Population Dynamics and Seasonal Fluctuation in the Percentage Infection ofTrioza erytreaewith ‘Candidatus’ Liberibacter Africanus, the African Citrus Greening Pathogen, in an Orchard Severely Infected with African Greening and Transmission by Field-CollectedTrioza erytreae

2014 ◽  
Vol 22 (1) ◽  
pp. 127-135 ◽  
Author(s):  
G. Cook ◽  
V.Z. Maqutu ◽  
S.P. van Vuuren
Keyword(s):  
Population Dynamics ◽  
Seasonal Fluctuation ◽  
Citrus Greening ◽  
Candidatus Liberibacter

scholarly journals Tracing Penicillin Movement in Citrus Plants Using Fluorescence-Labeled Penicillin

Antibiotics ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 262
Author(s):  
Nabil Killiny ◽  
Pedro Gonzalez-Blanco ◽  
Yulica Santos-Ortega ◽  
Fuad Al-Rimawi ◽  
Amit Levy ◽  
...  
Keyword(s):  
Vascular Tissue ◽  
Vascular System ◽  
Citrus Greening ◽  
Application Site ◽  
Asian Citrus Psyllid ◽  
Diaphorina Citri ◽  
Candidatus Liberibacter Asiaticus ◽  
Citrus Industry ◽  
Candidatus Liberibacter ◽  
Liberibacter Asiaticus

Huánglóngbìng (HLB), citrus greening, is one of the most destructive diseases of citrus plants worldwide. In North America, HLB is caused by the phloem-limited bacterium Candidatus Liberibacter asiaticus and is transmitted by the Asian citrus psyllid, Diaphorina citri. No cure exists at present, and the use of antibiotics for the control of HLB has gained interest due to the significant losses to the citrus industry. Because of unsatisfactory results when using foliar applications of antibiotics, concerns were raised regarding the uptake and translocation of these materials within trees. We, therefore, investigated a method that allows us to study the movement of antibiotic materials in citrus plants. Herein, we utilized a fluorescence-labeled penicillin, BOCILLIN™ FL-Penicillin (FL-penicillin), to study the uptake and translocation of penicillin in citrus plants. FL-penicillin was applied by puncture to the stem of young citrus seedlings and was traced by using fluorescence microscopy. After application, we detected FL-penicillin in the leaves and in the stem xylem and phloem tissues above and below the application site in both intact and partially bark-girdled citrus seedlings, indicating that it is easily taken up and transported through the plant vascular system. In addition, we detected FL-penicillin in the gut of D. citri, which were allowed to feed on the treated plants, suggesting translocation of this molecule into the vascular tissue. We propose that the use of fluorescent-labeled molecules could be an effective tool for understanding the uptake and translocation of antibiotics and other macromolecules in plants and insects.

scholarly journals Early Events of Citrus Greening (Huanglongbing) Disease Development at the Ultrastructural Level

2010 ◽  
Vol 100 (9) ◽  
pp. 949-958 ◽  
Author(s):  
Svetlana Y. Folimonova ◽  
Diann S. Achor
Keyword(s):  
Middle Lamella ◽  
Ultrastructural Level ◽  
Citrus Greening ◽  
Ultrastructural Changes ◽  
Bacterial Cells ◽  
Tissue Samples ◽  
Large Numbers ◽  
Presymptomatic Stage ◽  
Candidatus Liberibacter ◽  
Advanced Stages

Citrus greening (Huanglongbing [HLB]) is one of the most destructive diseases of citrus worldwide. The causal agent of HLB in Florida is thought to be ‘Candidatus Liberibacter asiaticus’. Understanding of the early events in HLB infection is critical for the development of effective measures to control the disease. In this work, we conducted cytopathological studies by following the development of the disease in citrus trees graft inoculated with ‘Ca. L. asiaticus’-containing material under greenhouse conditions to examine the correlation between ultrastructural changes and symptom production, with the main objective of characterizing the early events of infection. Based on our observations, one of the first degenerative changes induced upon invasion of the pathogen appears to be swelling of middle lamella between cell walls surrounding sieve elements. This anatomical aberration was often observed in samples from newly growing flushes in inoculated sweet orange and grapefruit trees at the early “presymptomatic” stage of HLB infection. Development of symptoms and their progression correlated with an increasing degree of microscopic aberrations. Remarkably, the ability to observe the bacterium in the infected tissue also correlated with the degree of the disease progression. Large numbers of bacterial cells were found in phloem sieve tubes in tissue samples from presymptomatic young flushes. In contrast, we did not observe the bacteria in highly symptomatic leaf samples, suggesting a possibility that, at more advanced stages of the disease, a major proportion of ‘Ca. L. asiaticus’ is present in a nonviable state. We trust that observations reported here advance our understanding of how ‘Ca. L. asiaticus’ causes disease. Furthermore, they may be an important aid in answering a question: when and where within an infected tree the tissue serves as a better inoculum source for acquisition and transmission of the bacterium by its psyllid vector.

scholarly journals ‘Ca. Liberibacter asiaticus’ Carries an Excision Plasmid Prophage and a Chromosomally Integrated Prophage That Becomes Lytic in Plant Infections

2011 ◽  
Vol 24 (4) ◽  
pp. 458-468 ◽  
Author(s):  
Shujian Zhang ◽  
Zomary Flores-Cruz ◽  
Lijuan Zhou ◽  
Byung-Ho Kang ◽  
Laura A. Fleites ◽  
...  
Keyword(s):  
Lytic Cycle ◽  
Citrus Greening ◽  
In Planta ◽  
Dna Library ◽  
Transmission Electron ◽  
Candidatus Liberibacter ◽  
Liberibacter Asiaticus ◽  
Lysogenic Conversion ◽  
Florida Citrus ◽  
Alpha Proteobacteria

Huanglongbing (HLB), also known as citrus greening, is a lethal disease of citrus caused by several species of ‘Candidatus Liberibacter’, a psyllid-transmitted, phloem-limited, alpha proteobacteria. ‘Ca. Liberibacter asiaticus’ is widespread in Florida citrus. The recently published ‘Ca. L. asiaticus’ psy62 genome, derived from a psyllid, revealed a prophage-like region of DNA in the genome, but phage have not been associated with ‘Ca. L. asiaticus’ to date. In the present study, shotgun sequencing and a fosmid DNA library of curated ‘Ca. L. asiaticus’ UF506, originally derived from citrus symptomatic for HLB, revealed two largely homologous, circular phage genomes, SC1 and SC2. SC2 encoded putative adhesin and peroxidase genes that had not previously been identified in ‘Ca. L. asiaticus’ and which may be involved in lysogenic conversion. SC2 also appeared to lack lytic cycle genes and replicated as a prophage excision plasmid, in addition to being found integrated in tandem with SC1 in the UF506 chromosome. By contrast, SC1 carried suspected lytic cycle genes and was found in nonintegrated, lytic cycle forms only in planta. Phage particles associated with ‘Ca. L. asiaticus’ were found in the phloem of infected periwinkles by transmission electron microscopy. In psyllids, both SC1 and SC2 were found only as prophage.

scholarly journals Densidad de microorganismos en rizósfera de limón mexicano con HuangLongBing e inoculado con hongos micorrízicos arbusculares y bacterias benéficas en invernadero.

2019 ◽  
Vol 37 (4) ◽  
pp. 379
Author(s):  
Christian Salvador Mendoza-Hernández ◽  
Evangelina Esmeralda Quiñones-Aguilar ◽  
Guadalupe Esperanza López-Ramírez ◽  
Luis López-Pérez ◽  
Gabriel Rincón-Enríquez
Keyword(s):  
Population Dynamics ◽  
Dilution Method ◽  
Agricultural Activity ◽  
Organic Fertilization ◽  
Chemical Fertilization ◽  
Randomized Experimental Design ◽  
Candidatus Liberibacter ◽  
Liberibacter Asiaticus ◽  
Old Trees ◽  
Total Bacteria

Mexico is among the first producers of Mexican lime (Ml), with 2.5 million hectares per year. Currently, this agricultural activity is threatened by HuangLonBing (HLB), caused by the bacterium Candidatus Liberibacter asiaticus (CLas). The development of biotechnological strategies aimed at combating this disease is imperative in order to incorporate them into the current management. The objective of our study was to isolate and determine the abundance of total bacteria (B) and filamentous fungi (FF) in the rhizosphere of Ml plants infected with CLas, treated with Bacillus subtilis (BS) and Funneliformis mosseae (FM). A completely randomized experimental design was used in six treatments and five replicates with one and a half year old trees infected with CLas via bud grafting as follows: 1) monthly application of BS (5 × 105 CFU g-1 of substrate: BsCLas), 2) single application of FM (5 spores g-1 inoculum: FmCLas); 3) chemical fertilization without CLas (Q), 4) chemical fertilization with CLas (QCLas); 5) organic fertilization without CLas (O) and 6) organic fertilization with CLas (OCLas). Five rhizospheric samplings were carried out each 70 days after the first application (dafa) of the chemical and organic nutrition of after the inoculation of microorganisms. The populations of bacteria (B) and fungi (FF) were determined using the decimal dilution method, plating (AN and PDA) and CFU count. Statistical differences (Tukey’s, P ≤ 0.05) were found in the population dynamics of B and total FF in treatments infected with CLas, with regard to non-infected treatments. At 368 dafa, total substrate B were 7.4 × 105 CFU g-1 in treatment QCLas, in contrast, total substrate B were 2.67 × 106 CFU g-1 in treatment Q. The population dynamics of B was the most affected compared to that of FF. The inoculation of beneficial microorganisms or application of organic nutrition were unable to maintain total B populations.

scholarly journals IMPACT OF IMPROVED DNA EXTRACTION METHOD FROM CITRUS LEAVES MIDRIB AND PCR FOR THE DETECTION OF CITRUS GREENING (CANDIDATUS LIBERIBACTER)

2021 ◽  
Vol 33 (1) ◽  
pp. 161-170
Author(s):  
Muhammad Nauman ◽  
Ummad U.D. Umar ◽  
Syed A.H. Naqvi ◽  
Ateeq U. Rehman ◽  
Muhammad T. Malik ◽  
...  
Keyword(s):  
Dna Extraction ◽  
Extraction Method ◽  
Citrus Greening ◽  
Dna Extraction Method ◽  
Candidatus Liberibacter ◽  
Citrus Leaves

scholarly journals Mitochondrial genetic variation reveals phylogeographic structure and cryptic diversity in Trioza erytreae

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Inusa Ajene ◽  
Fathiya M. Khamis ◽  
Gerhard Pietersen ◽  
Barbara van Asch
Keyword(s):  
South Africa ◽  
Citrus Greening ◽  
Phylogeographic Structure ◽  
Citrus Greening Disease ◽  
Trioza Erytreae ◽  
Baseline Information ◽  
Candidatus Liberibacter ◽  
Mitochondrial Sequences ◽  
Greening Disease ◽  
Genetic Clustering

AbstractTrioza erytreae is the main vector for ‘Candidatus Liberibacter africanus’, the causative agent of African Citrus Greening disease. The insect is widespread in Africa, and has recently disseminated to Southwestern Europe. This study aimed at generating reference mitogenome sequences for T. erytreae, as a background for future genetic diversity surveys. Complete mitochondrial sequences of three specimens collected in Ethiopia, Uganda and South Africa were recovered using Ion Torrent technology. The mitogenomes of T. erytreae from Uganda and Ethiopia were highly similar, and distinct from that found in South Africa. The phylogeographic structure of T. erytreae was assessed using genetic clustering and pairwise distances, based on a dataset of public COI sequences recorded as T. erytreae. The dataset revealed ten haplotypes with strong phylogeographic structure in Africa and Europe. Three haplotypes found in Kenya on Clausena anisata belonged to pairs separated by distances as high as 11.2%, and were basal to all other sequences. These results indicate that not all sequences identified as T. erytreae belong to the same species, and that some degree of specificity with different plant hosts is likely to exist. This study provides new baseline information on the diversity of T. erytreae, with potential implications for the epidemiology of African Citrus Greening disease.

Sign in / Sign up

Export Citation Format

Share Document