scholarly journals New Perspectives on the Epidemiology of Citrus Stubborn Disease in California Orchards

2010 ◽  
Vol 11 (1) ◽  
pp. 37
Author(s):  
Alexandre F. S. Mello ◽  
Raymond K. Yokomi ◽  
Ulrich Melcher ◽  
Jianchi Chen ◽  
Edwin Civerolo ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Fruit Quality ◽  
Pathogen Detection ◽  
Disease Incidence ◽  
Sampling Technique ◽  
The United States ◽  
Citrus Industry ◽  
Spiroplasma Citri ◽  
Specific Pcr ◽  
Citrus Stubborn Disease

Although citrus stubborn disease (CSD), caused by the phloem resident mollicute Spiroplasma citri, is a significant threat to California citrus industry, our knowledge of its epidemiology is mostly anecdotal. We optimized multiple pathogen-detection protocols, measured disease incidence in two plots of commercial California groves, assessed pathogen impact on fruit quality and yield, and evaluated genetic diversity among S. citri isolates. Fruit columellas and receptacles were more suitable than leaves or bark for bacterial cultivation. Using cultivation and S. citri-specific PCR for detection, the incidence of CSD in two orchards, respectively, ranged from 46 to 85% and 1 to 4%, depending on the sampling technique. Yield and quality of fruits produced by trees that were mildly or severely CSD-symptomatic were compared to those of S. citri-free trees in one California orchard in 2006 and 2007. These infected trees had reduced fruit quality and up to 32% lower yield relative to S. citri-free trees. Using RAPD markers to compare 35 S. citri isolates collected 20 years ago from the United States and Mediterranean region with 34 isolates recently collected from California, significant genetic diversity was identified but was not correlated with the time or location of collection. Our findings suggest that CSD incidence in the commercial groves evaluated could be as high as 85% and its impact on yield and fruit quality are significant. Accepted for publication 1 March 2010. Published 26 May 2010.

scholarly journals Evaluation of Host Resistance to Botrytis Bunch Rot in Vitis spp. and Its Correlation with Botrytis Leaf Spot

HortScience ◽  
2018 ◽  
Vol 53 (2) ◽  
pp. 204-207 ◽  
Author(s):  
Rachel P. Naegele
Keyword(s):  
Fruit Quality ◽  
Host Resistance ◽  
Leaf Spot ◽  
Disease Incidence ◽  
The United States ◽  
Soluble Solids ◽  
Postharvest Disease ◽  
Breeding Lines ◽  
Bunch Rot ◽  
Moderate Resistance

Botrytis cinerea, the causal agent of Botrytis bunch rot and gray mold, is the number one postharvest disease of fresh grapes in the United States. Fungicide applications are used to manage the disease, but fungicide-resistant isolates are common and postharvest losses occur annually. Host resistance is needed for long-term management of the disease. Sources of resistance in grape have been identified, but often have poor fruit quality. In this study, 27 grape lines (cultigens and species), including high fruit–quality Vitis vinifera, were evaluated for fruit and leaf susceptibility to two isolates of B. cinerea. No significant differences in virulence or pathogenicity were detected between the two isolates, but differences in disease incidence were evident among lines in leaves and berries. Most V. vinifera cultivars evaluated had high disease incidence in berries, whereas complex hybrids, Vitis aestivalus and Vitis arizonica, had low- to moderate disease incidence. Two V. vinifera breeding lines had moderate susceptibility (<50% disease) to Botrytis bunch rot when inoculated with either isolate. Only one V. vinifera line had little (<5%) to no berry or leaf disease when inoculated with either isolate. Moderate resistance (10% to 25%) was detected in Vitis spp., and a single V. vinifera line. Correlations were examined among soluble solids, leaf susceptibility, and fruit susceptibility. No correlations between soluble solids and disease susceptibility (leaves or berries) were identified, but moderate correlations between leaf and berry susceptibility were observed. Moderate resistance to Botrytis bunch rot and leaf spot were detected in Vitis breeding lines, suggesting these may be useful for developing grape cultivars with high fruit quality and resistance to B. cinerea.

scholarly journals Genome analysis of Spiroplasma citri strains from different host plants and its leafhopper vectors

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Rachel Rattner ◽  
Shree Prasad Thapa ◽  
Tyler Dang ◽  
Fatima Osman ◽  
Vijayanandraj Selvaraj ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Host Range ◽  
Genetic Relationships ◽  
Phylogenetic Analyses ◽  
The United States ◽  
Weed Species ◽  
Protein Coding ◽  
Spiroplasma Citri ◽  
Beet Leafhopper ◽  
Separate Branch

Abstract Background Spiroplasma citri comprises a bacterial complex that cause diseases in citrus, horseradish, carrot, sesame, and also infects a wide array of ornamental and weed species. S. citri is transmitted in a persistent propagative manner by the beet leafhopper, Neoaliturus tenellus in North America and Circulifer haematoceps in the Mediterranean region. Leafhopper transmission and the pathogen’s wide host range serve as drivers of genetic diversity. This diversity was examined in silico by comparing the genome sequences of seven S. citri strains from the United States (BR12, CC-2, C5, C189, LB 319, BLH-13, and BLH-MB) collected from different hosts and times with other publicly available spiroplasmas. Results Phylogenetic analysis using 16S rRNA sequences from 39 spiroplasmas obtained from NCBI database showed that S. citri strains, along with S. kunkelii and S. phoeniceum, two other plant pathogenic spiroplasmas, formed a monophyletic group. To refine genetic relationships among S. citri strains, phylogenetic analyses with 863 core orthologous sequences were performed. Strains that clustered together were: CC-2 and C5; C189 and R8-A2; BR12, BLH-MB, BLH-13 and LB 319. Strain GII3–3X remained in a separate branch. Sequence rearrangements were observed among S. citri strains, predominantly in the center of the chromosome. One to nine plasmids were identified in the seven S. citri strains analyzed in this study. Plasmids were most abundant in strains isolated from the beet leafhopper, followed by strains from carrot, Chinese cabbage, horseradish, and citrus, respectively. All these S. citri strains contained one plasmid with high similarity to plasmid pSci6 from S. citri strain GII3–3X which is known to confer insect transmissibility. Additionally, 17 to 25 prophage-like elements were identified in these genomes, which may promote rearrangements and contribute to repetitive regions. Conclusions The genome of seven S. citri strains were found to contain a single circularized chromosome, ranging from 1.58 Mbp to 1.74 Mbp and 1597–2232 protein-coding genes. These strains possessed a plasmid similar to pSci6 from the GII3–3X strain associated with leafhopper transmission. Prophage sequences found in the S. citri genomes may contribute to the extension of its host range. These findings increase our understanding of S. citri genetic diversity.

scholarly journals Genome analysis of Spiroplasma citri strains from different host plants and its leafhopper vectors

2020 ◽  
Author(s):  
Rachel Rattner ◽  
Shree Prasad Thapa ◽  
Tyler Dang ◽  
Fatima Osman ◽  
Vijayanandraj Selvaraj ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Host Range ◽  
Genetic Relationships ◽  
Phylogenetic Analyses ◽  
The United States ◽  
Weed Species ◽  
Protein Coding ◽  
Spiroplasma Citri ◽  
Beet Leafhopper ◽  
Separate Branch

Abstract Background Spiroplasma citri comprises a complex of bacteria that cause diseases in citrus, horseradish, carrot, sesame, and also infect a wide array of ornamental and weed species. S. citri is transmitted in a persistent propagative manner by the beet leafhopper, Neoaliturus tenellus in North America and Circulifer haematoceps in the Mediterranean region. Leafhopper transmission and the pathogen’s wide host range serve as drivers of genetic diversity. This diversity was examined by comparing the genome sequences of seven S. citri strains from the United States (BR12, CC2, C5, C189, LB319, BLH-13, and BLH-MB) collected from different hosts and times with other publicly available spiroplasmas.Results Phylogenetic analysis using 16S rRNA sequences from 39 spiroplasmas obtained from NCBI database showed that S. citri strains, along with S. kunkelii and S. phoeniceum, two other plant pathogenic spiroplasmas, formed a monophyletic group. To refine genetic relationships among S. citri strains, phylogenetic analyses with 863 core orthologous sequences were performed. Strains that clustered together were: CC-12 and C5; C189 and R8-A2; BR12, BLH-MB, BLH13 and LB 319. Strain GII3-3 remained in a separate branch. Sequence rearrangements were observed among S. citri strains, predominantly in the center of the chromosome. One to nine plasmids were identified in the seven S. citri strains analyzed in this study. Plasmids were most abundant in strains isolated from the beet leafhopper, followed by strains from carrot, Chinese cabbage, horseradish and citrus, respectively. All these S. citri strains contained one plasmid with high similarity to plasmid pSci6 from S. citri strain GII3-3X which is known to confer insect transmissibility. Additionally, 17 to 25 prophage-like elements were identified in these genomes, which may promote rearrangements and contribute to repetitive regions. Conclusions The genome of seven S. citri strains were found to contain a single circularized chromosome, ranging from 1.58 Mbp to 1.74 Mbp and 1,597-2,232 protein-coding genes. These strains possessed a plasmid similar to pSci6 from the GII3-3X strain associated with leafhopper transmission. Prophage sequences found in the S. citri genomes may contribute to the extension of its host range. These findings increase our understanding of S. citri genetic diversity.

scholarly journals Novel Diagnosis for Citrus Stubborn Disease by Detection of a Spiroplasma citri-Secreted Protein

2014 ◽  
Vol 104 (2) ◽  
pp. 188-195 ◽  
Author(s):  
Jinxia Shi ◽  
Deborah Pagliaccia ◽  
Robyn Morgan ◽  
Yongli Qiao ◽  
Songqin Pan ◽  
...  
Keyword(s):  
The United States ◽  
Fruit Production ◽  
Plant Diseases ◽  
Microbial Pathogens ◽  
Mass Spectrometry Analysis ◽  
Bacterial Disease ◽  
Secreted Protein ◽  
Spiroplasma Citri ◽  
Spectrometry Analysis ◽  
Citrus Stubborn Disease

Citrus stubborn disease (CSD), first identified in California, is a widespread bacterial disease found in most arid citrus-producing regions in the United States and the Mediterranean Region. The disease is caused by Spiroplasma citri, an insect-transmitted and phloem-colonizing bacterium. CSD causes significant tree damage resulting in loss of fruit production and quality. Detection of CSD is challenging due to low and fluctuating titer and sporadic distribution of the pathogen in infected trees. In this study, we report the development of a novel diagnostic method for CSD using an S. citri-secreted protein as the detection marker. Microbial pathogens secrete a variety of proteins during infection that can potentially disperse systemically in infected plants with the vascular flow. Therefore, their distribution may not be restricted to the pathogen infection sites and could be used as a biological marker for infection. Using mass spectrometry analysis, we identified a unique secreted protein from S. citri that is highly expressed in the presence of citrus phloem extract. ScCCPP1, an antibody generated against this protein, was able to distinguish S. citri-infected citrus and periwinkle from healthy plants. In addition, the antiserum could be used to detect CSD using a simple direct tissue print assay without the need for sample processing or specialized lab equipment and may be suitable for field surveys. This study provides proof of a novel concept of using pathogen-secreted protein as a marker for diagnosis of a citrus bacterial disease and can probably be applied to other plant diseases.

scholarly journals Citrus Stubborn Disease: Current Insights on an Enigmatic Problem Prevailing in Citrus Orchards

2022 ◽  
Vol 10 (1) ◽  
pp. 183
Author(s):  
Tourya Sagouti ◽  
Zineb Belabess ◽  
Naima Rhallabi ◽  
Essaid Ait Barka ◽  
Abdessalem Tahiri ◽  
...  
Keyword(s):  
Pathogen Detection ◽  
Primary Source ◽  
Poor Quality ◽  
Disease Spread ◽  
Spiroplasma Citri ◽  
A Genome ◽  
A Cell ◽  
Citrus Orchards ◽  
A Minor ◽  
Citrus Stubborn Disease

Citrus stubborn was initially observed in California in 1915 and was later proven as a graft-transmissible disease in 1942. In the field, diseased citrus trees have compressed and stunted appearances, and yield poor-quality fruits with little market value. The disease is caused by Spiroplasma citri, a phloem-restricted pathogenic mollicute, which belongs to the Spiroplasmataceae family (Mollicutes). S. citri has the largest genome of any Mollicutes investigated, with a genome size of roughly 1780 Kbp. It is a helical, motile mollicute that lacks a cell wall and peptidoglycan. Several quick and sensitive molecular-based and immuno-enzymatic pathogen detection technologies are available. Infected weeds are the primary source of transmission to citrus, with only a minor percentage of transmission from infected citrus to citrus. Several phloem-feeding leafhopper species (Cicadellidae, Hemiptera) support the natural spread of S. citri in a persistent, propagative manner. S. citri-free buds are used in new orchard plantings and bud certification, and indexing initiatives have been launched. Further, a quarantine system for newly introduced types has been implemented to limit citrus stubborn disease (CSD). The present state of knowledge about CSD around the world is summarized in this overview, where recent advances in S. citri detection, characterization, control and eradication were highlighted to prevent or limit disease spread through the adoption of best practices.

scholarly journals Polymerase Chain Reaction-Based Detection of Spiroplasma citri Associated with Citrus Stubborn Disease

Plant Disease ◽  
2008 ◽  
Vol 92 (2) ◽  
pp. 253-260 ◽  
Author(s):  
Raymond K. Yokomi ◽  
Alexandre F. S. Mello ◽  
Maria Saponari ◽  
Jacqueline Fletcher
Keyword(s):  
Polymerase Chain Reaction ◽  
Real Time ◽  
Real Time Pcr ◽  
Disease Incidence ◽  
Chain Reaction ◽  
Spiroplasma Citri ◽  
Field Samples ◽  
Polymerase Chain ◽  
Individual Trees ◽  
Citrus Stubborn Disease

Polymerase chain reaction (PCR)-based detection of citrus stubborn disease was improved using primers based on sequences of the P89 putative adhesin gene and the P58 putative adhesin multigene of Spiroplasma citri. Real-time PCR also was developed with detection limits estimated to be between 10–4 and 10–4 ng by serial dilution of a recombinant S. citri plasmid into DNA extracts from healthy Madam Vinous sweet orange. PCR for the detection of S. citri by these new primers was validated by comparing culturing of the pathogen, the traditional method of diagnosis, with PCR assays from samples taken from two citrus plots in Kern County, CA. Fruit columella was collected from 384 and 377 individual trees in each of two fields, respectively; one portion was used for culturing and the other for DNA extraction and PCR. PCR results matched those of culturing 85 to 100% of the time depending on the primers used. More importantly, PCR detected S. citri from culture-negative trees in 5 to 15% of the cases, suggesting that PCR performed as well or better than culturing for detection of S. citri in field samples. Real-time PCR proved to be the best method for detection. Differential reaction of the samples to the P58 primer pairs suggested that two populations of S. citri occur in historical and present-day field isolates. Citrus stubborn disease incidence was estimated to be 58.3 and 3.7% in the two orchards. The results presented here support the use of PCR for reliable detection of S. citri in field trees.

scholarly journals Genome Analysis of Spiroplasma Citri Strains From Different Host Plants and Its Leafhopper Vectors

2020 ◽  
Author(s):  
Rachel Rattner ◽  
Shree Prasad Thapa ◽  
Tyler Dang ◽  
Fatima Osman ◽  
Vijayanandraj Selvaraj ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Host Range ◽  
Genetic Relationships ◽  
Phylogenetic Analyses ◽  
The United States ◽  
Weed Species ◽  
Protein Coding ◽  
Spiroplasma Citri ◽  
Beet Leafhopper ◽  
Separate Branch

Abstract Background Spiroplasma citri comprises a complex of bacteria that cause diseases in citrus, horseradish, carrot, sesame, and also infect a wide array of ornamental and weed species. S. citri is transmitted in a persistent propagative manner by the beet leafhopper, Neoaliturus tenellus in North America and Circulifer haematoceps in the Mediterranean region. Leafhopper transmission and the pathogen’s wide host range serve as drivers of genetic diversity. This diversity was examined by comparing the genome sequences of seven S. citri strains from the United States (BR12, CC2, C5, C189, LB319, BLH-13, and BLH-MB) collected from different hosts and times with other publicly available spiroplasmas.Results Phylogenetic analysis using 16S rRNA sequences from 39 spiroplasmas obtained from NCBI database showed that S. citri strains, along with S. kunkelii and S. phoeniceum, two other plant pathogenic spiroplasmas, formed a monophyletic group. To refine genetic relationships among S. citri strains, phylogenetic analyses with 863 core orthologous sequences were performed. Strains that clustered together were: CC-12 and C5; C189 and R8-A2; BR12, BLH-MB, BLH13 and LB 319. Strain GII3-3 remained in a separate branch. Sequence rearrangements were observed among S. citri strains, predominantly in the center of the chromosome. One to nine plasmids were identified in the seven S. citri strains analyzed in this study. Plasmids were most abundant in strains isolated from the beet leafhopper, followed by strains from carrot, Chinese cabbage, horseradish and citrus, respectively. All these S. citri strains contained one plasmid with high similarity to plasmid pSci6 from S. citri strain GII3-3X which is known to confer insect transmissibility. Additionally, 17 to 25 prophage-like elements were identified in these genomes, which may promote rearrangements and contribute to repetitive regions. Conclusions The genome of seven S. citri strains were found to contain a single circularized chromosome, ranging from 1.58 Mbp to 1.74 Mbp and 1,597-2,232 protein-coding genes. These strains possessed a plasmid similar to pSci6 from the GII3-3X strain associated with leafhopper transmission. Prophage sequences found in the S. citri genomes may contribute to the extension of its host range. These findings increase our understanding of S. citri genetic diversity.

scholarly journals Development of a Co-Dominant Cleaved Amplified Polymorphic Sequences Assay for the Rapid Detection and Differentiation of Two Pathogenic Clarireedia spp. Associated with Dollar Spot in Turfgrass

Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1489
Author(s):  
Tammy Stackhouse ◽  
Sumyya Waliullah ◽  
Alfredo D. Martinez-Espinoza ◽  
Bochra Bahri ◽  
Emran Ali
Keyword(s):  
Pcr Primers ◽  
The United States ◽  
Fungal Species ◽  
Dollar Spot ◽  
Direct Pcr ◽  
Specific Pcr ◽  
Specificity And Sensitivity ◽  
Pure Cultures ◽  
Speed Up ◽  
Cleaved Amplified Polymorphic Sequences

Dollar spot is one of the most destructive diseases in turfgrass. The causal agents belong to the genus Clarireedia, which are known for causing necrotic, sunken spots in turfgrass that coalesce into large damaged areas. In low tolerance settings like turfgrass, it is of vital importance to rapidly detect and identify the pathogens. There are a few methods available to identify the genus Clarireedia, but none of those are rapid enough and characterize down to the species level. This study produced a co-dominant cleaved amplified polymorphic sequences (CAPS) test that differentiates between C. jacksonii and C. monteithiana, the two species that cause dollar spot disease within the United States. The calmodulin gene (CaM) was targeted to generate Clarireedia spp. specific PCR primers. The CAPS assay was optimized and tested for specificity and sensitivity using DNA extracted from pure cultures of two Clarireedia spp. and other closely related fungal species. The results showed that the newly developed primer set could amplify both species and was highly sensitive as it detected DNA concentrations as low as 0.005 ng/µL. The assay was further validated using direct PCR to speed up the diagnosis process. This drastically reduces the time needed to identify the dollar spot pathogens. The resulting assay could be used throughout turfgrass settings for a rapid and precise identification method in the US.

scholarly journals Development of a Protocol and a Diagrammatic Scale for Quantification of Bacterial Leaf Streak Disease on Young Plants of Maize

Plant Disease ◽  
2020 ◽  
Vol 104 (11) ◽  
pp. 2921-2927
Author(s):  
Renata Rodrigues Robaina ◽  
Talita Vigo Longhi ◽  
Douglas Mariani Zeffa ◽  
Leandro Simões Azeredo Gonçalves ◽  
Rui Pereira Leite
Keyword(s):  
Disease Incidence ◽  
The United States ◽  
Bacterial Suspension ◽  
Bacterial Leaf Streak ◽  
Experimental Conditions ◽  
Maize Production ◽  
Maize Hybrids ◽  
Controlled Conditions ◽  
Maize Plants ◽  
Diagrammatic Scale

Bacterial leaf streak (BLS), caused Xanthomonas vasicola pv. vasculorum (Xvv), has become a major concern for maize production, mainly in the United States and South America. Therefore, this study aimed to establish a protocol for Xvv inoculation in young maize plants under controlled conditions and to develop and validate a diagrammatic scale for evaluation of maize hybrids in regard to BLS resistance. The study was carried out in three steps: the establishment of a protocol for inoculation of Xvv in young maize plants under controlled conditions; the development and validation of a diagrammatic scale for BLS severity evaluation; and the screening for BLS resistance of 45 hybrids using the proposed protocol for bacterial inoculation and the diagrammatic scale developed in this study. Besides reproducing a more natural Xvv infection, the bacterial suspension spraying without injury inoculation method induced higher disease incidence and severity, as well as reproducibility of results under the experimental conditions established in this study. The proposed diagrammatic scale allowed evaluating BLS severity with up to 97.49% of the leaf area affected by the disease. Further, the use of the diagrammatic scale resulted in an increase of accuracy from 0.909 up to 0.992. The reaction of 45 maize hybrids to BLS allowed establishing six major groups of susceptibility to the disease. The most resistant maize hybrids to BLS formed a group of 13 hybrids, with disease severity below 5%.

scholarly journals Molecular Analysis of a Plum pox virus W Isolate in Plum Germplasm Hand Carried into the USA from the Ukraine Shows a Close Relationship to a Latvian Isolate

Plant Disease ◽  
2013 ◽  
Vol 97 (1) ◽  
pp. 44-52 ◽  
Author(s):  
Vessela Mavrodieva ◽  
Delano James ◽  
Karen Williams ◽  
Sarika Negi ◽  
Aniko Varga ◽  
...  
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
The United States ◽  
Common Source ◽  
Plum Pox Virus ◽  
High Genetic Diversity ◽  
Close Relationship ◽  
The Usa ◽  
Sequence Identities ◽  
Germplasm Accessions

Four of 19 Prunus germplasm accessions hand carried from the Ukraine into the United States without authorization were found to be infected with Plum pox virus (PPV). Of the three isolates characterized, isolates UKR 44189 and UKR 44191 were confirmed to be isolates of PPV strain W, and UKR 44188 was confirmed to be an isolate of PPV strain D. UKR 44189 and UKR 44191 are very closely related to the PPV strain W isolate LV-145bt (HQ670748) from Latvia. Nucleotide and amino acid sequence identities between these three isolates were greater than 99%. This indicates that the isolates are very closely related and likely originated from a common source. The high genetic diversity among PPV-W strain isolates allowed the identification of potential recombination events between PPV isolates. It appears also that GF 305 peach and Prunus tomentosa are not hosts for the PPV isolate UKR 44189.

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