ASSESSMENT OF THE RESISTANCE CONFERRED BY THE \u3ci\u3ebc-1\u3c/i\u3e ALLELES TO \u3ci\u3eBean common mosaic necrosis virus\u3c/i\u3e

INTRODUCTION: Bean common mosaic necrosis virus (BCMNV) is a potyvirus comprising several strains classified into two pathogroups according to the interactions with six recessive resistance alleles in common bean (1). These pathogroups (PGs), numbered III and VI, are defined by the ability (PG-VI) or inability (PG-III) of a BCMNV isolate to replicate in bean differential lines carrying bc-1 or bc-12 resistance alleles. The biological and molecular basis for this differential response of BCMNV isolates to the presence of bc-1 alleles is not known. Conversely, the genetic determinants involved in interactions of BCMNV strains with bc-1 resistance alleles have not yet been identified either. We performed a complete biological and molecular study of three isolates of BCMNV belonging to PG-III and VI, collected in California and in Oregon. Particular attention was paid to BCMNV isolates’ performance in common bean lines from host groups 2, 3, and 9, harboring bc-1 and bc-12 alleles. The data obtained suggest that the bc-1 alleles restricted systemic movement of PG-III isolates of BCMNV, while cell-tocell movement of the virus in inoculated leaves did not seem to be affected

ASSESSMENT OF THE RESISTANCE CONFERRED BY THE \u3ci\u3ebc-1\u3c/i\u3e ALLELES TO \u3ci\u3eBean common mosaic necrosis virus\u3c/i\u3e

INTRODUCTION: Bean common mosaic necrosis virus (BCMNV) is a potyvirus comprising several strains classified into two pathogroups according to the interactions with six recessive resistance alleles in common bean (1). These pathogroups (PGs), numbered III and VI, are defined by the ability (PG-VI) or inability (PG-III) of a BCMNV isolate to replicate in bean differential lines carrying bc-1 or bc-12 resistance alleles. The biological and molecular basis for this differential response of BCMNV isolates to the presence of bc-1 alleles is not known. Conversely, the genetic determinants involved in interactions of BCMNV strains with bc-1 resistance alleles have not yet been identified either. We performed a complete biological and molecular study of three isolates of BCMNV belonging to PG-III and VI, collected in California and in Oregon. Particular attention was paid to BCMNV isolates’ performance in common bean lines from host groups 2, 3, and 9, harboring bc-1 and bc-12 alleles. The data obtained suggest that the bc-1 alleles restricted systemic movement of PG-III isolates of BCMNV, while cell-tocell movement of the virus in inoculated leaves did not seem to be affected

Bean common mosaic virus Isolate Exhibits a Novel Pathogenicity Profile in Common Bean, Overcoming the bc-3 Resistance Allele Coding for the Mutated eIF4E Translation Initiation Factor

Resistance against Bean common mosaic virus (BCMV) in Phaseolus vulgaris is governed by six recessive resistance alleles at four loci. One of these alleles, bc-3, is able to protect P. vulgaris against all BCMV strains and against other potyviruses; bc-3 was identified as the eIF4E allele carrying mutated eukaryotic translation initiation factor gene. Here, we characterized a novel BCMV isolate 1755a that was able to overcome bc-2 and bc-3 alleles in common bean. Thus, it displayed a novel pattern of interactions with resistance genes in P. vulgaris, and was assigned to a new pathogroup, PG-VIII. The IVT7214 cultivar supporting the replication of BCMV-1755a was found to have the intact homozygous bc-3 cleaved amplified polymorphic sequences marker and corresponding mutations in the eIF4E allele that confer resistance to BCMV isolates from all other pathogroups as well as to other potyviruses. The VPg protein of 1755a had seven amino acid substitutions relative to VPgs of other BCMV isolates unable to overcome bc-3. The 1755a genome was found to be a recombinant between NL1, US1 (both PG-I), and a yet unknown BCMV strain. Analysis of the recombination patterns in the genomes of NL1 and US1 (PG-I), NY15P (PG-V), US10 and RU1-OR (PG-VII), and 1755a (PG-VIII), indicated that P1/HC-Pro cistrons of BCMV strains may interact with most resistance genes. This is the first report of a BCMV isolate able to overcome the bc-3 resistance allele, suggesting that the virus has evolved mechanisms to overcome multiple resistance genes available in common bean

Formal symplectic groupoid of a deformation quantization

We give a self-contained algebraic description of a formal symplectic groupoid over a Poisson manifold M. To each natural star product on M we then associate a canonical formal symplectic groupoid over M. Finally, we construct a unique formal symplectic groupoid `with separation of variables' over an arbitrary Kaehler-Poisson manifold.Comment: 41 page, Lemma 13, several typos and notations correcte

X-ray pulsar XTE J1858+034: discovery of the cyclotron line and the revised optical identification

We present results of a detailed investigation of the poorly studied X-ray pulsar XTE J1858+034 based on the data obtained with the NuSTAR observatory during the outburst of the source in 2019. The spectral analysis resulted in the discovery of a cyclotron absorption feature in the source spectrum at ~48 keV both in the pulse phase averaged and resolved spectra. Accurate X-ray localization of the source using the NuSTAR and Chandra observatories allowed us to accurately determine the position of the X-ray source and identify the optical companion of the pulsar. The analysis of the counterpart properties suggested that the system is likely a symbiotic binary hosting an X-ray pulsar and a late type companion star of K-M classes rather than Be X-ray binary as previously suggested.Comment: 12 pages, 12 figures, accepted by Ap

Folding of poly-amino acids and intrinsically disordered proteins in overcrowded milieu induced by pH change

pH-induced structural changes of the synthetic homopolypeptides poly-E, poly-K, poly-R, and intrinsically disordered proteins (IDPs) prothymosin alpha (ProT alpha) and linker histone H1, in concentrated PEG solutions simulating macromolecular crowding conditions within the membrane-less organelles, were characterized. The conformational transitions of the studied poly-amino acids in the concentrated PEG solutions depend on the polymerization degree of these homopolypeptides, the size of their side chains, the charge distribution of the side chains, and the crowding agent concentration. The results obtained for poly-amino acids are valid for IDPs having a significant total charge. The overcrowded conditions promote a significant increase in the cooperativity of the pH-induced coil-alpha-helix transition of ProTa and provoke histone H1 aggregation. The most favorable conditions for the pH-induced structural transitions in concentrated PEG solutions are realized when the charged residues are grouped in blocks, and when the distance between the end of the side group carrying charge and the backbone is small. Therefore, the block-wise distribution of charged residues within the IDPs not only plays an important role in the liquid-liquid phase transitions, but may also define the expressivity of structural transitions of these proteins in the overcrowded conditions of the membrane-less organelles. (C) 2018 Elsevier B.V. All rights reserved.Peer reviewe

Broad-band analysis of X-ray pulsar 2S 1845–024

We present the results of a detailed investigation of the poorly studied X-ray pulsar 2S 1845−024 based on data obtained at the NuSTAR observatory during the type I outburst in 2017. Neither pulse phase-averaged nor phase-resolved spectra of the source show evidence for a cyclotron absorption feature. We also used data obtained from other X-ray observatories (Swift, XMM-Newton and Chandra) to study the spectral properties as a function of orbital phase. The analysis reveals a high hydrogen column density for the source reaching ∼1024 cm−2 around periastron. Using high-quality Chandra data we were able to obtain an accurate localization of 2S 1845−024 at 18h48m16s.8 and Dec. = −2◦25'25".1 (J2000), which allowed us to use infrared (IR) data to roughly classify the optical counterpart of the source as an OB supergiant at a distance of ≳15 kpc.</p

Defective RNA Molecules Associated with Citrus Tristeza Virus

AbstractPreparations of single-stranded (ss) RNA extracted from particles of the Israeli VT strain of citrus tristeza virus (CTV-VT), and ss- and double-stranded (ds) RNA preparations extracted from infected Alemow (Citrus macrophylla) plants, contained a population of molecules with features that suggest that they are defective RNAs. The prototype of 2424 nt was cloned and sequenced and was found to be composed of two genomic regions corresponding to the 5′ (1151 nt) and the 3′ (1259 nt) termini of the genomic CTV-RNA, with two perfect direct repeats of eight nucleotides of unknown origin at the junction site. Northern hybridization analysis demonstrated that this 2.4-kb defective RNA is an abundant species among the other CTV-specific ss- and ds-RNAs in infected plants. The 2.4-kb RNA was found encapsidated by the CTV coat protein indicating that the CTV origin of assembly is located close to the 5′ or 3′ terminus. This is the first defective RNA to be reported for a member of the closterovirus group

X-Ray Pulsar XTE J1858+034: Discovery of the Cyclotron Line and the Revised Optical Identification

We present the results of a detailed investigation of the poorly studied X-ray pulsar (XRP) XTE J1858+034 based on the data obtained with the NuSTAR observatory during the outburst of the source in 2019. The spectral analysis resulted in the discovery of a cyclotron absorption feature in the source spectrum at similar to ~48 keV in both the pulse phase-averaged and resolved spectra. Accurate X-ray localization of the source using the NuSTAR and Chandra observatories allowed us to accurately determine the position of the X-ray source and identify the optical companion of the pulsar. The analysis of the counterpart properties suggested that the system is likely a symbiotic binary hosting an XRP and a late-type companion star of the K-M classes rather than a Be X-ray binary as previously suggested