Molecular characterization of erwinia species causing rhizome rot in banana (Record no. 157974)
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| 000 -LEADER | |
|---|---|
| fixed length control field | 05549nam a22001697a 4500 |
| 082 ## - DEWEY DECIMAL CLASSIFICATION NUMBER | |
| Classification number | 660.6 |
| Item number | GEE/MO |
| 100 ## - MAIN ENTRY--PERSONAL NAME | |
| Personal name | Geethu Gokul G |
| 245 ## - TITLE STATEMENT | |
| Title | Molecular characterization of erwinia species causing rhizome rot in banana |
| 260 ## - PUBLICATION, DISTRIBUTION, ETC. (IMPRINT) | |
| Place of publication, distribution, etc | Vellanikkara |
| Name of publisher, distributor, etc | Centre for Plant Biotechnology and Molecular Biology, College of Horticulture |
| Date of publication, distribution, etc | 2017 |
| 300 ## - PHYSICAL DESCRIPTION | |
| Extent | 94p |
| 502 ## - DISSERTATION NOTE | |
| Dissertation note | MSc |
| 520 3# - SUMMARY, ETC. | |
| Abstract | The rhizome rot or tip over disease affecting the rhizome caused by Erwinia spp. is a major and emerging issue which leads to a substantial economic loss in banana. The widely cultivatedbanana varieties like Grand Naine, Rasthali and Nendran are very susceptible to the disease. Different Erwinia species are reported to cause the disease. Understanding the correct etiology of the disease and variability of the pathogen based on molecular characterization is very much important in crop improvement programmes. Isolation of pathogen from infected rhizomes from different locations yielded 18 bacterial isolates. In nutrient agar medium, the bacterial colonies were small, cream to yellow in colour, slightly raised and mucoid.The bacterium when streaked on the crystal violet pectate medium produced fissures or pits characteristic of Pectobacterium spp. The pathogenicity tests were carried out by inoculation in rhizome bits (in-vitro), rhizome of three months old plants (in-vivo) and pseudostem of two months old tissue culture plants (in-vivo) of banana var. Nendran. Inoculation of rhizome bits and inoculation at collar region of three months old banana plants produced rotting symptoms after eight and 37 days respectively. Pseudostem inoculation of two months old tissue culture plants var. Nendran also produced characteristic rotting symptoms after six days. After proving pathogenicity, the 18 bacterial isolates were characterized by cultural, morphological, biochemical, physiological and molecular methods. Cultural characterization was carried out by using nutrient agar (NA), yeast extract glucose calcium carbonate (YGC), Logan’s medium and nutrient broth. On nutrient agar, cream to slightly yellowish, mucoid, slightly raised convex colonies with entire margin varying in size were formed. The bacterial growth in the nutrient broth was recorded at different intervals and variation in OD values was observed between isolates. On YGC medium, cream to yellow coloured semi mucoid colonies were formed with a clear zone around each colony after 24 h of inoculation. Small bubbles were observed on the top of each bacterial colony due to the emission of CO2 which is the characteristic feature of Pectobacterium spp. In Logan’s medium small to medium colonies of 1.6 to 2 mm diameter with purple colour colonies were formed, which is the characteristic feature of Erwinia carotovora/Pectobacteriumcarotovorum. Morphological characterization of the bacterium was carried out by staining viz., Gram staining, capsule staining, flagellar staining. The bacteria appeared as red coloured short rods indicating the Gram negative nature with 3.10 μm-0.95 μm x 1.10 μm-0.57 μm in size. The bacterium was non-capsular in nature with peritrichous flagella. Biochemical characterization of the bacterial isolates were carried out by conducting different test viz., solubility in KOH, potato soft rot test, carrot soft rot test, intrinsic antibiotic resistance, growth in three and four per cent NaCl, growth in CVP medium and catalase test. The bacteria, in three per cent KOH produced viscous filament. The potato and carrot slices inoculated with bacterial culture produced rotting symptoms with the emission of characteristic foul smell in three to four days and five to seven days respectively and variation was observed between isolates. The bacterial isolates showed resistance to erythromycin and susceptibility to streptomycin. Bacterial growth was observed in the inoculated peptone broth containing three and four percent NaCl. The bacterial culture inoculated on CVP medium produced characteristic fissures or depressions due to pectate degradation. Catalase test was positive for all the isolates. Physiological characterization of the bacterium was carried out by growing at different temperature and pH. The maximum growth was recorded at 27oC and at pH 7.0. Based on the results of cultural, morphological, biochemical and physiological characterization of the 18 bacterial isolates, dendrogram was constructed which classified the isolates into six groups. The molecular characterization of bacterial isolates was carried out by total genomic DNA isolation, PCR amplification of 16S rRNA gene and sequencing. Colony PCR of 18 bacterial isolates were also carried out. The sequences obtained for six isolates, representative of each group were used for homology analysis, phylogenetic analysis and phylogenetic tree construction. All the six groups of bacterial isolates were belonged to Pectobacterium carotovorum but variation was observed at subspecies level. Out of the six groups, there were two subspecies viz., Pectobacterium carotovorum ssp. carotovorum and Pectobacterium carotovorum ssp. brasiliense. The Barcode gap of Pectobacterium carotovorumandPectobacteriumcarotovorumssp.brasiliense sequences were deposited in the NCBI GenBank. carotovorum was assessed ssp. and the |
| 650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM | |
| Topical term or geographic name as entry element | Plant Biotechnology and Molecular Biology |
| 700 ## - ADDED ENTRY--PERSONAL NAME | |
| Personal name | Vimi Louis (Guide) |
| 856 ## - ELECTRONIC LOCATION AND ACCESS | |
| Uniform Resource Identifier | http://krishikosh.egranth.ac.in/handle/1/5810132644 |
| 942 ## - ADDED ENTRY ELEMENTS (KOHA) | |
| Source of classification or shelving scheme | |
| Item type | Theses |
| Not for loan | Collection code | Permanent location | Current location | Shelving location | Date acquired | Full call number | Barcode | Date last seen | Koha item type |
|---|---|---|---|---|---|---|---|---|---|
| Not For Loan | Reference Book | KAU Central Library, Thrissur | KAU Central Library, Thrissur | Theses | 2017-12-27 | 660.6 GEE/MO | 174093 | 2017-12-27 | Theses |