Bacterial wilt (causal organism-Ralstonia solanacearum) is one of the most important soil-borne diseases of eggplant (Solanum melongena) worldwide. The best way to control it economically is to develop cultivars resistant to this soil-borne pathogen. Resistance gene (R-gene) cloning and sequencing to obtain resistance gene analogs (RGAs) is one of the most recent approaches for obtaining disease resistant cultivars. Three different types of degenerative PCR based primers were used for isolating RGAs from resistant cultivated/ wild species through amplification of the target region of nucleotide binding site-leucine rich repeat (NBS-LRR). Genetic diversity was observed in the sequences isolated, and six sequences showing specific conserved motifs were shortlisted as Solanum melongena RGAs (Sm7RGA1, Sm7RGA2, Sm7RGA4, Sm7RGA8 and Sm7RGA10) and Solanum viarum RGA (SvRGA2). The RGAs isolated in this study belong to both toll interleukin-1 receptors (TIR)-NBS-LRR and non-TIR-NBS-LRR type R-genes and show similarity with other plant resistance genes. This study also confirmed the hypothesis that dicots have both TIR and non-TIR resistance genes. The present study on eggplant RGAs will help develop RGA based markers linked to bacterial wilt in eggplant and other plant species. Further, it will provide information and pave the way for elucidation at the molecular level of wild and cultivated species' mechanism of resistance to bacterial wilt. This is the first report of NBS-LRR class resistance genes/RGA in resistant eggplant and its wild relatives against bacterial wilt (BW).

In the past few years, nanoparticles have been applied in various fields of science and technology, ranging from material science to biotechnology. Thus, the synthesis of nanoparticles can be considered as a dynamic area in research and application of nanoparticles. The different methods of nanoparticle synthesis include physical, chemical and biological methods. Of these methods, the biological synthesis is to be comparatively widely used due to its advantages of being low cost, non-toxic and environmental friendly. Bioapplications of nanoparticles have pawed way for green synthesis of nanoparticles. In this review, we have provided brief information on various biological agents used for the synthesis of nanoparticles.The various methods for nanoparticles synthesis are categorized mainly under physical, chemical and biological synthesis. Each of these methods has its advantages and disadvantages in terms of yield potential, scalability, particle size and distribution, shape uniformity and costs involved. Physical synthesis of nanoparticles:Nanoparticles of various materials, such as silver, gold, lead sulfide (PbS), fullerene, etc, have been produced using the evaporation/condensation technique [4]. The physical methods for nanoparticles synthesis include thermolysis, physical vapor deposition (PVD) [5], pulsed laser method [6], microwave-assisted synthesis [7], high-energy ball milling [8], melt mixing [9], laser ablation [10], ion implantation [11], sputter deposition [12], electric arc deposition [13],etc. Each of these techniques alters one physical parameter; for example, temperature is altered in thermolysis, pressure in ball milling, pH in ion implantation, radiations in laser ablation, etc. The desired size and shape of the nanoparticles can be obtained by optimizing and maintaining the optimized parameters. However, the main drawbacks of physical methods include high costs of equipments, time-consuming procedures, and elevated parameters that are not favorable to the natural environment, but the advantage of this method is that it can help obtain uniform shape and size of nanoparticles. Chemical synthesis of nanoparticlesChemical synthesis is one of the most widely used methods of producing large quantities of nanoparticles within a short span [14]. These methods include the sol-gel process [15], co-precipitation [16], chemical vapor deposition [17], radio-frequency plasma method [18], and solvo-thermal synthesis [19]. These methods require strong reducing agents for the reduction of nanoparticles and capping agents, such as triethanolamine, oleic acid and thioglycerol, [20] for size control and stabilization of the synthesized nanoparticles. The main disadvantages of chemical methods include high toxicity and cost of chemicals used.

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Viruses are serious threat to chilli crop production worldwide. Resistance screening against several viruses resulted in identifying a multiple virus resistant genotype 'IHR 2451'. Degenerate primers based on the conserved regions between P-Loop and GLPL of Resistance genes (R-genes) were used to amplify nucleotide binding sites (NBS)-encoding regions from genotype 'IHR 2451'. Alignment of deduced amino acid sequences and phylogenetic analyses of isolated sequences distinguished into two groups representing toll interleukin-1 receptor (TIR) and non-TIR, and different families within the group confirming the hypotheses that dicots have both the types of NBS-LRR genes. The alignment of deduced amino acid sequences revealed conservation of subdomains P-loop, RNBS-A, kinase2, RNBS-B, and GLPL. The distinctive five RGAs showing specific conserved motifs were subjected to BLASTp and indicated high homology at deduced amino acid level with R genes identified such as Pvr9 gene for potyvirus resistance, putative late blight resistance protein homolog R1B-23 and other disease resistance genes suggesting high correlation with resistance to different pathogens. These pepper RGAs could be regarded as candidate sequences of resistant genes for marker development.

Cauliflower (Brassica oleracea) is a cool-season crop belonging to the Brassicaceae family. Use of morphological differences between true-to-types and off-types in grow-out test (GOT) is the basic method for hybrid purity analysis. Traditional GOT is costly, tedious, time consuming and environment sensitive. To increase the speed and accuracy of genetic purity testing of hybrids, recent advances in DNA markers have shown promise. In the present study, the purity of cauliflower hybrid (NBH Tania-815) was assessed by traditional GOT and advanced molecular marker systems. The experiment was carried out by mixing 95% F 1 hybrids with 5% female parents, individually in the sample sets of 400, 300, 200, 100, 80 and 40. For each sample size, PCR-based assay and GOT were carried out to check the hybrid purity. In the PCR-based assay, 220 pairs of SSR markers were screened, with 32 markers showing parental polymorphism including one codominant marker (BrgMS565). The purity level was determined by the co-dominant marker. A minimum sample size of 100 was standardized to confirm the hybrid purity as it showed the same result with that of higher sample sizes (200, 300 and 400). Hence, it is proposed that molecular marker-based hybrid purity assessment may serve as an effective substitute to traditional GOT.