RNAi mediated broad spectrum resistance against begomoviruses of okra (Abelmoschus esculentus L.)

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dc.contributor.advisorSarao, Navraj Kaur
dc.contributor.authorSharma, Nity
dc.date.accessioned2020-12-17T04:26:01Z
dc.date.available2020-12-17T04:26:01Z
dc.date.issued2020
dc.description.abstractOkra is an important vegetable crop of Malvaceae family and grown widely in tropical and subtropical areas of the world. Yellow vein, leaf curl and mosaic diseases caused by begomoviruses have emerged as most devastating viral diseases of okra. In the present investigation, RNA interference (RNAi) strategy was employed to control okra-infecting begomoviruses. For this, two hairpin RNAi constructs harbouring overlapping regions of AC1/AC2 and AC1/AC4 genes of DNA-A genome of begomoviruses of okra were generated. Consecutively, agroinfectious clone harbouring dimeric units of whole genome clone of okrainfecting begomoviruses was also generated. Efficacy of three constructs was checked by transient assay and plants having RNAi constructs did not show any symptoms after four weeks of agroinfilteration as compared to plants inoculated with agroinfectious clone. Further, Agrobacterium- mediated tissue culture dependent protocol was utilized to generate transgenic okra plants of variety Punjab 8 expressing AC1/AC2-hp and AC1/AC4-hp RNA. Hypocotyls were used as explants for transformation and a cytokinin named trans-zeatin riboside of 2mg/l concentration was used for regeneration of plantlets. Transgenic plants were assayed for resistance to okra-infecting begomoviruses using agro-infectious clone and viruliferous whiteflies. Nearly 90% resistance against begomovirus infection was observed in transgenic lines when compared with untransformed plants and the plants transformed with empty vectors. Control plants developed severe viral disease symptoms within 4 weeks. Out of eleven plants, one plant expressing AC1/AC4-hp RNAi constructs displayed appearance of milder symptoms after 6 weeks when attacked with viruliferous whiteflies. The resistant transgenic lines accumulated very low titres of viral DNA. Plants thus formed had normal phenotype with no yield penalty in greenhouse conditions.en_US
dc.identifier.citationSharma, Nity (2020) RNAi mediated broad spectrum resistance against begomoviruses of okra (Abelmoschus esculentus L.) (Unpublished Ph.D. Dissertation). Punjab Agricultural University, Ludhiana, Punjab, India.en_US
dc.identifier.urihttps://krishikosh.egranth.ac.in/handle/1/5810156796
dc.keywordsRNAi, Genetic transformation, Agrobacterium, AC1/AC2 genes, AC1/AC4 genesen_US
dc.language.isoEnglishen_US
dc.pages117en_US
dc.publisherPunjab Agricultural University, Ludhianaen_US
dc.research.problemRNAi mediated broad spectrum resistance against begomoviruses of okra (Abelmoschus esculentus L.)en_US
dc.subAgricultural Biotechnologyen_US
dc.themeRNAi mediated broad spectrum resistance against begomoviruses of okra (Abelmoschus esculentus L.)en_US
dc.these.typePh.Den_US
dc.titleRNAi mediated broad spectrum resistance against begomoviruses of okra (Abelmoschus esculentus L.)en_US
dc.typeThesisen_US
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