The khmer software package: enabling efficient nucleotide sequence analysis [version 1; referees: 2 approved, 1 approved with reservations]

The khmer package is a freely available software library for working efficiently with fixed length DNA words, or k-mers. khmer provides implementations of a probabilistic k-mer counting data structure, a compressible De Bruijn graph representation, De Bruijn graph partitioning, and digital normalization. khmer is implemented in C++ and Python, and is freely available under the BSD license at https://github.com/dib-lab/khmer/

RNA editing in chloroplast NADH dehydrogenase (ndhA) of salt stressed wild barley revealed novel type G to A

The ndhA gene of NAD(P)H dehydrogenase in chloroplast DNA is vital for the electron transport chain and needs to be studied, especially in the context of RNA editing and its effects. Wild barley (Hordeum vulgare subsp. spontaneum) plants were studied in 4 groups, with exposure to 500 mM NaCl for 0 h – control (accession no. OM262848), and three treatment groups: 2 h (accession no. OM262849), 12 h (accession no. OM262850) and 24 h (accession no. OM262851) and their RNA was sent for RNA-seq sequencing. The sequences were submitted to NCBI SRA archives and analyzed together after filtering for high quality. This was done to show the RNA editing position and percentages at 10 sites across the ndhA gene. The RNA edits were validated using quantitative-PCR and homology models for the ndhA protein after exposure to salt stress were also generated. The four treatments showed five C to U changes (C50, C303, C563, C1042, C1047), three U to C changes (U550, U592, U1066), and two G to A changes (G111, G1046). We investigated the extent and effect of RNA editing in ndhA transcripts from chloroplasts of barley. We observed high RNA editing percentages after the second hour of salt stress.We have also observed for the first time about ‘U to C’ RNA edits in ndhA gene of wild barley

Developing transgenic wheat to encounter rusts and powdery mildew by overexpressing barley chi26 gene for fungal resistance

Abstract Background The main aim of this study was to improve fungal resistance in bread wheat via transgenesis. Transgenic wheat plants harboring barley chitinase (chi26) gene, driven by maize ubi promoter, were obtained using biolistic bombardment, whereas the herbicide resistance gene, bar, driven by the CaMV 35S promoter was used as a selectable marker. Results Molecular analysis confirmed the integration, copy number, and the level of expression of the chi26 gene in four independent transgenic events. Chitinase enzyme activity was detected using a standard enzymatic assay. The expression levels of chi26 gene in the different transgenic lines, compared to their respective controls, were determined using qRT-PCR. The transgene was silenced in some transgenic families across generations. Gene silencing in the present study seemed to be random and irreversible. The homozygous transgenic plants of T4, T5, T6, T8, and T9 generations were tested in the field for five growing seasons to evaluate their resistance against rusts and powdery mildew. The results indicated high chitinase activity at T0 and high transgene expression levels in few transgenic families. This resulted in high resistance against wheat rusts and powdery mildew under field conditions. It was indicated by proximate and chemical analyses that one of the transgenic families and the non-transgenic line were substantially equivalent. Conclusion Transgenic wheat with barley chi26 was found to be resistant even after five generations under artificial fungal infection conditions. One transgenic line was proved to be substantially equivalent as compared to the non-transgenic control

The khmer software package: enabling efficient nucleotide sequence analysis [version 1; referees: 2 approved, 1 approved with reservations]

The khmer package is a freely available software library for working efficiently with fixed length DNA words, or k-mers. khmer provides implementations of a probabilistic k-mer counting data structure, a compressible De Bruijn graph representation, De Bruijn graph partitioning, and digital normalization. khmer is implemented in C++ and Python, and is freely available under the BSD license at https://github.com/dib-lab/khmer/