Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.6.1.44 (AGT)
 770 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The paradigm of involvement of LexA in regulation of only SOS-response in bacteria through the down-regulation of DNA repair genes was challenged in the unicellular cyanobacterium, Synechocystis PCC6803, wherein it was originally shown not to be associated with DNA repair and later also involved in management of carbon-starvation through up-regulation of C-metabolism genes. In the filamentous cyanobacterium, Anabaena sp. strain PCC7120, global stress management role for LexA and a consensus LexA-binding box (AnLexA-box) has been established using a LexA-overexpressing recombinant strain, AnlexA+. High levels of LexA rendered Anabaena cells sensitive to different DNA damage and oxidative stress-inducing agents, through the transcriptional down-regulation of the genes involved in DNA repair and alleviation of oxidative stress. LexA overexpression enhanced the ability of Anabaena to tolerate C-depletion, induced by inhibiting photosynthesis, by up-regulating genes involved in C-fixation and down-regulating those involved in C-breakdown, while maintaining the overall photosynthetic efficiency. A consensus LexA-binding box, AnLexA-box [AGT-N4-11-ACT] was identified upstream of both up- and down-regulated genes using a subset of Anabaena genes identified on the basis of proteomic analysis of AnlexA+ strain along with a few DNA repair genes. A short genome search revealed the presence of AnLexA box in at least 40 more genes, with functional roles in fatty acid biosynthesis, toxin-antitoxin systems in addition to DNA repair, oxidative stress, metal tolerance and C-metabolism. Thus, Anabaena LexA modulates the tolerance to multitude of stresses through transcriptional up/down-regulation of their functional genes directly by binding to the AnLexA Box present in their promoter region.
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PMID:Regulation of multiple abiotic stress tolerance by LexA in the cyanobacterium Anabaena sp. strain PCC7120. 3005 21

Viruses are a major biotic constraint on sweet potato (Ipomoea batatas (L.) Lam) production worldwide. In 2005, 10 to 60% viral disease incidence was observed in sweet potato fields. Symptoms include ring and chlorotic spots, puckering, feathering, vein clearing, and leaf curl with chlorotic specks and pink spots. Cuttings from symptomatic plants were collected from Kerala (two clones), Orrisa (eight clones), and Adrapradesh (three clones) and maintained in an insect-proof glasshouse. Leaves from symptomatic plants were mechanically inoculated to I setosa, I. nil, Nicotiana tabacum, N. benthamiana, Datura stramonium, and Chenapodium quinoa (12 seedlings each). Vein clearing, netting, and leaf distortion were observed in I. setosa and N tabacum 7 days postinoculation, chlorotic spots observed in N. benthamiana, and violet spots and violet margins on leaves observed on I. Nil. No symptoms were observed on D. stramonium and C. quinoa. When scions from the symptomatic sweet potato plants were graft inoculated onto I. setosa, vein clearing, leaf curl, and puckering-like symptoms were observed within 5 days. Mosaic and leaf curling symptoms were also observed on mechanically inoculated N. tabacum. Total nucleic acids isolated from the 33 field-collected sweet potato samples, graft inoculated I. setosa plants, and mechanically inoculated N. tabacum and I. nil plants were used for PCR and reverse transcription (RT)-PCR with geminivirus group specific (2) and potyvirus group specific primers (1). The expected 530-bp and 1.3-kb fragment were generated from the geminivirus and potyvirus primer sets, respectively. Potyvirus alone was detected in 7 of the 33 field-collected plants; geminivirus alone was detected in 7 other plants, while 19 plants contained detectible levels of potyvirus and geminivirus. To further identify the viruses, nested primers specific for the coat protein gene of Sweet potato feathery mottle virus (SPFMV) (CP1S 5'AGT GGG AAG GCA CCA TAC ATA GC 3', CP1A5' GCA GAG GAT GTC CTA TTG CAC ACC 3') (CP2S 5'TCT AGT GAA CGT ACT GAA TTC AAA GA 3', CP2A 5'ATT GCA CAC CCC TGA TTC CTA AGA 3') and Sweet potato leaf curl virus (SPLCV) (CP1- 5'ATG ACA GGG CGA ATT CGC GTT TC 3', CP2- 5'TTA ATT TTT GTG CGA ATC ATA 3') were designed. I. setosa and N. tabacum were amplified with SPFMV and SPLCV primers and the amplicons of 960 and 764 bp, respectively, obtained were subsequently cloned into pGEM-T Easy vector and sequenced. Nucleotide BLAST analysis revealed that the 960-bp fragment (GenBank Accession No. EF015398.) was 98% identical to two Egyptian isolates of SPFMV (Nos. AJ 515379 and AJ 515378). The nucleotide sequence of the 764-bp products (Nos. EF 151926 and EF15483) from the samples collected from Kerala and Orisa was 95% identical to each other. The sequence identity of EF 15483 with Sweet potato leaf curl Georgia virus (SPLCGV) isolate AF326775. was 91% and identity with China isolate DQ 512731 was 90% The isolate EF 151926 also was 91% identical to the SPLCGV with a high query and alignment score whereas identity with the China isolate was 91% with a low query coverage and alignment score. Phylogenic analysis with MEGA software program also showed the highest sequence similarity with SPLCGV, hence it is concluded that the geminivirus isolate under study is SPLCGV. To our knowledge, this is the first report of identification of SPFMV and SPLCGV occurring on sweet potato in India. Further study is required to understand the consequences of occurrence of these two viruses in India. References: (1) D. Colinet et al. Plant Dis. 28:223 1998. (2) D. D. Deng et al. Ann. Appl. Biol 125:327, 1993.
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PMID:Occurrence of Sweet potato feathery mottle virus and Sweet potato leaf curl Georgia virus on Sweet Potato in India. 3076 15

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

In the course of a survey to select superior old citrus lines in the area of Siracusa (Sicily, Italy), trees in several blocks of Fortune (Citrus reticulata Blanco), Nova (C. reticulata Blanco), Satsuma (C. unshiu (Macfad.) mandarins Marc.), and Marsh grapefruit (C. paradisi Macfad.) propagated on sour orange (C. aurantium L.) rootstock showed stunting, decline, dieback, and small-sized fruits. Stunting was particularly evident in grapefruit. Declined plants consistently showed pin-holing in the cambial face of sour orange bark below the bud union line, which is often associated with Citrus tristeza virus (CTV) infection. Young shoots from 600 Fortune, 300 Nova, 400 Satsuma, and 20 Marsh grapefruit plants showing decline were analyzed by double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) (Loewe Phytodiagnostica Biochemica, Sauerlach, Germany) and by immunoprinting-ELISA (Agritest Srl Valenzano-Bari-Italy) using CTV specific polyclonal antibodies. All decline tree samples reacted positively with both techniques while healthy greenhouse controls were negative. Total RNA was extracted from 50 of those plants, 25 Fortune and 15 Nova mandarins, 5 Satsuma, and 5 Marsh grapefruit (Qiagen RNeasy Plant minikit, Qiagen S.P.A., Milan, Italy), and tested in reverse transcription-polymerase chain reaction (RT-PCR) using specific primers for genes p20 (forward 5'-CGA GCT TAC TTT AGT GTT A-3' from CTV T36 genomic position 17767-17786 and reverse 5'-TAA TGT CAA ACT GAC CGC from CTV T36 position 18269-18286) and p23 (forward 5'-ACT AAC TTT AAT TCG AAC A-3' from CTV T36 position 18347-18286 and reverse 5'-AAC TTA TTC CGT CCA CTT C-3' from CTV T36 position 19026-19044) (2). In all cases, DNA fragments of the expected size were amplified. Equivalent samples from CTV-free greenhouse control plants did not react in ELISA and yielded no DNA after amplification with the same primers. When the history of the plants in the affected blocks was traced, it was found that all Fortune, Nova, satsuma and Marsh grapefruit trees had been propagated from budwood illegally imported from Spain 10 years before, suggesting the possibility that the imported buds were infected with CTV. The estimated number of infected plants in the area of Siracusa is approximately 10,000, and some evidence suggests that the virus might be spreading in the area (work in progress). Only scattered CTV-infected trees had been detected in Italy previously (1). To our knowledge, this is the first report of an important CTV outbreak in Italy. Additional surveys are being conducted to get a more accurate estimation of the CTV incidence, to determine if the virus is being dispersed by aphid vectors, and to biologically and molecularly characterize the virus strains present in the affected area. Presently, there are approximately 100,000 ha of citrus in Sicily, mostly grown on decline susceptible sour orange rootstock. The presence and potential spread of CTV is a major threat for this citrus industry. References: (1) M. Davino and G. Terranova. Frutticoltura 61:18, 1999. (2) A. Sambade et al. Plant Pathol. 51:257, 2002.
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PMID:The First Citrus tristeza virus Outbreak Found in a Relevant Citrus Producing Area of Sicily, Italy. 3081 70


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