asci, ascospores, the colour of KOH extractable pigments and culture characteristics. Based on the results the identity of H. anthochroum, H. flavoargillaceum, and H. piceum were confirmed by morphology.
Valorization of diaper waste into sustainable production of commercially grown Pleurotus spp. in Sri Lanka
(Faculty of Science, University of Kelaniya Sri Lanka, 2023) Nawarathne, I. Y.; Daranagama, D. A.
Oyster mushrooms (Pleurotus spp.) are commercially grown and consumed for their taste, high nutritional value, and medicinal properties. In Sri Lanka, oyster mushroom cultivation is practiced on a small scale as a self-employment cottage industry. With the scarcity as well as increased cost of conventional substrate materials, the use of an efficient, cost-effective, and sustainable alternative substrate is a key factor in promoting the oyster mushroom industry within the country. Disposable diapers representing about 4% of solid waste, which is the third largest consumer item discarded after a single use, pose a great burden on landfill sites causing adverse impacts on the environment. Therefore, this study aimed to develop a sustainable cultivation protocol using diaper waste to effectively cultivate oyster mushrooms. For this purpose, sterilized diaper cores (1%, 2%, 4%, and 6%) containing liquid waste, were mixed with commercial growth substrate. The treatments were statistically analyzed using One-way ANOVA for their mycelium running rate at 10 days intervals until complete colonization of the substrate blocks and the total yield of mushrooms for a duration of 2 months from the first fruiting date of the four commercially cultivated oyster mushroom species in Sri Lanka; Pleurotus djamor, Pleurotus eous, Pleurotus ostreatus, and Pleurotus cystidiosus in comparison with the control treatment containing 100% commercial growth substrate. According to the statistical analysis, the mycelium spreading rate of all the treatments with diaper core incorporation was comparatively higher than the control in P. ostreatus, P. djamor, and P. eous except for P. cystidiosus, in which 1% diaper core incorporation was reported the lowest mycelium spreading rate. In all four Pleurotus species, 2% and 4% diaper core incorporation led to the fastest running rate and was significantly higher than the control treatments and other treatments. According to statistical analysis, the means of the total yield of treatments and control of the four Pleurotus species were not significantly different. However the highest production yield was obtained from 4% of diaper core incorporation for P. ostreatus (990 g), P. eous, (855 g) and P. cystidiosus (820 g) except for P. djamor (670 g) for which the highest yield was observed at 2 % diaper core incorporation. With the results obtained, we could confirm that the high lignocellulose content, high N, P, and K content as well as the water retention abilities of used diaper cores suggest a potential for mushroom cultivation through lignocellulose enzymatic reactions. Therefore, our study proposed a potential resource management towards the zero-waste concepts, where diaper waste is no longer a debit entry but a valuable resource for today’s circular economy that can be used as a cultivation medium for sustainable mushroom cultivation.