Assessment of somaclonal variation for salinity tolerance in sweet potato regenerated plants

Genetic variation is the source for plant breeding. Somaclonal variation is genetic variation induced during tissue culture and also during ordinary growth in vivo, and occurs rather, often in sweet potato. The aim of the present study was to evaluate the degree of somaclonal variation in regeneration via somatic embryogenesis by phenotypic analysis under salinity stress condition and to assess the potential of somaclonal variation for development of salinity tolerant cultivar in sweet potato. The regenerated and control plants were evaluated under an established in vitro salinity screen system where media were supplemented with 0, 75, 150 and 200 mM of NaCl. The data for parameters (number of roots, length of roots, leaf and root condition) was recorded in three repeat tests. Data analysis suggested a significant variation in salinity tolerance among regenerated and control plants that proved the occurrence of somaclonal variation in regenerated plants. Despite none of the regenerated line was selected as a salt tolerant line, present study shows that regenerated plants exhibited somaclonal variation that can be utilized for selection of desired traits in sweet potato.Key words: Sweet potato, regeneration, somaclonal variation, salinity tolerance

Bio-informatic analysis of a vacuolar Na+/H+ antiporter (AlaNHX) from the salt resistant grass Aeluropus lagopoides

Sodium-hydrogen antiporter (NHX) protein regulates the trans-membrane transport of Na+ in higher plants. Vacuolar- NHX is a type of NHX protein located on tonoplast and minimizes the accumulation of Na+ in cytoplasm by compartmentalizing into vacuole especially in salt tolerant plants. In Aeluropus lagopoides, AlaNHX [NCBI: GU199336, Vacuolar-NHX] plays a vital role for efficient Na+ sequestration into the vacuole and helps in plant survival in saline areas. Therefore, sequence analysis, structural analysis and modeling of AlaNHX were performed through bioinformatics tools. Homology of AlaNHX was 99% similar with the Na+/H+ antiporter of Aeluropus littoralis. Sequence of AlaNHX consisted of 2353 bp including 337 bp of un-translated regions (UTR) at 5΄ and 393 at 3΄ end. In addition, AlaNHX have an “open reading frame” (ORF) of 1623 bp which translated into 59.4 KDa protein containing 540 amino acids (Leucine+ Serine contributed in 22% of peptide chain). AlaNHX protein consists of 10 transmembrane domains (TMD; 3 primary and 7 secondary protein structural type) and a long (95 amino acids) carboxyl terminal end in cytoplasmic region. In addition, 3, 5, 7 and 8 TMD regions of AlaNHX were highly conserved. Different glycosylation, phosphorylation and myristoylation sites were also found in AlaNHX protein. Three-dimensional (3D) structure analysis revealed that this protein may be classified as stable and of hydrophobic nature containing a significant proportion of alpha helices. In this study, a three-dimensional structure of AlaNHX protein was predicted by using in-silico3D homology modeling technique. This study provides baseline information for understanding the importance of NHX protein structure in salinity resistance of grasses. This information could help in improving salinity tolerance in salt sensitive grasses through genetic engineering.Scopu

Genetic structure of landraces in foxtail millet (Setaria italica (L.) P. Beauv.) revealed with transposon display and interpretation to crop evolution of foxtail millet

Although the origin and domestication process of foxtail millet (Setaria italica subsp. italica (L.) P. Beauv.) has been studied by several groups, the issue is still ambiguous. It is essential to resolve this issue by studying a large number of accessions with sufficient markers covering the entire genome. Genetic structures were analyzed by transposon display (TD) using 425 accessions of foxtail millet and 12 of the wild ancestor green foxtail (Setaria italica subsp. viridis (L.) P. Beauv.). We used three recently active transposons (TSI-1, TSI-7, and TSI-10) as genome-wide markers and succeeded in demonstrating geographical structures of the foxtail millet. A neighbor-joining dendrogram based on TD grouped the foxtail millet accessions into eight major clusters, each of which consisted of accessions collected from adjacent geographical areas. Eleven out of 12 green foxtail accessions were grouped separately from the clusters of foxtail millet. These results indicated strong regional differentiations and a long history of cultivation in each region. Furthermore, we discuss the relationship between foxtail millet and green foxtail and suggest a monophyletic origin of foxtail millet domestication

Construction of Integrated Genetic Map between Various Existing DNA Markers and Newly Developed P450-related PBA Markers in Diploid Potato (Solanum tuberosum)

We have generated estimates of the genomic distribution of newly developed molecular markers, which are P450-based analogues (PBAs), in diploid potato (Solanum tuberosum, 2n=2x=24) based on functional genomics. A total of 401 markers, including 111 SSR, 33 RFLP, 87 RFLP-STS, 45 CAPS, 94 RAPD, 15 PBA, 9 AFLP, 3 RGL and 4 ISSR markers, were employed in a parental polymorphism survey. A total of 127 out of 401 markers (172 loci) displayed polymorphisms between parents and were confirmed to show segregation in partial progenies. These selected 127 markers were then tested for their possible use for a whole mapping population. The subsequent results of genetic mapping of the PBAs revealed that they were distributed on at least 8 chromosomes, suggesting that they have a significant potential not only as tools for assessing genetic diversity but also as effective markers to construct more detailed genetic maps of potato, in conjunction with existing identified genetic loci. To integrate the information from existing maps into our mapping study, we performed a comparative analysis between two representative maps (RFLP and SSR-based) with our PBA map. Based on the subsequent results, we predict that our map will be useful as a bridge between the existing genetic maps of potato and will enable to integrate information about different markers

Genetic diversity and population structure of ‘Khao Kai Noi’, a Lao rice (Oryza sativa L.) landrace, revealed by microsatellite DNA markers

Rice (Oryza sativa L.) is the main food for people in Laos, where it has been grown and eaten since prehistory. Diverse landraces are grown in Laos. ‘Khao Kai Noi’, a landrace favored for its eating quality, is held in the nationwide collection of traditional landraces in the Lao national genebank. Genetic diversity is crucial for sustainable use of genetic resources and conservation. To investigate the genetic diversity of ‘Khao Kai Noi’ for conservation, we genotyped 70 accessions by using 23 polymorphic simple sequence repeat markers. The markers generated 2 to 17 alleles (132 in total), with an average of 5.7 per locus. The total expected heterozygosity over all ‘Khao Kai Noi’ accessions was 0.271. Genetic variation was largest among accessions and smallest within accessions. Khao Kai Noi accessions were classified into three different genetic backgrounds, but there was unclear association between the three inferred population and name subgroups and geographical distribution. Most of the accessions were clustered with temperate japonica and showed genetic relatedness to rice from neighboring provinces of Vietnam, suggesting a Vietnamese origin. The results of this study will contribute to the conservation, core collection and future breeding of the Khao Kai Noi population

Use of Rice SSR Markers as RAPD Markers for Genetic Diversity Analysis in Zingiberaceae

Species of Zingiberaceae display a diversity in habitat, ethnobotanical use and morphology. However, little is known about the genetic relationships among taxa and genetic diversity, primarily due to the lack of suitable molecular markers. We tested the cross-amplification potential of microsatellite markers among taxa to identify a larger number of genetic markers. To assess the applicability of rice microsatellite markers to the Zingiberaceae, we tested 12 microsatellite markers for 14 genotypes from three genera of this family: Zingiber, Alpinia and Curcuma. The origin of the genotypes was diverse, covering eight Asian countries. Four microsatellite primer sets failed to amplify fragments in all genotypes studied, whereas the other primer sets amplified all the genotypes. Among the 141 bands, that could be scored, 140 (99.5%) were polymorphic. On the average, each microsatellite primer set amplified 17.6 DNA fragments. In general, amplified fragments were larger than the original rice fragments including the microsatellite region, although in some cases, the amplified bands were similar in size. Though sequence analysis of these bands confirmed the absence of target repeat motif, amplification of a large number of polymorphic bands provided the basis to perform an analysis of genetic diversity. Primers could generate enough polymorphism for possible use in diversity studies, based on provisional multivariate analyses such as cluster analysis and principal component analysis (PCA). The whole set of genotypes based on molecular data was classified into four clusters after cluster analysis. Genotypes from the Curcuma and Alpinia genera were grouped into clusters I and II, respectively. Clusters III and IV comprised genotypes from the genus Zingiber. PCA led to a similar classification. The high polymorphism documented in the present study indicated that the rice microsatellite primers were useful for genetic diversity studies among genera in the family Zingiberaceae

Erratum: Evaluation of the yield of abiotic-stress-tolerant <i>AtDREB1A</i> transgenic potato under saline conditions in advance of field trials

Original Article : Breeding Science 66: 703–710 (2016)https://doi.org/10.1270/jsbbs.1605

The Suzaku Observation of the Nucleus of the Radio-Loud Active Galaxy Centaurus A: Constraints on Abundances of the Accreting Material

A Suzaku observation of the nucleus of the radio-loud AGN Centaurus A in 2005 has yielded a broadband spectrum spanning 0.3 to 250 keV. The net exposure times after screening were: 70 ks per X-ray Imaging Spectrometer (XIS) camera, 60.8 ks for the Hard X-ray Detector (HXD) PIN, and 17.1 ks for the HXD-GSO. The hard X-rays are fit by two power-laws of the same slope, absorbed by columns of 1.5 and 7 * 10^{23} cm^{-2} respectively. The spectrum is consistent with previous suggestions that the power-law components are X-ray emission from the sub-pc VLBI jet and from Bondi accretion at the core, but it is also consistent with a partial covering interpretation. The soft band is dominated by thermal emission from the diffuse plasma and is fit well by a two-temperature VAPEC model, plus a third power-law component to account for scattered nuclear emission, jet emission, and emission from X-ray Binaries and other point sources. Narrow fluorescent emission lines from Fe, Si, S, Ar, Ca and Ni are detected. The Fe K alpha line width yields a 200 light-day lower limit on the distance from the black hole to the line-emitting gas. Fe, Ca, and S K-shell absorption edges are detected. Elemental abundances are constrained via absorption edge depths and strengths of the fluorescent and diffuse plasma emission lines. The high metallicity ([Fe/H]=+0.1) of the circumnuclear material suggests that it could not have originated in the relatively metal-poor outer halo unless enrichment by local star formation has occurred. Relative abundances are consistent with enrichment from Type II and Ia supernovae.Comment: Accepted for publication to ApJ. 22 pages, 11 figures (3 color). Uses emulateapj5.sty. Grammatical errors corrected; some references update

Effect of starting materials on the superconducting properties of SmFeAsO1-xFx tapes

SmFeAsO1-xFx tapes were prepared using three kinds of starting materials. It shows that the starting materials have an obvious effect on the impurity phases in final superconducting tapes. Compared with the other samples, the samples fabricated by SmAs, FeO, Fe2As, and SmF3 have the smallest arsenide impurity phase and voids. As a result, these samples possess much denser structure and better grain connectivity. Moreover, among the three kinds of samples fabricated in this work, this kind of sample has the highest zero-resistivity temperature ~40 K and largest critical current density ~4600 A/cm^2 in self-field at 4.2 K. This is the highest Jc values reported so far for SmFeAsO1-xFx wires and tapes.Comment: 15 pages, 4 figure

Development of a Multi-Step Leukemogenesis Model of MLL-Rearranged Leukemia Using Humanized Mice

Mixed-lineage-leukemia (MLL) fusion oncogenes are intimately involved in acute leukemia and secondary therapy-related acute leukemia. To understand MLL-rearranged leukemia, several murine models for this disease have been established. However, the mouse leukemia derived from mouse hematopoietic stem cells (HSCs) may not be fully comparable with human leukemia. Here we developed a humanized mouse model for human leukemia by transplanting human cord blood-derived HSCs transduced with an MLL-AF10 oncogene into a supra-immunodeficient mouse strain, NOD/Shi-scid, IL-2Rγ−/− (NOG) mice. Injection of the MLL-AF10-transduced HSCs into the liver of NOG mice enhanced multilineage hematopoiesis, but did not induce leukemia. Because active mutations in ras genes are often found in MLL-related leukemia, we next transduced the gene for a constitutively active form of K-ras along with the MLL-AF10 oncogene. Eight weeks after transplantation, all the recipient mice had developed acute monoblastic leukemia (the M5 phenotype in French-American-British classification). We thus successfully established a human MLL-rearranged leukemia that was derived in vivo from human HSCs. In addition, since the enforced expression of the mutant K-ras alone was insufficient to induce leukemia, the present model may also be a useful experimental platform for the multi-step leukemogenesis model of human leukemia