Plant and Molecular Biology
Permanent URI for this collectionhttp://repository.kln.ac.lk/handle/123456789/22641
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Item Suppression and management of Meloidogyne incognita in soil using Trichoderma harzianum NFCF160 and Trichoderma virens Isf-77(Malaysian Journal of Microbiology, 2022) Rajakaruna, N.; Undugoda, L.; Kannangara, S.; Abeywickrama, K.Aims: Meloidogyne incognita adversely affects numerous crop plants worldwide. Therefore, the modern world has been moving towards biocontrol methods to prevent nematode attacks. This study was aimed to (i) investigate the potential use of Trichoderma harzianum NFCF160 and T. virens Isf-77 in managing M. incognita in soil and (ii) identify trapping mechanisms employed by both Trichoderma strains to suppress M. incognita. Methodology and results: Three weeks old, Basella alba L. plants were subjected to five different treatments. The above and below ground growth parameters and the galling indices of these plants were measured every four weeks for three sampling times. Trapping mechanisms employed by Trichoderma strains were examined following plate assays. Plants treated with T. harzianum NFCF160 and T. virens Isf-77 had significantly higher values for the total number of leaves (34 ± 2.84) and (27 ± 2.61), fresh weight of the shoot (81 ± 9.51 g) and (91 ± 9.70 g), dry weight of the shoot (71 ± 5.24 g) and (62 ± 5.81 g), respectively eight weeks after inoculation of M. incognita. Significantly low galling indices (2 and 2) were recorded in B. alba treated with Trichoderma strains. Both Trichoderma strains exhibited various nematode-trapping mechanisms, such as non-constricting rings and adhesive spores. Conclusion, significance and impact of study: This investigation highlighted the potential of both Trichoderma strains as biocontrol agents to control M. incognita effect in sustainable agriculture.Item Morphological and molecular identification of fungi for their association with postharvest fruit rots in some selected citrus species(2022) Jayasekara, A.; Daranagama, A.; Kodituwakku, T.D.; Abeywickrama, K.Purpose: The availability of fresh Citrus fruits is limited by their susceptibility to invasion by microbial pathogens which leads to cause serious postharvest losses. The present study was carried out to isolate and morphologically identify postharvest fungal associations from selected Citrus fruit species (C. sinensis, C. limon, C. crenatifolia and C. medica) and to confirm their identity by molecular characterization. Research method: Postharvest fungal associations of selected Citrus fruit species were isolated, and identification was done based on morphological characteristics. Confirmation of fungal associations was done through phylogenetic analysis of newly generated ITS sequencing data. Further, frequency of occurrence of each fungal isolate was calculated in three different districts in Sri Lanka. Findings: From the morphological and molecular identification, Collectrichum fructicola, Collectrichum gloeosporioides, Lasiodiplodia theobromae, Aspergillus niger and Pestalotiopsis sp. were recorded from C. sinensis. Neofusicoccum parvum, Collectrichum gigasporium and Aspergillus clavatus were isolated from C. crenatifolia. Further, Lasiodiplodia theobromae and L. pseudotheobromae were the only fungal association isolated from C. limon and C. medica fruit species, respectively. It is worthwhile noting that this is the first report of association of the C. gigasporium and Pestalotiopsis sp. from Citrus fruits in Sri Lanka. Research limitations: Since this research was mainly focused on the isolation and identification of the potential fungal associations, pathogenicity evaluation could not be carried out. Originality/Value: Findings of potential disease causative agents in citrus will be valuable for agriculture sector, to adopt and practice effective strategies to minimize postharvest losses of citrus fruits.Item Dip treatment of Aloe vera gel and Aloe vera in combination with cinnamon essential oils on stem-end rot of mango cv. ‘Karthakolomban’(2022) Karunarathna, N. S. N.; Abeywickrama, K.; Kodituwakku, T. D.This study was conducted to investigate the applicability of Aloe vera gel alone and mixed with cinnamon leaf and bark oil in controlling stem-end rot (SER) and extending the shelf life of mango cv. ‘Karthakolomban’. Mangoes were subjected to dip treatments of Aloe vera gel and Aloe vera gel in combination with cinnamon bark oil (2.0 μL/mL) and cinnamon leaf oil (2.0 μL/mL) and their pathological, physicochemical, sensory properties, and percentage shriveling were evaluated after a 10 d storage period at 12-14℃. Dip treatment of Aloe vera gel + cinnamon oils and Aloe vera gel reduced SER by 3.0 - 6.0%. Physicochemical and sensory properties did not show drastic alterations among all treatments and controls. Mangoes subjected to Aloe vera gel + cinnamon oil treatments demonstrated 0% shriveling. Uncoated fruits showed the highest shriveling. The findings highlight that Aloe vera gel may have a better prospect in the preservation and quality maintenance of mango in combination with cinnamon oils.