Management of bhendi yellow vein mosaic virus using beneficial fungal root endophyte Piriformospora indica
| dc.contributor.advisor | Joy, M | |
| dc.contributor.author | Chippy. | |
| dc.date.accessioned | 2021-07-13T05:26:53Z | |
| dc.date.available | 2021-07-13T05:26:53Z | |
| dc.date.issued | 2020 | |
| dc.description | PG | en_US |
| dc.description.abstract | The study entitled ‘Management of Bhendi yellow vein mosaic virus using beneficial fungal root endophyte Piriformospora indica’ was conducted at College of Agriculture, Vellayani during 2018 - 2020 with the objective to evaluate beneficial fungal root endophyte, P. indica for the management of Bhendi yellow vein mosaic virus (BYVMV) and to elucidate the role of antioxidants in the tripartite interaction. BYVMV infected okra samples were collected from okra fields of 3 different locations of Thiruvananthapuram district viz., Vellayani, Pappanchani and Palappur. All the surveyed fields were severely infected and the highest disease incidence (D. I.) of 100% and vulnerability index (V. I.) of 71.07 was recorded in okra var. Kiran in Palappur. Characteristic symptoms observed in the surveyed locations include vein clearing, vein thickening, reduction in leaf size, stunted growth and reduced fruit set, fruits if formed were bleached, hardened and deformed. Vein clearing on flower buds was also observed. Total DNA of infected plant samples were isolated using Qiagen’s DNeasy Plant DNA extraction Mini Kit. The quantity and quality of DNA was assessed. The presence of the virus in the diseased samples were confirmed at molecular level by PCR using Deng and AV/AC primers specific to coat protein (CP) of BYVMV (Begomovirus) that could produce amplicons of 500 bp and 550 bp respectively in all infected samples. The pollen collected from the infected plants also produced amplicons confirming the presence of the virus. In vitro co-cultivation studies of P. indica in okra seedlings var. Salkeerthi in PNM medium revealed the fungal colonisation and formation of chlamydospores 25 days after co-cultivation. P. indica-colonisation enhanced shoot and root biomass; and produced more number of secondary roots. A pot culture experiment was conducted to evaluate the effect of P. indica-priming okra var. Salkeerthi under natural incidence of BYVMV. P. indica-priming significantly reduced the D. I. by 57 and V. I. by 56 per cent over control and also enhanced plant growth with increased root and shoot biomass, leaf area and plant height. There was 48 and 62 per cent increase in root and shoot fresh weight respectively in P. indica-colonised plants over control. Biochemical analysis of P. indica-primed and non-primed plants under natural incidence of BYVMV revealed increase in chlorophyll and total soluble proteins, and high activities of antioxidant enzymes in P. indica colonised plants. Total chlorophyll content was highest (1.32 mg g-1 fw) in P. indica-primed plants and least in BYVMV infected plants (0.20 mg g-1 fw). There was a 3-fold increase in total chlorophyll content in P. indica-primed plants under natural incidence compared to the diseased control. Chlorophyll b content was drastically reduced in diseased plants but P. indica-priming resulted in 3.2-fold increase in chlorophyll b. Total soluble protein content was increased by 121 per cent in P. indica-primed plants. Peroxidase (PO) and polyphenol oxidase (PPO) activities were increased by 94 per cent and 226 per cent respectively. There was 48 per cent increase in activities of both catalase and ascorbic acid oxidase in P. indica -primed plants over the diseased control. The decreased disease incidence and severity are attributed to the increased activities of antioxidant enzymes viz., peroxidase, polyphenol-oxidase, catalase and ascorbic acid oxidase. Effect of P. indica-priming (pre- and post- inoculation) on artificial inoculation of the virus by grafting was also evaluated. Both pre- and post-inoculation of the fungus in artificially infected okra plants reduced the V. I. by 56 and 24 per cent respectively. Similar trend as in case of natural incidence was also observed in biochemical activities in P. indica-primed okra plants under artificial inoculation. In pre-inoculation of P. indica followed by graft transmission of the virus, total chlorophyll and soluble protein contents were increased by 176 and 147 per cent respectively; PO and PPO activities by 109 and 176 per cent respectively; and catalase and ascorbic acid oxidase by 96 and 56 per cent respectively over the diseased control. Phosphatase activity was drastically decreased in the virus infected plants. The biochemical activities were significantly increased in post-inoculation of the fungus, but were not substantially as in the pre-inoculation followed by grafting of the virus. Thus, the present study revealed that P. indica could be exploited for the management of BYVMV on a prophylactic basis. Remission of the symptom in P. indica-colonised okra plants was attributed to the enhanced chlorophyll, soluble proteins, PO, PPO, catalase and ascorbic acid oxidase. Further studies should be conducted to elucidate the role of other antioxidants, and molecular mechanisms involved in this host-endophyte-virus interactions. Field and multi-locational studies should also be conducted for confirmation of the results. | en_US |
| dc.identifier.citation | 174971 | en_US |
| dc.identifier.uri | https://krishikosh.egranth.ac.in/handle/1/5810170435 | |
| dc.keywords | Plant Pathology | en_US |
| dc.language.iso | English | en_US |
| dc.pages | 80p. | en_US |
| dc.publisher | Department of Plant Pathology, College of Agriculture, Vellayani | en_US |
| dc.sub | Plant Pathology | en_US |
| dc.theme | Management of Bhendi yellow vein mosaic virus | en_US |
| dc.these.type | M.Sc | en_US |
| dc.title | Management of bhendi yellow vein mosaic virus using beneficial fungal root endophyte Piriformospora indica | en_US |
| dc.type | Thesis | en_US |