Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.6.1.1 (aspartate aminotransferase)
 21,665 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Legumes obtain a substantial portion of their nitrogen (N) from symbiotic N2 fixation in root nodules. The glutamine synthetase (GS, EC 6.3.1.2)/glutamate synthase (GOGAT) cycle is responsible for the initial N assimilation. This report describes the analysis of a transgenic alfalfa (Medicago sativa L.) line containing an antisense NADH-GOGAT (EC 1.4.1.14) under the control of the nodule-enhanced aspartate amino-transferase (AAT-2) promoter. In one transgenic line, NADH-GOGAT enzyme activity was reduced to approximately 50%, with a corresponding reduction in protein and mRNA. The transcript abundance for cytosolic GS, ferredoxin-dependent GOGAT (EC 1.4.7.1), AAT-2 (EC 2.6.1.1), asparagine synthase (EC 6.3.5.4), and phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31) were unaffected, as were enzyme activities for AAT, PEPC and GS. Antisense NADH-GOGAT plants grown under symbiotic conditions were moderately chlorotic and reduced in growth and N content, even though symbiotic N2 fixation was not significantly reduced. The addition of nitrate relieved the chlorosis and restored growth and N content. Surprisingly, the antisense NADH-GOGAT plants were male sterile resulting from inviable pollen. A reduction in NADH-GOGAT enzyme activity and transcript abundance in the antisense plants was measured during the early stages of flower development. Inheritance of the transgene was stable and resulted in progeny with a range of NADH-GOGAT activity. These data indicate that NADH-GOGAT plays a critical role in the assimilation of symbiotically fixed N and during pollen development.
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PMID:Decreased NADH glutamate synthase activity in nodules and flowers of alfalfa (Medicago sativa L.) transformed with an antisense glutamate synthase transgene. 1093 93

Dahlia (Dahlia variabilis Hort.) is a significant ornamental plant in New Zealand. Symptoms such as mosaic, ring spots, mottling, and veinal chlorosis, suggestive of a viral infection, are often seen in various dahlia collections. To better understand the incidence of viruses in dahlia in New Zealand, several popularly grown cultivars were evaluated for viruses that are known to infect dahlia. Viruses that were tested included Cucumber mosaic virus (CMV), Dahlia mosaic virus (DMV), Impatiens necrotic spot virus (INSV), Tobacco streak virus (TSV), and Tomato spotted wilt virus (TSWV). At least one symptomatic plant was tested from each of the following cultivars: Akito Dawn, Cincinnati Dancer, Hamari Accord, Hamari Rose, LeBatts Prime, LeVonne Splinter, Riverlea Tropicana, Spartacus, Tartan, Tui Connie, and Wandas Antartica. Except for DMV, initial testing was done by ELISA with commercially available kits for the above viruses. In the case of dahlia mosaic, samples were tested for DMV that was described previously (4) and two additional and distinct caulimoviruses (DMV-D10 and DMV-Holland) that were found to be associated with dahlia (1,2). Primer pairs, ORF6st: ATG GAA GAA ATT AAG GCG T and ORF6end: TTG TCT TCA TCC ATA AAG CAG; DenF1: CAG CAA GAA ACA GGA ATT GA and DenR: TTA CAG TCG AAG CTG CTA AA; and Kapht-F: ATG AGT AAT GCT TCA GCA A and Kapht-R: TGA CCA TGG CTT CTA ACT GT were used for the specific detection of DMV-D10, DMV-Holland, and DMV, respectively (1). None of the samples tested were ELISA positive for CMV, INSV, or TSWV. To verify the TSV infection, TSV-specific primers (5'-GTC CAG ACC ATC CAT CCA AC-3' and 5'-TTG ATT CAC CAG GAA ATC TT-3'), designed based on sequences available in GenBank, were used in reverse transcription (RT)-PCR. For DMV, the diagnostic tests used were electron microscopy and PCR followed by amplicon cloning and sequencing. Electron microscopic observation of leaf-dip preparations showed near isometric virions, approximately 50 to 60 nm in all samples tested. PCR showed that all samples tested were positive for DMV-Holland and DMV-D10. While DMV-Holland is a typical caulimovirus, DMV-D10 was found to exist as an endogenous plant pararetroviral sequence in dahlia (3). One sample each from two cultivars, Spartacus and Tui Connie, were positive for TSV by ELISA, RT-PCR, followed by the sequence analysis of the cloned amplicon. The impact of TSV-infected dahlias as a potential source of inoculum remains to be seen. Our results suggested the prevalence of dahlia mosaic-associated caulimoviruses in several dahlia cultivars and the presence of TSV in New Zealand dahlias. Dahlia mosaic continues to be prevalent in several parts of the world (1), and with the current findings in New Zealand, testing for these viruses should be conducted to ensure virus-free status of the propagating material. References: (1) V. Pahalawatta et al. Plant Dis. 91:1194, 2007. (2) V. Pahalawatta et al. Arch. Virol.153:733, 2008. (3) V. Pahalawatta et al. Virology 376:253, 2008. (4) R. D. Richins and R. J. Shepherd. Virology 124:208, 1983.
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PMID:Dahlia mosaic virus and Tobacco streak virus in Dahlia (Dahlia variabilis) in New Zealand. 3076 5

Stunting, chlorosis, and light yellow mottling resembling symptoms of nutrient deficiency were observed in angelonia (Angelonia angustifolia) in commercial production in New York. Numerous, filamentous particles 520 to 540 nm long and spherical virus particles 30 nm in diameter were observed by transmission electron microscopy (TEM) in negatively stained partially purified extracts of symptomatic Angelonia leaf tissue. Two viruses, the filamentous potexvirus Alternanthera mosaic virus (AltMV) and the spherical carmovirus Angelonia flower break virus (AnFBV) were subsequently identified on the basis of nucleotide sequence analysis of amplicons generated by reverse transcription (RT)-PCR using total RNA isolated from infected leaf tissue. A 584-bp portion of the replicase-encoding region of the AltMV genome was obtained with the degenerate primers Potex 2RC (5'-AGC ATR GNN SCR TCY TG-3') and Potex 5 (5'-CAY CAR CAR GCM AAR GAT GA-3') (3). Forward (AnFBV CP 1F-5'-AGC CTG GCA ATC TGC GTA CTG ATA-3') and reverse (AnFBV CP 1R-5'-AAT ACC GCC CTC CTG TTT GGA AGT-3') primers based on the published AnFBV genomic sequence (GenBank Accession No. NC_007733) were used to amplify a portion of the viral coat protein (CP) gene. The nucleotide sequence of the amplicon generated using the potexvirus-specific primers (GenBank Accession No. EU679362) was 99% identical to the published AltMV (GenBank Accession No. NC_007731) sequence and the nucleotide sequence of the amplicon obtained using the AnFBV CP primers was 99% identical to the published AnFBV genomic sequence (GenBank Accession No. EU679363). AnFBV occurs widely in angelonia (1) and AltMV has been identified in phlox (2). These data confirm the presence of AltMV and AnFBV in diseased angelonia plants showing stunting and nutrient deficiency-like symptoms and substantiates, to our knowledge, this first report of AltMV in angelonia in the United States. References: (1) S. Adkins et al. Phytopathology 96:460, 2006. (2) J. Hammond et al. Arch. Virol. 151:477, 2006. (3) R. A. A. van der Vlugt and M. Berendeson. Eur. J. Plant Pathol. 108:367, 2002.
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PMID:First Report of Alternanthera mosaic virus Infection in Angelonia in the United States. 3076 47