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Title of Thesis

Sharfun Nahar
Institute/University/Department Details
University Of Karachi,/ Department Of Botany
Number of Pages
Keywords (Extracted from title, table of contents and abstract of thesis)
metabolites, toxigenic fusarium species, seed-borne, seed-borne mycoflora, artificial infestation, killer yeasts, fusairum spp, secondary metabolites

Twelve seed-borne Fusarium Link. Ex Fr. Species were isolated from 7 different economically important crops and identified as F. anthophilum (A. Braun) Wollenw, F. Chlamydosporum Wollenw. & Reinking, F. equiseti (Corda) Sacc. Sensu Gordon, F. longipes Wollenw. & Reinking sensu Gordon, F. moniliforme Scheldon, F. exysporum Schlecht. Emend. Snyd. & Hans., F. pallidoroseum (Cooke) Sacc., F. proliferatum (Matsushima) Nirenberg, F. scirpi Lambotte & Fautr., F. solani (Mart.) Appel & wollenw. Emend.Snyd. & Hans., F. sporotrichioides Cherb. And F. subglutinans (Wollenw. & Reinking) Nelson, Toussoun & Marasas comb. Nov. Highest occurrence of Fusairum spp. Was enxountered in capsicum, corn, pearlmillet and sunflower seeds. F. anthophilum on corn and pearlmillet; F. chlamydosporum on capsicum and mustard; F. equiseti on sunflower; F. proliferatum and F. subglutinans on linseed and mustard were newly recorded species from Pakistan. Seed transmission studies revealed that F. anthophilum, F. moniliforme, F. oxysporum, F. solani and F. subglutinans that eaused wilting and rotting were systemic pathogens of sunflower. During pathogenicity experiments, Fusarium spp. Produced symptoms of root-, collarstem and seedling rots, damping-off, stunting, wilting, yellowing, tip burn and reduction in growth. Wilting was the most prominent symptom followed by seedling rot. Highest wilting was produced by F. chlamydosporum and F.subglutinans, whereas, highest seedling rot was caused by F. solani and F. sporotrichioides.

In dual culture plate assays between fusairum spp. And killer yeasts, Y21-Bullera pseudoalba appeared as the most successful antagonist as compared to Y16-Pichia anomala and Y20-Sporidiobolus ruineniae. These killer yeast strains promoted vigor of sunflower plants when applied alone in soil. During bio-control experiments by soil amendment method, they significantly reduced infection and colonization of roots by Fusarium spp. As compared to seed treatment.

Prkofiles of secondary metabolites of fusarium spp. Produced consistent chromatographic patterns on TLC in which bostrycoidin, cis-dihydrofusarubin, vomitoxin (deoxynivaleonol), isomarticin, nectriafurone, zearalenone, zearalenol and other derivatives were identified.

Using column chromatography 3 scondary metabolites of F. chlamydosporum, 1 of F. euiseti and 2 of F. pallidoroseum were detected. Secondary metabolites of F. chlamydosporum were identified as Bis(2-methylpropyl)ester of (Diisobutyl phthalate). Cyanidin 3-(xylosylarabinoside) and Lotusin E. Likewise secondary metabolite of F. equiseti was identified as Meliteric acid B and metabolites of F. pallidoroseum were identified as Musacine K and Radulanin A. These secondary metabolites were isolated for the first time from Fusarium spp.

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1662.72 KB
S. No. Chapter Title of the Chapters Page Size (KB)
1 0 Contents
39.48 KB
2 1 Summary I
66.46 KB
3 2 Introdution 1
34.83 KB
4 3 Literature Review 5
195.63 KB
  3.1 Seed-Borne Pathogneic Fusarum Spp. 5
  3.2 Biological Control Of Fusarium Spp. 10
  3.3 Mycotoxins/Secondary Metabgolites Of Fusarium Spp. 13
5 4 Materials And Methods 23
142.64 KB
  4.1 Collection Of Seed Samples 23
  4.2 Isolation Of Seed-Borne Mycoflora 23
  4.3 Seed Transmission Studies 24
  4.4 Pathogenicity Test 24
  4.5 Soil Used For Artificial Infestation 25
  4.6 Media Used 26
  4.7 In Vitro Interaction Between Killer Yeasts And Fusairum Spp. 27
  4.8 In Vivo Effect Of Killer Yeasts On Sunflower 29
  4.9 Bio-Control Experiments 29
  4.10 Detection Of Secondary Metabolites 31
  4.11 Spectral Analyses Of Secondary Metabolites 37
  4.12 Experimental Design And Analyses Of Data 37
6 5 Results 38
631.64 KB
  5.1 Seed-Borne Fusarium Spp. 38
  5.2 Seed Transmission Studies 41
  5.3 Pathogenicity Of Fusarium Spp. 46
  5.4 In Vitro Interactions 55
  5.5 IN Vitro Effects Of Antagonistic Killer Yeasts 59
  5.6 Biological Control Of Fusarium Spp. 61
  5.7 Secondary Metabolites Of Fusarium Spp. 72
7 6 Discussion 108
122.85 KB
8 7 References 139
538.57 KB
  7.1 Plates (1-5) 139
9 8 Acknowledgments 144
15.44 KB
10 9 Annexures 145
75.4 KB