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PATHOGENIC EFFECTS AND PROFILES OF SECONDARY METABOLITES OF SEED-BORNE TOXIGENIC FUSARIUM SPECIES

Nahar, Sharfun (2002) PATHOGENIC EFFECTS AND PROFILES OF SECONDARY METABOLITES OF SEED-BORNE TOXIGENIC FUSARIUM SPECIES. PhD thesis, University of Karachi, Karachi.

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Abstract

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.

Item Type:Thesis (PhD)
Uncontrolled Keywords:metabolites, toxigenic fusarium species, seed-borne, seed-borne mycoflora, artificial infestation, killer yeasts, fusairum spp, secondary metabolites
Subjects:Biological & Medical Sciences (c) > Biological Sciences(c1) > Paleo-botany(c1.9)
ID Code:499
Deposited By:Mr. Muhammad Asif
Deposited On:07 Aug 2006
Last Modified:04 Oct 2007 21:01

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