Cloning and characterization of a highly repeated DNA sequence in Hordeum vulgare L.

Genome ◽  
1996 ◽  
Vol 39 (6) ◽  
pp. 1159-1168 ◽  
Author(s):  
Kebin Liu ◽  
Shauna Somerville

A novel repetitive DNA sequence, R10hvcop, has been identified in the barley (Hordeum vulgare L.) genome. This 830 base pair (bp) DNA sequence has a 606-bp open reading frame and is present as approximately 1.96 × 105 copies per haploid barley genome. Southern blot analysis revealed that repetitive DNA elements containing R10hvcop and related sequences were dispersed within the barley chromosomes. Sequences similar to R10hvcop were also found in wheat (Triticum aestivum L.), rye (Secale cereale L.), and oat (Avena sativa L.) with copy numbers of 8 × 104, 1.39 × 105, and 7.9 × 104 per haploid genome, respectively. Sequences similar to R10hvcop were also present in the corn (Zea mays L. ssp. mays) genome, but they were not highly repeated. Barley, wheat, rye, oat, and corn showed species-specific restriction fragment length polymorphisms of R10hvcop and related sequences. Computer-based similarity searches revealed that R10hvcop is closely related to reverse transcriptase genes in retrotransposons and retrotransposon-like elements of several plant species and of Drosophila. The highly repetitive nature, interspersed distribution, and high degree of similarity to reverse transcriptase genes suggests that R10hvcop contains the sequence of a diverged reverse transcriptase gene. Key words : repetitive DNA, barley, reverse transcriptase gene, sequence divergence.

Genome ◽  
1996 ◽  
Vol 39 (1) ◽  
pp. 9-16
Author(s):  
X. Xia ◽  
S. Du ◽  
L. Erickson

Based on DNA sequence analysis of 5 clones of repetitive DNA from alfalfa (Medicago sativa), we propose the existence of a dispersed middle repetitive element about 3400 bp long with a copy number in the range of 2–3 × 103 per haploid genome. The average A + T content of the sequences was 54.6%, compared with 61.4% for the alfalfa genome. Sequence homologies between overlapping regions of the clones ranged from 85 to 89.5% with an average of 86.6%; sequence divergence was due largely to single base pair changes, with deletions or insertions occurring randomly across sequences. An open reading frame (ORF) in one clone, RPE15, contained homologies to cereal prolamin genes and a legumin box was located upstream of the coding region. A Northern blot of RNA from various alfalfa tissues, probed with the above clone containing this ORF, showed an extensive heterodispersed pattern of hybridization in the late stages of flower bud development but in no other tissues. Key words : lucerne, Medicago sativa, repetitive DNA, plant genomes.


Author(s):  
ANDERSON LUIZ NUNES ◽  
RIBAS ANTONIO VIDAL

A determinação da concentração de compostos no solo por meio de plantas quantificadoras apresenta como principal vantagem detectar somente resíduos biologicamente ativos, não havendo necessidade de instrumentos onerosos e de prévia extração dos resíduos do solo. Dessa forma, este trabalho teve como objetivo selecionar plantas quantificadoras da presença de herbicidas residuais (pré emergentes) para o uso em bioensaios. Utilizou-se delineamento experimental completamente casualizado com arranjo bifatorial 8 x 6, com cinco repetições. O fator A consistiu de espécies cultiváveis e o fator B de herbicidas aplicados em pré emergência. Os resultados evidenciaram que a sensibilidade na detecção do herbicida no solo depende da espécie utilizada. A sensibilidade das espécies Lactuca sativa L. e Raphanus sativus var. sativus L. não permitiu condições de quantificar a presença dos herbicidas atrazina, cloransulam, imazaquin, metribuzin e S-metolacloro. Raphanus sativus var. oleiferus Metzger é potencial quantificador de imazaquin e S metolacloro. Plantas de Curcubita pepo L. são promissoras na bioavaliação de metribuzin. A espécie Cucumis sativus L. mostrou-se potencial bioindicadora de cloransulan e imazaquin. Avena sativa L. apresentou-se como potencial quantificadora de imazaquin e metribuzin. Hordeum vulgare L. pode quantificar o metribuzin e Triticum aestivum L. é promissor na detecção da biodisponibilidade de atrazina.


1978 ◽  
Vol 58 (1) ◽  
pp. 241-248 ◽  
Author(s):  
J. WADDINGTON

Under greenhouse conditions, incorporating ground straw in the soil at rates between 2,240 and 8,970 kg/ha reduced the emergence of alfalfa (Medicago media Pers. cv. Beaver) significantly (P < 0.05) and bromegrass (Bromus inermis Leyss cv. Magna) slightly, but had no effect on barley (Hordeum vulgare L. cv. Conquest). Rape (Brassica napus L. cv. Target and B. campestris L. cv. Echo) straws were more damaging than wheat (Triticum aestivum L. cv. Manitou) straw. Symptoms of severe nitrogen deficiency appeared early in the growth of barley where straw had been added to the soil. The effect on tillering varied. In one experiment tillers were smaller, in one tillers were larger; but in both, total leaf area produced was much less where 8,970 kg/ha of straw had been added to the soil. Bromegrass showed the same effects but to a lesser degree, probably because of slower growth requiring a smaller supply of nitrogen. Alfalfa growth was apparently unaffected. There was no evidence that the straw of either rapeseed species was more deleterious than wheat straw to crop growth after emergence. It is concluded that straw incorporated in soil affected barley and bromegrass growth by reducing the availability of nitrogen.


Genome ◽  
2001 ◽  
Vol 44 (4) ◽  
pp. 523-528 ◽  
Author(s):  
Raja Kota ◽  
Markus Wolf ◽  
Wolfgang Michalek ◽  
Andreas Graner

Recent advances in DNA sequence analysis and the establishment of high-throughput assays have provided the framework for large-scale discovery and analysis of DNA sequence variation. In this context, single nucleotide polymorphisms (SNPs) are of particular interest. To initiate a systematic approach to develop an SNP map of barley (Hordeum vulgare L.), we have employed denaturing high-performance liquid chromatography (DHPLC) to analyse segregating SNP patterns in a doubled-haploid (DH) mapping population. To this end, SNPs between the parental genotypes were identified using a direct sequencing approach. Once a SNP was established between the parents, the optimal melting temperature of the PCR fragment containing the SNP was predicted for its analysis by DHPLC. Following the detection of the optimal temperature, the DH lines were analysed for the presence of either of the alleles. To test the utility of the analysis, data from previously mapped RFLP markers from which these SNPs were derived were compared. Results from these experiments indicate that DHPLC can be efficiently employed in analysing SNPs on a high-throughput scale.Key words: denaturing high performance liquid chromatography, doubled-haploid lines, restriction fragment length polymorphism, genetic mapping, molecular markers.


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