Pathogenic and genetic diversity of Xanthomonas oryzae pv. oryzae isolates from Chhattisgarh, host plant resistance and biological management of bacterial blight of rice
| dc.contributor.advisor | Khare, N. | |
| dc.contributor.advisor | Laha, G.S. | |
| dc.contributor.advisor | Lakpale, N. | |
| dc.contributor.advisor | Saxena, R.R. | |
| dc.contributor.advisor | Sharma, R.N. | |
| dc.contributor.author | Sahu, Bhimeshwari | |
| dc.date.accessioned | 2019-03-15T09:29:00Z | |
| dc.date.available | 2019-03-15T09:29:00Z | |
| dc.date.issued | 2018 | |
| dc.description | Pathogenic and genetic diversity of Xanthomonas oryzae pv. oryzae isolates from Chhattisgarh, host plant resistance and biological management of bacterial blight of rice | en_US |
| dc.description.abstract | The present investigation was carried out in the laboratory and glass house in year 2016-2018 at Department of Plant Pathology, Indian Institute of Rice Research (IIRR), Hyderabad. Rice (Oryza sativa) is the world’s most important food crop and staple food for more than half of human population. Being the most important crop in India, rice occupies the pivotal place in Indian agriculture. Rice is the major crop of Chhattisgarh during kharif season. One of the major biotic production constraints in rice is bacterial blight (BB), caused by Xanthomonas oryzae pv. oryzae (Xoo) and the extent of yield loss may be as high as 50% or more. Analysis of disease survey data for the last 34 years in various rice growing states of India revealed that the disease has increased both in terms of geographical distribution and intensity and moved to areas which were earlier not considered as endemic for the disease. The pathogen is highly dynamic in nature and knowledge on pathogen population structure is imperative for designing a scientific resistance breeding program. A total of 60 Xoo isolates collected from different rice growing districts of Chhattisgarh were analyzed for their pathogenic and genetic variability. The isolates were grouped into 9 pathotypes based on their reaction on a set of rice differentials (IRBB lines having different BB resistance genes and their combination in the genetic background of IR24). Some pathotypes were detected which individually could overcome the resistance of major BB resistance genes, xa13 and Xa21. Molecular characterization of these Xoo isolates using primers (pJEL1 & pJEL2 and J3 primers) based on IS element (IS1112 and IS1113) revealed a high degree of genetic diversity among the Xoo isolates. As the disease cannot be managed very effectively chemically, an attempt was made to isolate antagonistic microbes from the rice rhizosphere and other sources. A total of 21 fluorescent pseudomonads isolates and 140 isolates of Bacillus spp. were isolated from different sources and evaluated for their antagonistic potential against Xoo. All the 21 isolates fluorescent pseudomonads and 74 isolates of Bacillus spp. showed typical inhibition zone against Xoo. Selected isolates of fluorescent pseudomonads and Bacillus spp. significantly reduced the bacterial blight disease severity under glasshouse condition when applied through seed treatment and spraying. Biochemical characterization of these isolates revealed that most of the fluorescent pseudomonad isolates belonged to Pseudomonas fluorescens and some of the Bacillus spp. were identified as Bacillus subtilis. The PGP activity of fluorescent pseudomonads and Bacillus spp exhibited significantly positive response as compare to control. The antagonistic activity of the isolates of fluorescent pseudomonads might be due to the production of HCN or synergistic interaction with other metabolites. All the isolates of fluorescent pseudomonads and Bacillus spp. exhibited ability to solubilise phosphate when spot inoculated on Pikovskaya’s medium. One of the major alternatives for the management of BB in rice is use of resistant varieties. A selected promising 36 entries from All India Coordinated Rice Improvement Project were evaluated with multiple Xoo isolates to study their resistance spectrum against bacterial blight. Out of 36 entries, 10 entries showed very broad spectrum resistance to BB to 7-8 Xoo isolates. When these lines were profiled for presence of different major BB resistance genes using gene-specific markers, one entry did not show presence of any known BB resistance genes though it showed high level of resistance to BB. The line may have novel source of resistance to BB. Overall, the study reveals that the Xoo isolates from Chhattisgarh are highly diverse. The study also revealed that selected biocontrol agents can be used for the management of the BB disease and the novel resistant line can be used for its genetics of resistance. | en_US |
| dc.identifier.uri | http://krishikosh.egranth.ac.in/handle/1/5810098651 | |
| dc.keywords | Bacterial Blight, Xanthomonas oryzae pv. oryzae, biological management | en_US |
| dc.language.iso | en | en_US |
| dc.pages | 261p. | en_US |
| dc.publisher | Indira Gandhi Krishi Vishwavidyalaya, Raipur | en_US |
| dc.research.problem | Pathogenic and genetic diversity of Xanthomonas oryzae pv. oryzae isolates from Chhattisgarh, host plant resistance and biological management of bacterial blight of rice | en_US |
| dc.sub | Plant Pathology | en_US |
| dc.subject | null | en_US |
| dc.theme | Pathogenic and genetic diversity of Xanthomonas oryzae pv. oryzae isolates from Chhattisgarh, host plant resistance and biological management of bacterial blight of rice | en_US |
| dc.these.type | Ph.D | en_US |
| dc.title | Pathogenic and genetic diversity of Xanthomonas oryzae pv. oryzae isolates from Chhattisgarh, host plant resistance and biological management of bacterial blight of rice | en_US |
| dc.type | Thesis | en_US |