Plant and Molecular Biology

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Author: search.filters.author.Daranagama, D. A.Start date: 2022

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    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.
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    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.
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    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.