scholarly journals Resistance to Citrus Canker Caused by Xanthomonas axonopodis pv. citri in an Accession of Citrus sp. Similar to Grapefruit

Plant Disease ◽  
2008 ◽  
Vol 92 (4) ◽  
pp. 652-652 ◽  
Author(s):  
A. M. Gochez ◽  
B. I. Canteros
Keyword(s):  
High Resistance ◽  
Quantitative Resistance ◽  
Germplasm Collection ◽  
Citrus Canker ◽  
Citrus Paradisi ◽  
Xanthomonas Axonopodis ◽  
Citrus Germplasm ◽  
Entre Rios ◽  
Short Time

Citrus canker is caused by Xanthomonas axonopodis pv. citri. All grapefruit (Citrus paradisi Macf.) cultivars are highly susceptible to the A-group strains of Xanthomonas axonopodis pv. citri. A type of grapefruit (Citrus sp.) called Dalan Dan (DD) has shown high resistance in the field in Misiones, Argentina where it is widely planted. The DD is Accession No. NC678 in the Campinas Citrus Germplasm Collection (Centro APTA Citrus Sylvio Moreira, Cordeiropolis, SP, Brazil) and Accession No. CCC-618 Dalan Dan in the Argentina Citrus Germplasm Collection at INTA (Concordia, Entre Ríos). Molecular studies completed in Brazil have shown high similarities among grapefruit varieties and DD (1). We report here the characterization of quantitative resistance to citrus canker in DD. Quantitative resistance in citrus is expressed as lower number of lesions per leaf area (3). Lesions per square centimeter were calculated after 3 to 4 weeks of two sets of inoculation of three inoculum levels (5 × 102, 2.5 × 103, and 5 × 103 cells per ml) in leaves of developing leaf flushes. The period of greatest susceptibility in DD was 15 to 23 days for the three inoculum levels; 1.35 ± 0.34 to 0.01 ± 0.01, 4.98 ± 0.91 to 0.91 ± 0.48, and 9.85 ± 2.17 to 1.91 ± 1.37 lesions per cm2, respectively. By contrast, the period of greatest susceptibility in grapefruit cv. Duncan was 15 to 29 days for the same three inoculum levels; 2.78 ± 0.46 to 1.22 ± 0.39, 17.29 ± 2.79 to 5.55 ± 0.93, and 22.87 ± 3.27 to 11.95 ± 3.55 lesions per cm2, respectively. The results shown here suggest that the DD citrus accession is susceptible to citrus canker for a very short time during the development of leaf flushes, which results in very high resistance in the field. This citrus germplasm material could be valuable as a source of resistance to improve other varieties or as a replacement of grapefruit due to the similar fruit and juice qualities. References: (1) M. J. Corazza-Nunes et al. Euphytica 126:169, 2002. (2) M. J. Corazza-Nunes et al. Summa Phytopathol. 32:322, 2006. (3) R. E. Stall et al. Phytopathology 72:1097, 1982.

scholarly journals (262) Screening Citrus Germplasm for Resistance to Xanthomonas axonopodis pv. Citri

HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 1048E-1049 ◽  
Author(s):  
Greg McCollum ◽  
Kim Bowman ◽  
Tim Gottwald
Keyword(s):  
Effective Means ◽  
Citrus Canker ◽  
Poncirus Trifoliata ◽  
Citrus Species ◽  
Citrus Industry ◽  
Xanthomonas Axonopodis ◽  
Citrus Germplasm ◽  
Citrus Bacterial Canker ◽  
Key Lime ◽  
Needle Prick

Citrus bacterial canker [causal agent Xanthomonas axonopodis pv. citri (Xac)] is a serious threat to the citrus industry. Currently, there are no effective means to control citrus canker. Our objective was to determine the resistance of selected citrus species, citrus hybrids, and citrus relatives to Xac. Our first experiment focused on determining if differences in resistance exist among 20 C. reticulata genotypes and included three other citrus species and citrus relatives (Glycosmis pentaphylla and Clausena hardimandiana). Plants were inoculated with Xac strain A either by injection infiltration or needle-prick. Our second experiment included 10 members of the genus Citrus and Poncirus trifoliata, representing a total of 31 different selections. Plants were needle-prick inoculated with both Xac strain A and Xac strain A Wellington (AW). All inoculations were done using suspensions of Xac at a concentration of 104 cfu/mL. In both experiments, there were highly significant differences among genotypes in response to inoculation with Xac. In the first experiment, regardless of inoculation method, G. pentaphylla and C. hardimandiana were found to be highly resistant to Xac, whereas C. paradisi was least resistant. In the second experiment for both Xac strain A and AW, Chinotto sour orange, Carrizo citrange, Eustis limequat, and P. trifoliata were the most resistant. Thornless key lime × Meiwa kumquat hybrids showed a range of resistance from among the most susceptible to among the most resistant. Our results expand on previous studies on resistance of citrus and citrus relatives to Xac and indicate that there may be potential for increasing resistance by breeding using selected parents.

Rapid, Refined, and Robust Method for Expression, Purification, and Characterization of Recombinant Human Amyloid-beta M1-42

2019 ◽  
Author(s):  
Priya Prakash ◽  
Travis Lantz ◽  
Krupal P. Jethava ◽  
Gaurav Chopra
Keyword(s):  
Amyloid Beta ◽  
Western Blots ◽  
Force Microscopy ◽  
E Coli ◽  
Atomic Force ◽  
Set Up ◽  
Short Time

Amyloid plaques found in the brains of Alzheimer’s disease (AD) patients primarily consists of amyloid beta 1-42 (Ab42). Commercially, Ab42 is synthetized using peptide synthesizers. We describe a robust methodology for expression of recombinant human Ab(M1-42) in Rosetta(DE3)pLysS and BL21(DE3)pLysS competent E. coli with refined and rapid analytical purification techniques. The peptide is isolated and purified from the transformed cells using an optimized set-up for reverse-phase HPLC protocol, using commonly available C18 columns, yielding high amounts of peptide (~15-20 mg per 1 L culture) in a short time. The recombinant Ab(M1-42) forms characteristic aggregates similar to synthetic Ab42 aggregates as verified by western blots and atomic force microscopy to warrant future biological use. Our rapid, refined, and robust technique to purify human Ab(M1-42) can be used to synthesize chemical probes for several downstream in vitro and in vivo assays to facilitate AD research.

PROSPECTS FOR THE USE OF REMOTE CROSS IN THE CITRUS CROPS SELECTION

1970 ◽  
pp. 46-49 ◽  
Author(s):  
R. V. Kulyan
Keyword(s):  
Complex Traits ◽  
Germplasm Collection ◽  
Early Maturity ◽  
Russian Research Institute ◽  
Citrus Germplasm ◽  
The Status ◽  
New Varieties ◽  
Primary Test ◽  
Growing Conditions ◽  
Positive Traits

The Russian Research Institute of Floriculture and Subtropical Crops has the citrus germplasm collection, in total over 150 genotypes of various origins including 30 wild and semi-wild relatives. As a result of controlled hybridization in 17 crossings combinations of with the participation of relatives of citrus plants, new 769 hybrid offspring were obtained, which combine the traits of both the maternal and paternal genotypes. Analyzing the populations, promising combinations were highlighted: C. reticulata × Fortunella margarita (47.1%); C. x natsudaidai × 3252 (42.1%) and C. reticulata × C. reticulata ‘Cleopatra’ (40.9%) to create the gene pool of distant hybrids. From the mentioned combinations of crossings the greatest percent of seedlings which phenotypes tend to cultivated varieties was received. This hybrid material is a valuable source for isolating forms that are resistant to extreme environmental factors. According to phenotypic characteristics, hybrids were divided into three categories: I – Cultural, II – Semi-wild and III – Wild. Of the first category, the largest number 87 prospective forms were selected, and can be of interest for further breeding. As a result of the study of interspecific hybrid seedlings, 137 promising forms have been identified, which are carriers the complex traits such as dwarfism, thornless, early maturity and increased winter hardiness. From this set 17 genotypes were selected, which received the status of an elite forms, which successfully pass the primary test, and will be also useful in further breeding work for creating sources with a complex of positive traits and on breeding new varieties of citrus crops resistant to growing conditions.

Characterization of a Resistive Path to a Gate Node Using Tunneling Current Measurements

2010 ◽  
Author(s):  
Clifford Howard ◽  
Sam Subramanian ◽  
Kent Erington ◽  
Randall Mulder ◽  
Yuk Tsang ◽  
...  
Keyword(s):  
High Resistance ◽  
Tunneling Current ◽  
Resistance Measurement ◽  
Gate Leakage ◽  
Advanced Technologies

Abstract Advanced technologies with higher gate leakage due to oxide tunneling current enable detection of high resistance faults to gate nodes using a straight forward resistance measurement.

scholarly journals Synthesis and characterization of Cu(OH)2-NWs-PVA-AC Nano-composite and its use as an efficient adsorbent for removal of methylene blue

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sivarama Krishna Lakkaboyana ◽  
Khantong Soontarapa ◽  
Nabel Kalel Asmel ◽  
Vinay Kumar ◽  
Ravi Kumar Marella ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Kinetic Models ◽  
Batch Reactor ◽  
Maximum Adsorption Capacity ◽  
Nano Composite ◽  
Adsorption Processes ◽  
Intra Particle Diffusion ◽  
Short Time ◽  
Efficient Adsorbent

AbstractThe present study focused on the synthesis of copper hydroxide nanowires decorated on activated carbon (Cu(OH)2-NWs-PVA-AC). The obtained Cu(OH)2-NWs-PVA-AC Nano-composite was distinguished by XRD, SEM, EDX, BET, FTIR and XPS respectively. Besides, different variables such as solution pH, and initial dye concentration, contact time, and temperature were performed on the adsorption efficiency of MB in a small batch reactor. Further, the experimental results are analyzed by various kinetic models via PFO, PSO, intra-particle diffusion and Elovich models, and the results revealed that among the kinetic models, PSO shows more suitability. In addition, different adsorption isotherms were applied to the obtained experimental data and found that Langmuir–Freundlich and Langmuir isotherm were best fits with the maximum adsorption capacity of 139.9 and 107.6 mg/g, respectively. The Nano-composite has outstanding MB removal efficiency of 94–98.5% with a span of 10 min. and decent adsorption of about 98.5% at a pH of 10. Thermodynamic constants like Gibbs free energy, entropy, and enthalpy were analyzed from the temperature reliance. The results reveal the adsorption processes are spontaneous and exothermic in nature. The high negative value of ΔG° (− 44.11 to − 48.86 kJ/mol) and a low negative value of ΔH° (− 28.96 kJ/mol) show the feasibility and exothermic nature of the adsorption process. The synthesized dye was found to be an efficient adsorbent for the potential removal of cationic dye (methylene blue) from wastewater within a short time.

scholarly journals Characterization of Xanthomonas axonopodis pv. phaseoli isolates

2008 ◽  
Vol 34 (3) ◽  
pp. 228-231 ◽  
Author(s):  
Willian Mário de Carvalho Nunes ◽  
Maria Júlia Corazza ◽  
Silvana Aparecida Crestes Dias de Souza ◽  
Siu Mui Tsai ◽  
Eiko Eurya Kuramae
Keyword(s):  
Xanthomonas Campestris ◽  
Random Amplified Polymorphic Dna ◽  
Hypersensitive Reaction ◽  
Chain Reaction ◽  
Xanthomonas Axonopodis ◽  
Paulo State ◽  
Total Dna ◽  
Polymerase Chain ◽  
Bacterial Plant Pathogen

A simple, quick and easy protocol was standardized for extraction of total DNA of the bacteria Xanthomonas axonopodis pv. phaseoli. The DNA obtained by this method had high quality and the quantity was enough for the Random Amplified Polymorphic DNA (RAPD) reactions with random primers, and Polymerase Chain Reaction (PCR) with primers of the hypersensitivity and pathogenicity gene (hrp). The DNA obtained was free of contamination by proteins or carbohydrates. The ratio 260nm/380nm of the DNA extracted ranged from 1.7 to 1.8. The hrp gene cluster is required by bacterial plant pathogen to produce symptoms on susceptible hosts and hypersensitive reaction on resistant hosts. This gene has been found in different bacteria as well as in Xanthomonas campestris pv. vesicatoria (9). The primers RST21 and RST22 (9) were used to amplify the hrp gene of nine different isolates of Xanthomonas axonopodis pv. phaseoli from Botucatu, São Paulo State, Brazil, and one isolate, "Davis". PCR amplified products were obtained in all isolates pathogenic to beans.

scholarly journals Genetic diversity of table grape based on morphoagronomic traits

2011 ◽  
Vol 68 (1) ◽  
pp. 42-49 ◽  
Author(s):  
Patrícia Coelho de Souza Leão ◽  
Cosme Damião Cruz ◽  
Sérgio Yoshimitsu Motoike
Keyword(s):  
Genetic Diversity ◽  
Clustering Analysis ◽  
Germplasm Collection ◽  
Table Grape ◽  
Cluster Method ◽  
Breeding Programs ◽  
Method Analysis ◽  
Vitis Spp ◽  
Grape Cultivars

The conservation and characterization of grape (Vitis spp) genetic resources in germplasm banks have been the basis of its use in breeding programs that result in development of new cultivars. There are at least 10,000 grape cultivars kept in germplasm collection. The genetic diversity in 136 table grape accessions from the state of Bahia, Brazil, was evaluated. Continuous and discrete morphoagronomic traits were assessed. The clustering analysis by the Tocher otimization method resulted in 30 clusters (considering continuous morphoagronomic traits), and 9 clusters (taking into consideration multicategorical traits). There was no agreement between clusters obtained by both, continuous or discrete phenotypic descriptors, independent of the cluster method analysis used. A satisfactory genetic variability among the table grape accessions was observed.

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