scholarly journals Liberibacter crescens Is a Cultured Surrogate for Functional Genomics of Uncultured Pathogenic ‘Candidatus Liberibacter’ spp. and Is Naturally Competent for Transformation

2019 ◽  
Vol 109 (10) ◽  
pp. 1811-1819 ◽  
Author(s):  
M. Jain ◽  
L. Cai ◽  
L. A. Fleites ◽  
A. Munoz-Bodnar ◽  
M. J. Davis ◽  
...  
Keyword(s):  
Plasmid Dna ◽  
Plant Pathogens ◽  
Natural Transformation ◽  
Axenic Culture ◽  
Single Species ◽  
Potato Production ◽  
Regulatory Elements ◽  
Causal Agent ◽  
Circular Plasmid ◽  
Candidatus Liberibacter

‘Candidatus Liberibacter’ spp. are uncultured insect endosymbionts and phloem-limited bacterial plant pathogens associated with diseases ranging from severe to nearly asymptomatic. ‘Ca. L. asiaticus’, causal agent of Huanglongbing or citrus “greening,” and ‘Ca. L. solanacearum’, causal agent of potato zebra chip disease, respectively threaten citrus and potato production worldwide. Research on both pathogens has been stymied by the inability to culture these agents and to reinoculate into any host. Only a single isolate of a single species of Liberibacter, Liberibacter crescens, has been axenically cultured. L. crescens strain BT-1 is genetically tractable to standard molecular manipulation techniques and has been developed as a surrogate model for functional studies of genes, regulatory elements, promoters, and secreted effectors derived from the uncultured pathogenic Liberibacters. Detailed, step-by-step, and highly reproducible protocols for axenic culture, transformation, and targeted gene knockouts of L. crescens are described. In the course of developing these protocols, we found that L. crescens is also naturally competent for direct uptake and homology-guided chromosomal integration of both linear and circular plasmid DNA. The efficiency of natural transformation was about an order of magnitude higher using circular plasmid DNA compared with linearized fragments. Natural transformation using a replicative plasmid was obtained at a rate of approximately 900 transformants per microgram of plasmid, whereas electroporation using the same plasmid resulted in 6 × 104 transformants. Homology-guided marker interruptions using either natural uptake or electroporation of nonreplicative plasmids yielded 10 to 12 transformation events per microgram of DNA, whereas similar interruptions using linear fragments via natural uptake yielded up to 34 transformation events per microgram of DNA.

Detection of Rhizoctonia solani AG-2-2 IV, the Causal Agent of Large Patch of Zoysiagrass, Using Plasmid DNA as a Probe.

1998 ◽  
Vol 64 (5) ◽  
pp. 451-457 ◽  
Author(s):  
Susumu TAKAMATSU ◽  
Manami NAKANO ◽  
Hideyuki YOKOTA ◽  
Hitoshi KUNOH
Keyword(s):  
Rhizoctonia Solani ◽  
Plasmid Dna ◽  
Causal Agent ◽  
Large Patch

The taxonomical identity of the perfect state of Pyricularia grisea and its allies

1978 ◽  
Vol 56 (2) ◽  
pp. 180-183 ◽  
Author(s):  
H. Yaegashi ◽  
S. Udagawa
Keyword(s):  
Magnaporthe Grisea ◽  
Single Species ◽  
Causal Agent ◽  
Blast Disease ◽  
Stem Rot ◽  
Pyricularia Grisea ◽  
Perfect State ◽  
Conidial State

Magnaporthe grisea is proposed as a comb.nov. for Ceratosphaeria grisea Hébert, the perfect state of Pyricularia grisea (Cke.) Sacc. Pyricularia grisea is very close morphologically to P. oryzae Cav., well known as the causal agent of blast disease on rice. Magnaporthe was recently established in the Diaporthales to accommodate a single species, M. salvinii (Catt.) Krause & Webster, which was described as the cause of stem rot of rice with conidial state known as Nakataea sigmoidea Hara. Based on a review of the taxonomic characters of Ceratosphaeria grisea, the desirability is discussed of its inclusion in the genus Magnaporthe.

Fidelity of transcription of Xenopus laevis globin genes injected into Xenopus laevis oocytes and unfertilized eggs

1984 ◽  
Vol 4 (10) ◽  
pp. 2109-2119
Author(s):  
M M Bendig ◽  
J G Williams
Keyword(s):  
Xenopus Laevis ◽  
Chromatin Structure ◽  
Plasmid Dna ◽  
Xenopus Laevis Oocytes ◽  
Globin Genes ◽  
Low Level ◽  
Circular Plasmid

The Xenopus laevis alpha 1- and beta 1-globin genes were injected into oocytes and unfertilized eggs of X. laevis. In oocytes, the injected globin genes were actively transcribed, but the majority of the transcripts were incorrectly initiated. In unfertilized eggs, the injected genes were transcribed at a low level but only from the correct start sites. In oocytes, the injected circular plasmid DNA containing the cloned globin genes persisted but did not replicate. In contrast, DNA injected into unfertilized eggs replicated up to 15-fold within a 22-h period. We suggest that the ability of the egg to selectively transcribe the injected X. laevis globin genes from the correct promoter sites may be related to differences in chromatin structure between the oocyte and the unfertilized egg.

scholarly journals Potential Distribution and the Risks of Bactericera cockerelli and Its Associated Plant Pathogen Candidatus Liberibacter Solanacearum for Global Potato Production

Insects ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 298
Author(s):  
Jing Wan ◽  
Rui Wang ◽  
Yonglin Ren ◽  
Simon McKirdy
Keyword(s):  
At Risk ◽  
South America ◽  
Plant Pathogen ◽  
Potato Production ◽  
Economic Losses ◽  
Bactericera Cockerelli ◽  
Ecological Niche Models ◽  
Potato Acreage ◽  
Candidatus Liberibacter Solanacearum ◽  
Candidatus Liberibacter

The tomato potato psyllid (TPP), Bactericera cockerelli, is a psyllid native to North America that has recently invaded New Zealand and Australia. The potential for economic losses accompanying invasions of TPP and its associated bacterial plant pathogen Candidatus Liberibacter solanacearum (CLso), has caused much concern. Here, we employed ecological niche models to predict environments suitable for TPP/CLso on a global scale and then evaluated the extent to which global potato cultivation is at risk. In addition, at a finer scale the risk to the Australian potato acreage was evaluated. A total of 86 MaxEnt models were built using various combinations of settings and climatic predictors, and the best model based on model evaluation metrics was selected. Climatically suitable habitats were identified in Eurasia, Africa, South America, and Australasia. Intersecting the predicted suitability map with land use data showed that 79.06% of the global potato cultivation acreage, 96.14% of the potato production acreage in South America and Eurasia, and all the Australian potato cropping areas are at risk. The information generated by this study increases knowledge of the ecology of TPP/CLso and can be used by government agencies to make decisions about preventing the spread of TPP and CLso across the globe.

scholarly journals Translocation of ‘Candidatus Liberibacter solanacearum’, the Zebra Chip Pathogen, in Potato and Tomato

2011 ◽  
Vol 101 (11) ◽  
pp. 1285-1291 ◽  
Author(s):  
Julien Levy ◽  
Aravind Ravindran ◽  
Dennis Gross ◽  
Cecilia Tamborindeguy ◽  
Elizabeth Pierson
Keyword(s):  
Potato Production ◽  
Potato Cultivars ◽  
Zebra Chip ◽  
Tomato Plants ◽  
Candidatus Liberibacter Solanacearum ◽  
Single Leaf ◽  
Zebra Chip Disease ◽  
Candidatus Liberibacter ◽  
Inoculation Access Period ◽  
Polymerase Chain

Zebra Chip disease is a serious threat to potato production. The pathogen, the phloem-limited bacterium ‘Candidatus Liberibacter solanacearum,’ is vectored by the potato and tomato psyllid Bactericerca cockerelli to potato and tomato. Patterns of pathogen translocation through phloem in potato and tomato plants were examined to determine whether rate or direction of translocation vary by host species or potato cultivars. Two insects were given a 7-day inoculation access period on a single leaf. Weekly, leaves from upper-, middle-, and lower-tier branches were tested for the presence of ‘Ca. L. solanacearum’ by polymerase chain reaction (PCR). In tomato and potato, ‘Ca. L. solanacearum’ was detected 2 to 3 weeks after infestation, most frequently in upper- and middle-tier leaves. In potato, the pathogen was detected in leaves on a second, noninfested stem when the stems remained joined via the tuber. Although rates of pathogen movement were similar among potato cultivars, symptoms developed earlier in more susceptible cultivars. Quantitative PCR indicated that bacterial titers were frequently low in tomato and potato samples (<20 genome units per nanogram of DNA). Results establish that, for improved detection, samples should include newly developing leaves and consider that, under low insect pressure, the pathogen may be undetectable by PCR until 3 weeks after infestation.

scholarly journals The Probing Behavior Component of Disease Transmission in Insect-Transmitted Bacterial Plant Pathogens

Insects ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 212 ◽  
Author(s):  
Timothy A. Ebert
Keyword(s):  
Host Plant ◽  
Plant Resistance ◽  
Host Plant Resistance ◽  
Disease Transmission ◽  
Plant Pathogens ◽  
Management Strategies ◽  
Resistance Mechanism ◽  
Electrical Circuit ◽  
Plant Diseases ◽  
Candidatus Liberibacter

Insects can be effective vectors of plant diseases and this may result in billions of dollars in lost agricultural productivity. New, emerging or introduced diseases will continue to cause extensive damage in afflicted areas. Understanding how the vector acquires the pathogen and inoculates new hosts is critical in developing effective management strategies. Management may be an insecticide applied to kill the vector or a host plant resistance mechanism to make the host plant less suitable for the vector. In either case, the tactic must act before the insect performs the key behavior(s) resulting in either acquisition or transmission. This requires knowledge of the timing of behaviors the insect uses to probe the plant and commence ingestion. These behaviors are visualized using electropenetrography (EPG), wherein the plant and insect become part of an electrical circuit. With the tools to define specific steps in the probing process, we can understand the timing of acquisition and inoculation. With that understanding comes the potential for more relevant testing of management strategies, through insecticides or host plant resistance. The primary example will be Candidatus Liberibacter asiaticus transmitted by Diaphorina citri Kuwayama in the citrus agroecosystem, with additional examples used as appropriate.

scholarly journals Rational design of minimal synthetic promoters for plants

2020 ◽  
Vol 48 (21) ◽  
pp. 11845-11856 ◽  
Author(s):  
Yao-Min Cai ◽  
Kalyani Kallam ◽  
Henry Tidd ◽  
Giovanni Gendarini ◽  
Amanda Salzman ◽  
...  
Keyword(s):  
Rational Design ◽  
Plant Pathogens ◽  
Critical Role ◽  
Experimental System ◽  
Computational Design ◽  
Regulatory Elements ◽  
Regulatory Function ◽  
Synthetic Promoters ◽  
Sequence Elements ◽  
Plant Promoters

Abstract Promoters serve a critical role in establishing baseline transcriptional capacity through the recruitment of proteins, including transcription factors. Previously, a paucity of data for cis-regulatory elements in plants meant that it was challenging to determine which sequence elements in plant promoter sequences contributed to transcriptional function. In this study, we have identified functional elements in the promoters of plant genes and plant pathogens that utilize plant transcriptional machinery for gene expression. We have established a quantitative experimental system to investigate transcriptional function, investigating how identity, density and position contribute to regulatory function. We then identified permissive architectures for minimal synthetic plant promoters enabling the computational design of a suite of synthetic promoters of different strengths. These have been used to regulate the relative expression of output genes in simple genetic devices.

scholarly journals Natural Transformation of Plasmid DNA in Escherichia coli in Sterilized Soil Column

1970 ◽  
Vol 25 (1) ◽  
pp. 49-52
Author(s):  
M Mahabub-Uz-Zaman ◽  
Zia Uddin Ahmed
Keyword(s):  
Escherichia Coli ◽  
Plasmid Dna ◽  
Natural Transformation ◽  
Soil Column ◽  
Limiting Factor ◽  
Broad Host Range ◽  
E Coli ◽  
Competent Cells ◽  
Broad Host Range Plasmid ◽  
Plasmid Puc18

The present study was carried out to assess transformability of natural and laboratory strains of Escherichia coli by plasmid DNA under different transformation conditions in sterilized soil column. Transformation experiments were carried out in laboratory conditions and in sterile soil columns with CaCl2-treated competent cells and non-competent cells at log phase and stationary phase of growth using the broad host range plasmid pUC18. In soil column experiments, transformants were obtained after CaCl2 induced competence in both E. coli K12 DH5α and strain BM09 in the frequency of 10-8 to 10-9. In natural transformation assays, transformants appeared only in log phase cells of strain DH5α at a lower frequency (5.0 x 10-9), and in CaCl2-competent BM09 cells, but not in fresh cells. Thus the major limiting factor for natural transformation in environmental E. coli in soil column is probably the absence of a competent state. The significance of this finding has been discussed with respect to generally observed lower antibiotic resistance in environmental E. coli isolates from aquatic sources. Keywords: Natural transformation; Plasmid DNA; Escherichia coli; Competent stateDOI: http://dx.doi.org/10.3329/bjm.v25i1.4856 Bangladesh J Microbiol, Volume 25, Number 1, June 2008, pp 49-52

scholarly journals rRNA genes of Naegleria gruberi are carried exclusively on a 14-kilobase-pair plasmid.

1987 ◽  
Vol 7 (9) ◽  
pp. 3027-3031 ◽  
Author(s):  
C G Clark ◽  
G A Cross
Keyword(s):  
Ribosomal Dna ◽  
Plasmid Dna ◽  
Rrna Genes ◽  
Extrachromosomal Dna ◽  
The Third ◽  
Circular Plasmid ◽  
5.8S Rrna ◽  
Extrachromosomal Element ◽  
Naegleria Gruberi

An extrachromosomal DNA was discovered in Naegleria gruberi. The 3,000 to 5,000 copies per cell of this 14-kilobase-pair circular plasmid carry all the 18S, 28S, and 5.8S rRNA genes. The presence of the ribosomal DNA of an organism exclusively on a circular extrachromosomal element is without precedent, and Naegleria is only the third eucaryotic genus in which a nuclear plasmid DNA has been found.

Sign in / Sign up

Export Citation Format

Share Document