Evaluation of Cultivated and Wild Brinjal Germplasm against Bacterial Wilt Disease with Tollinterleukin-1 Receptors (TIR)-NBS-LRR Type R-gene Specific Degenerate Primer

The experiment was conducted at C-Block Farm of Bidhan Chandra Krishi Viswavidyalaya, Kalyani, West Bengal, India during 2017–18 to screen eight brinjal germplasm lines against BW disease using tollinterleukin-1 receptors (TIR)-NBS-LRR type R-gene specific degenerate primer. The study showed that wild genotype S. torvum was highly resistant to bacterial wilt incidence with no wilting symptom whereas two cultivated genotypes (Utkal Anushree and Utkal Madhuri) and one wild genotype S. sisymbriifolium were found to be resistant to BW disease. Out of the 7 germplasm sequences, 2 had no match with R-genes whereas the remaining 5 sequences have 70-93% homology with R-genes of other plant species submitted in Gene Bank sequence database. Nearly 90% sequence identity of brinjal NBS-LRR RGA was found by analyzing through BLASTn with NBS-LRR RGAs of other solanaceous crops. Two cultivated resistant genotypes (Utkal Madhuri and Utkal Tarini) were similar to the wild resistant type S. sisymbriifloium, while cultivable resistant genotype Utkal Anushree was highly different at sequence level. Two cultivable susceptible genotypes (BCB-30 and Garia) showed high level of similarity among them and they were strongly associated with the wild susceptible genotype S. macrocarpum. Two cultivable genotypes Utkal Anushree and Utkal Madhuri could be utilized in future breeding programme and two wild genotypes S. torvum and S. sisymbriifolium could be used as resistant rootstocks in brinjal grafting.

In silico design and validation of a highly degenerate primer pair: a systematic approach

Background The techniques of amplifying genetic materials have enabled the extensive study of several biological activities outside the biological milieu of living systems. More recently, this approach has been extended to amplify population of genes, from evolutionarily related gene family for detection and evaluation of microbial consortial with several unique potentialities (e.g., enzymatic degradability). Conceivably, primer mixtures containing substitutions of different bases at specific sites (degenerate primers) have enabled the amplification of these genes in PCR reaction. However, the degenerate primer design problem (DPD) is a constraint to designing this kind of primer. To date, different algorithms now exist to solve various versions of DPD problem, many of which, only few addresses and satisfy the criteria to design primers that can extensively cover high through-put sequences while striking the balance between specificity and efficiency. The highly degenerate primer (HYDEN) design software program primarily addresses this variant of DPD problem termed “maximum coverage-degenerate primer design (MC-DPD)” and its heuristics have been substantiated for optimal efficiency from significant successes in PCR. In spite of the premium presented for designing degenerate primers, literature search has indicated relatively little use of its heuristics. This has been thought to result from the complexity of the program since it is run only by command-line, hence limiting its accessibility. To solve this problem, researchers have optionally considered the manual design of degenerate primers or design through software programs that provides accessibility through a graphical user interface (GUI). Realizing this, we have attempted in this study to provide a user-friendly approach for researchers with little or no background in bioinformatics to design degenerate primers using HYDEN Results Virtual Tests of our designed degenerate primer pair through in silico PCR substantiated the correspondence between efficiency and coverage with the target sequences as pre-defined by the initial HYDEN output, thereby validating the potentials of HYDEN to effectively solve the MC-DPD problem. Additionally, the designed primer-pair mechanistically amplified all sequences used as a positive control with no amplification observed in the negative controls. Conclusion In this study, we provided a turnkey protocol to simplify the design of degenerate primers using the heuristics of the HYDEN software program.

ARDEP, a Rapid Degenerate Primer Design Pipeline Based on k-mers for Amplicon Microbiome Studies

The survey of microbial diversity in various environments has relied upon the widespread use of well-evaluated amplification primers for taxonomic marker genes (e.g., prokaryotic 16S and fungal ITS). However, it is urgent to develop a fast and accurate bioinformatic program to design primers for microbial functional genes to explore more mechanisms in the microbial community. Here, we provide a rapid degenerate primer design pipeline (ARDEP) based on the k-mer algorithm, which can bypass the time-consuming step of sequence alignment to greatly reduce run times while ensuring accuracy. In addition, we developed an open-access platform for the implementation of primer design projects that could also calculate the amplification product length, GC content, Annealing Temperature (Tm), and ΔG of primer self-folding, and identify covered species and functional groups. Using this new platform, we designed primers for several functional genes in the nitrogen cycle, including napA and amoA. Our newly designed primers achieved higher coverage than the commonly used primers for all tested genes. The program and the associated platform that applied the k-mer algorithm could greatly enhance the design and evaluation of primers for environmental microbiome studies.

ISOLASI FRAGMEN GEN PENYANDI PUTRESIN N-METILTRANSFERASE DAN QUINOLINAT FOSFORIBOSILTRANSFERASE ASAL TEMBAKAU LOKAL TEMANGGUNG (Nicotiana tabacum)

<p>ABSTRAK</p><p>Upaya untuk menurunkan kandungan nikotin merupakan salah satuprioritas utama penelitian tembakau. Nikotin adalah senyawa alkaloidutama berpotensi dikonversi menjadi senyawa nor-nikotin yang bersifatkarsinogen. Gen PMT sebagai penyandi enzim putresin n-metiltransferase(PMT) dan gen QPT - penyandi enzim quinolinat fosforibosiltransferase(QPT) merupakan dua gen kunci yang berperan penting pada proses bio-sintesis nikotin. Penelitian ini bertujuan untuk mengisolasi potongan genPMT dan QPT asal tembakau lokal Indonesia, mengkarakterisasi danmenganalisis runutan DNA-nya. Tahapan penelitian dimulai dengan me-rancang primer degenerate berdasarkan informasi yang ada di pangkalandata Bank Gen NCBI (National Centre for Biotechnology Information),mengamplifikasi PCR menggunakan templat DNA genomik tembakaulokal cv. Sindoro1, mengklon potongan DNA hasil PCR dan menentukanrunutan DNA-nya. Hasil penelitian menunjukkan dari dua belas pasangprimer degenerate yang dirancang, hanya dua pasang primer yang meng-hasilkan potongan DNA hasil amplifikasi PCR, yaitu pasangan primerPMt-7 (F &amp; R) untuk gen PMT dan primer QPt-3 (F &amp; R) untuk gen QPT.Setelah dilakukan penentuan runutan DNA-nya, amplikon yang didapatdari hasil PCR dengan pasangan primer PMt-7 sebesar 1418 bp, sedangkanuntuk primer QPt-3 sebesar 205 bp. Runutan DNA gen PMT dan gen QPTasal tembakau lokal cv. Sindoro1 mempunyai tingkat kesamaan yang ting-gi dengan gen PMT dan gen QPT asal tembakau lainnya yang ada dipangkalan data Bank Gen NCBI.</p><p>Kata kunci : Gen PMT, gen QPT, lintasan biosintesis nikotin, perunutanDNA, amplifikasi PCR, primer degenerate</p><p>ABSTRACT</p><p>Isolation of Genes encoding Putrescine N-Methyl-transferase and Quinolinat Phosphoribosyl transferasederived from Temanggung Tobacco Cultivar (Nicotianatabacum)</p><p>Reduction of nicotine content is one of the major objective intobacco research. Nicotine is the main alcaloid compound that potentiallycould be converted into a carcinogenic compound (nor-nicotine). The PMTgene encoding putrescine N-methyl transferase (PMT) and the QPT gene -encoding quinolinate phosphoribosyl transferase (QPT) are the two keyenzymes involved in nicotine biosynthesis. The objectives of this researchwere to isolate PMT and QPT gene fragments originated from Indonesianlocal tobacco, to characterize, and to analyze their DNA sequences. Theresearch activities included: degenerate primer design based oninformation available in the GenBank DNA Database NCBI (NationalCentre for Biotechnology Information), PCR amplification usingdegenerate primer and genomic DNA template of a local tobacco cv.Sindoro1, clone the PCR amplified products, and determine their DNAnucleotide sequences. Results of the experiment indicated that from 12degenerate primer pairs synthesized, only two were able to yield positivePCR amplified products. These primer pairs were PMt-7 (F &amp; R primers)for PMT and QPt-3 (F &amp; R primers) for QPT. After DNA sequencing, theamplified DNA product amplified using PMt-7 degenerate primer pairswere 1418 bp, while that using QPt-3 primer pairs were only 205 bp.Nucleotide sequences of PMT or QPT gene fragments originated fromlocal tobacco cv. Sindoro1 showed a high nucleotide sequences identity ascompared to that of the respective genes from other tobacco species thatwere available in the GenBank DNA Database NCBI.</p><p>Key words: PMT gene, QPT gene, nicotine biosynthetic pathways, DNAsequencing, PCR amplification, degenerate primer</p>

An Optimized Metabarcoding Method for Mimiviridae

Mimiviridae is a group of viruses with large genomes and virions. Ecological relevance of Mimiviridae in marine environments has been increasingly recognized through the discoveries of novel isolates and metagenomic studies. To facilitate ecological profiling of Mimiviridae, we previously proposed a meta-barcoding approach based on 82 degenerate primer pairs (i.e., MEGAPRIMER) targeting the DNA polymerase gene of Mimiviridae. The method detected a larger number of operational taxonomic units (OTUs) in environmental samples than previous methods. However, it required large quantities of DNA and was laborious due to the use of individual primer pairs. Here, we examined coastal seawater samples using varying PCR conditions and purification protocols to streamline the MEGAPRIMER method. Mixing primer pairs in “cocktails” reduced the required amount of environmental DNA by 90%, while reproducing the results obtained by the original protocol. We compared the results obtained by the meta-barcoding approach with quantifications using qPCR for selected OTUs. This revealed possible amplification biases among different OTUs, but the frequency profiles for individual OTUs across multiple samples were similar to those obtained by qPCR. We anticipate that the newly developed MEGAPRIMER protocols will be useful for ecological investigation of Mimiviridae in a larger set of environmental samples.