33 research outputs found

    Opinion dynamics model with domain size dependent dynamics: novel features and new universality class

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    A model for opinion dynamics (Model I) has been recently introduced in which the binary opinions of the individuals are determined according to the size of their neighboring domains (population having the same opinion). The coarsening dynamics of the equivalent Ising model shows power law behavior and has been found to belong to a new universality class with the dynamic exponent z=1.0±0.01z=1.0 \pm 0.01 and persistence exponent θ0.235\theta \simeq 0.235 in one dimension. The critical behavior has been found to be robust for a large variety of annealed disorder that has been studied. Further, by mapping Model I to a system of random walkers in one dimension with a tendency to walk towards their nearest neighbour with probability ϵ\epsilon, we find that for any ϵ>0.5\epsilon > 0.5, the Model I dynamical behaviour is prevalent at long times.Comment: 12 pages, 10 figures. To be published in "Journal of Physics : Conference Series" (2011

    Marker-assisted enhancement of bacterial blight (Xanthomonas oryzae pv. oryzae) resistance in a salt-tolerant rice variety for sustaining rice production of tropical islands

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    IntroductionBacterial blight (BB) caused by Xanthomonas oryzae pv. oryzae is a major disease of rice, specially in the tropical regions of the world. Developing rice varieties with host resistance against the disease is the most effective and economical solution for managing the disease.MethodsPyramiding resistance genes (Xa4, xa5, xa13,and Xa21) in popular rice varieties using marker-assisted backcross breeding (MABB) has been demonstrated as a cost-effective and sustainable approach for establishing durable BB resistance. Here, we report our successful efforts in introgressing four resistance genes (Xa4, xa5, xa13, and Xa21) from IRBB60 to CARI Dhan 5, a popular salt-tolerant variety developed from a somaclonal variant of Pokkali rice, through functional MABB.Results and discussionBoth BB and coastal salinity are among the major challenges for rice production in tropical island and coastal ecosystems. Plants with four, three, and two gene pyramids were generated, which displayed high levels of resistance to the BB pathogen at the BC3F2 stage. Under controlled salinity microplot environments, the line 131-2-175-1223 identified with the presence of three gene pyramid (Xa21+xa13+xa5) displayed notable resistance across locations and years as well as exhibited a salinity tolerance comparable to the recurrent parent, CARI Dhan 5. Among two BB gene combinations (Xa21+xa13), two lines, 17-1-69-334 and 46-3-95-659, demonstrated resistance across locations and years, as well as salt tolerance and grain production comparable to CARI Dhan 5. Besides salinity tolerance, five lines, 17-1-69-179, 46-3-95-655, 131-2-190-1197, 131-2-175-1209, and 131-2-175-1239, exhibited complete resistance to BB disease. Following multilocation testing, potential lines have been identified that can serve as a prospective candidate for producing varieties for the tropical Andaman and Nicobar Islands and other coastal locations, which are prone to BB and coastal salinity stresses

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    Functional analysis of a susceptibility gene (HIPP27) in the Arabidopsis thaliana-Meloidogyne incognita pathosystem by using a genome editing strategy

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    Abstract Background Plant-parasitic root-knot nematodes cause immense yield declines in crop plants that ultimately obviate global food security. They maintain an intimate relationship with their host plants and hijack the host metabolic machinery to their own advantage. The existing resistance breeding strategies utilizing RNAi and resistance (R) genes might not be particularly effective. Alternatively, knocking out the susceptibility (S) genes in crop plants appears to be a feasible approach, as the induced mutations in S genes are likely to be long-lasting and may confer broad-spectrum resistance. This could be facilitated by the use of CRISPR/Cas9-based genome editing technology that precisely edits the gene of interest using customizable guide RNAs (gRNAs) and Cas9 endonuclease. Results Initially, we characterized the nematode-responsive S gene HIPP27 from Arabidopsis thaliana by generating HIPP27 overexpression lines, which were inoculated with Meloidogyne incognita. Next, two gRNAs (corresponding to the HIPP27 gene) were artificially synthesized using laboratory protocols, sequentially cloned into a Cas9 editor plasmid, mobilized into Agrobacterium tumefaciens strain GV3101, and transformed into Arabidopsis plants using the floral dip method. Apart from 1–3 bp deletions and 1 bp insertions adjacent to the PAM site, a long deletion of approximately 161 bp was documented in the T0 generation. Phenotypic analysis of homozygous, ‘transgene-free’ T2 plants revealed reduced nematode infection compared to wild-type plants. Additionally, no growth impairment was observed in gene-edited plants. Conclusion Our results suggest that the loss of function of HIPP27 in A. thaliana by CRISPR/Cas9-induced mutagenesis can improve host resistance to M. incognita
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