MOLECULAR VARIABILITY AND MANAGEMENT OF XANTHOMONAS CITRI SUBSP. CITRI CAUSING CITRUS BACTERIAL CANKER

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dc.contributor.advisorMonica Sharma
dc.contributor.authorDINESH KUMAR
dc.date.accessioned2024-06-26T14:08:37Z
dc.date.available2024-06-26T14:08:37Z
dc.date.issued2024-06-14
dc.description.abstractThe present investigation entitled “Molecular variability and management of Xanthomonas citri subsp. citri causing citrus bacterial canker” was undertaken to record the amount of molecular variability exists in different isolates of the pathogen and different management strategies were assessed for the management of the disease. Different isolates of the pathogen were collected from four districts (Hamirpur, Una, Sirmour and Kangra) of Himachal Pradesh and one was collected form Punjab and one from Karnataka. The isolates were isolated from different hosts such as Citrus sinensis, C. reticulata, C. aurantifolia, C. limon and C. jambhiri. The isolates exhibited variable colony colour from yellow, light yellow, dark yellow and pale colour on nutrient agar medium. The variation in incubation period of isolates ranged from 2.2 to 4.4 days, in final symptom development period ranged from 19.6 to 24 days and in per cent disease index ranged from 40 to 90 per cent in detached leaf pathogenicity assay. The isolates showed variation under attached leaf pathogenicity assay on seedlings of sweet orange and incubation period ranged from 7.2 to 10.4 days and final symptoms development ranged from 32.4 to 40 days and per cent disease index varied from 37.50 to 79.17 days. Molecular identification confirmed the presence of single band in all isolates for 16S rDNA at 591 bp, for glpF gene two isolates with a single band at 690 bp and for species specific rpf gene in seven isolates producing single band near 581 bp. Moleclar variability among isolates was confirmed by using RAPD and ISSR markers which showed high amount of genetic variability among the isolates and both markers were polymorphic in nature. Both the markers clustered the isolates in three groups and combined clustering grouped them in two groups. For disease management, different resistance inducing chemicals at three different concentrations were analysed and salicylic acid, β-amino butyric acid, acibenzolar -S- methyl and potassium chloride were effective and effectiveness increased from low to high concentration of chemicals. All these chemicals were found to improve the plant’s phenolic and chlorophyll content and the peroxidase, polyphenol oxidase and phenylalanine ammonia lyase activity was also enhanced with their application in comparison to inoculated control, un-inoculated control and other treatments. Green silver and copper nanoparticles using leaf extract exhibited the effectiveness for inhibition of the pathogen as well as disease under semi-controlled conditions with highest efficacy in green silver nanoparticles of Ocimum sanctum and Tagetes erecta followed by green copper nanoparticles of Eucalyptus hybrida. Metal nanoparticles were effective in disease management under controlled conditions and pathogen inhibition under in vitro conditions.
dc.identifier.urihttps://krishikosh.egranth.ac.in/handle/1/5810210949
dc.keywordsCITRI CAUSING CITRUS BACTERIAL CANKER
dc.keywordsMOLECULAR VARIABILITY AND MANAGEMENT OF XANTHOMONAS CITRI SUBSP
dc.language.isoEnglish
dc.pages121+xiv
dc.publisherUHF Nauni
dc.subPlant Pathology
dc.themeMolecular variability and management of Xanthomonas citri subsp. citri causing citrus bacterial canker
dc.these.typePh.D
dc.titleMOLECULAR VARIABILITY AND MANAGEMENT OF XANTHOMONAS CITRI SUBSP. CITRI CAUSING CITRUS BACTERIAL CANKER
dc.typeThesis
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