Antimicrobial Resistance with Special Emphasis on Pathogens in Agriculture

Antibiotics have been used globally to manage the bacterial plant diseases irrespective of the expense involved. Although plant pathogenesis by bacteria is far lower than fungal counterparts, disrupted monitoring and surveillance for drug resistance with respect to human health raise serious concerns. The resistance derived by the plant as the host by the antibiotics used for many generations has now posed as a problem in phyto-systems. Although we currently lack the molecular understanding of the pathogens rendering antibiotic resistance to plants, robust resistance management strategies are critical to ensure management of critically important diseases that specifically target crops of high value and/or global agrarian importance. This chapter discusses evolution of plant-pathogenic bacteria, application of antibiotics and its repercussions on the microbiome of plant agricultural systems, and sustainable crop disease management by genetic engineering

biological mediated ag nanoparticles from barleria longiflora for antimicrobial activity and photocatalytic degradation using methylene blue

AbstractThe present study focuses on extraction of green synthesized silver nanoparticles (Ag-NPs) from Barleria longiflora L. leaves for antibacterial and photocatalytic activities. The extracted Ag-NPs have been characterized by XRD, FTIR, FE-SEM with EDX, HR-TEM accompanied SAED pattern and UV-Visible absorption spectroscopic techniques. Spectral studies confirmed the UV-Visible absorption spectrum of the Ag-NPs at a wavelength of 443 nm and a good crystalline nature with a face-centered cubic crystal structure using XRD spectrum. Surface topography and the presence of Ag in the prepared sample have been confirmed from SEM and EDX measurements. Various functional groups present in the sample have been examined using FT-IR spectroscopic analysis. A homogeneous dispersion of spherical form nanoparticles with a usual size of 2.4 nm was confirmed by visualization using FE-SEM and HR-TEM. Moreover, Ag-NPs stimulate a strong inhibition of Enterococcus sp., Streptococcus sp, Bacillus megaterium, Pseudomonas p..

Over-expression of Topoisomerase II Enhances Salt Stress Tolerance in Tobacco

Topoisomerases are unique enzymes having an ability to remove or add DNA supercoils and untangle the snarled DNA. They can cut, shuffle and religate DNA strands and remove the torsional stress during DNA replication, transcription or recombination events. In the present study, we over-expressed topoisomerase II (TopoII) in tobacco (Nicotiana tabaccum) and examined its role in growth and development as well as salt (NaCl) stress tolerance. Several putative transgenic plants were generated and the transgene integration and expression was confirmed by PCR and Southern blot analyses, and RT-PCR analysis respectively. Percent seed germination, shoot growth and chlorophyll content revealed that transgenic lines over-expressing the NtTopoIIα-1 gene exhibited enhanced tolerance to salt (150 and 200 mM NaCl) stress. Moreover, over-expression of TopoII lead to the elevation in proline and glycine betaine levels in response to both concentrations of NaCl as compared to wild-type. In response to NaCl stress, TopoII over-expressing lines showed reduced lipid peroxidation derived malondialdehyde (MDA) generation. These results suggest that TopoII plays a pivotal role in salt stress tolerance in plants

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Not Available: Isolation of high quality, intact high molecular weight genomic DNA from plants which are rich in polysaccharides, polyphenols, secondary metabolites and chemical heterogeneity is an immense problem in the field of plant biology. Several protocols have been developed for eliminating these tricky elements during the extraction of DNA, but none is found to be universally applicable. The purpose of the present study was to develop a reliable protocol for extracting high quality genomic DNA from polyphenols, polysaccharides and secondary metabolites rich plants like sweet sorghum. We made seven critical modifications to the available CTAB method to isolate genomic DNA from 25- and 60-d-old transgenic sweet sorghum leaf tissues. The yield of DNA ranged from 9.2– 10.2 µg from 200 mg of leaf tissue. An absorbance value of 1.8 at A260/A280 indicates that it’s free from RNA and protein contamination. PCR analysis using bar primers shows a consistent and reliable amplification product at 475 bp. This method is highly suitable for extracting high quality genomic DNA from plants with high levels of polysaccharides and polyphenolics without blending commercial kits. Our protocol facilitates the processing of large number of plant samples for genomic analysis, mapping and next generation sequencing.Not Availabl

A Simple and Efficient Method for High Quality DNA Extraction from Sweet Sorghum [Sorghum bicolor (L.) Moench]

Not AvailableIsolation of high quality, intact high molecular weight genomic DNA from plants which are rich in polysaccharides, polyphenols, secondary metabolites and chemical heterogeneity is an immense problem in the field of plant biology. Several protocols have been developed for eliminating these tricky elements during the extraction of DNA, but none is found to be universally applicable. The purpose of the present study was to develop a reliable protocol for extracting high quality genomic DNA from polyphenols, polysaccharides and secondary metabolites rich plants like sweet sorghum. We made seven critical modifications to the available CTAB method to isolate genomic DNA from 25- and 60-d-old transgenic sweet sorghum leaf tissues. The yield of DNA ranged from 9.2– 10.2 µg from 200 mg of leaf tissue. An absorbance value of 1.8 at A260/A280 indicates that it’s free from RNA and protein contamination. PCR analysis using bar primers shows a consistent and reliable amplification product at 475 bp. This method is highly suitable for extracting high quality genomic DNA from plants with high levels of polysaccharides and polyphenolics without blending commercial kits. Our protocol facilitates the processing of large number of plant samples for genomic analysis, mapping and next generation sequencing.Not Availabl

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Not Availablepost green revolution agriculture is based on generous application of fertilizers and high-yielding genotypes that are suited for such high input regimes. Cereals, like maize (Zea mays L.) are capable of utilizing less than 20% of the applied inorganic phosphate (Pi) - a non-renewable fertilizer resource. A greater understanding of the molecular mechanisms underlying the acquisition, transportation and utilization of Pi may lead to engineering genotypes with high phosphorus use efficiency. In this study, we carried out functional domain similarity analysis, promoter analysis and comparative transcriptional expression profiling of 12 selected Pi responsive genes in the Pi stress tolerant maize inbred line HKI-163 under sufficient and deficient Pi conditions. Pi starvation led to significant increase in root length; marked proliferation of root hairs and lesser number of crown roots. Eleven genes were significantly up or down regulated in Pi deficient condition. The putative acid phosphatase, ZmACP5 expression was up regulated by 162.81 and 74.40 fold in root and leaf tissues, respectively. The RNase, ZmRNS1 showed 115 fold up regulation in roots under Pi deprivation. Among the two putative high affinity Pi transporters ZmPht1;4 was found specific to root, whereas ZmPht2 was found to be up regulated in both root and leaf tissues. The genes involved in Pi homeostasis pathway (ZmSIZ1, SPX1 and Pho2) were up regulated in root and leaf. In light of the expression profiling of selected regulatory genes, an updated model of transcriptional regulation under Pi starvation in maize has been presented.Not Availabl

A high-throughput genome-walking method and its use for cloning unknown flanking sequences

We developed a PCR-based high-throughput genome-walking protocol. The novelty of this protocol is in the random introduction of unique walker primer binding sites into different regions of the genome efficiently by taking advantage of the rolling circle mode of DNA synthesis by Phi29 DNA polymerase after annealing the partially degenerate primers to the denatured genomic DNA. The inherent strand-displacement activity of the Phi29 DNA polymerase displaces the 5' ends of downstream strands and DNA synthesis continues, resulting in a large number of overlapping fragments that cover the whole genome with the unique walker adapter attached to the 5' end of all the genomic DNA fragments. The directional genome walking can be performed using a locus-specific primer and the walker primer and Phi29 DNA polymerase-amplified genomic DNA fragments as template. The locus-specific primer will determine the position and direction of the genome walk. Two rounds of successive PCR amplifications by locus-specific and walker primers and their corresponding nested primers effectively amplify the flanking DNA fragments. The desired PCR fragment can be either cloned or sequenced directly using another nested, locus-specific primer. We successfully used this protocol to isolate and sequence 5' flanking regions/promoters of selected plant genes

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Not AvailableMaize is an important crop for billions of people as food, feed, and industrial raw material. It is a prime driver of the global agricultural economy as well as the livelihoods of millions of farmers. Genetic interventions, such as breeding, hybridization and transgenesis have led to increased productivity of this crop in the last 100 years. The technique of genome editing is the latest advancement in genetics. Genome editing can be used for targeted deletions, additions, and corrections in the genome, all aimed at genetic enhancement of crops. The Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR associated protein 9 (CRISPR/Cas9) system is a recent genome editing technique that is considered simple, precise, robust and the most revolutionary. This review summarizes the current state of the art and predicts future directions in the use of the CRISPR/Cas9 tool in maize crop improvement.Not Availabl