Infection in Lemon Influences Host Preference of the Citrus Whitefly by Affecting the Host Metabolite Composition.

Plant viruses have been known to alter host metabolites that influence the attraction of insect vectors. Our study investigated whether (CYVCV) infection influences vector attractiveness, focusing on the citrus whitefly, (Ashmead). Free choice assays showed that citrus whiteflies exhibited a preference for settling on CYVCV-infected lemon plants versus healthy control plants.

The Discovery of a Hacienda Heights Isolate Diversifies the Geological Origins of the Virus in California, United States.

The citrus yellow vein clearing virus (CYVCV) is an emerging threat to the U.S. citrus industry.

Correction: Sun, Y.-D.; Yokomi, R. Genotype Sequencing and Phylogenetic Analysis Revealed the Origins of Citrus Yellow Vein Clearing Virus California Isolates. 2024, , 188.

In the original publication [...

Genotype Sequencing and Phylogenetic Analysis Revealed the Origins of California Isolates.

The (CYVCV) causes a viral disease that has been reported in some citrus-growing regions in countries in Eurasia including Pakistan, India, Türkiye, Iran, China, and South Korea. Recently, CYVCV was detected in a localized urban area in a town in the middle of California's citrus-growing region and marks the first occurrence of the virus in North America. CYVCV has been reported to be spread by aphid and whitefly vectors and is graft and mechanically transmitted.

Alternative Tissue Sampling for Improved Detection of Liberibacter asiaticus.

Early detection and prompt response are key factors in the eradication of 'huanglongbing' (HLB) in California. Currently, qPCR testing of leaf tissue guides the removal of infected trees. However, because of the uneven distribution of ' Liberibacter asiaticus' (Las) in an infected tree and asymptomatic infection, selecting the best leaves to sample, from a mature tree with more than 200,000 estimated leaves, is a major hurdle for timely detection.

Whole genome sequence of Citrus yellow vein clearing virus CA1 isolate.

Objectives: Citrus yellow vein clearing virus (CYVCV) is an emerging disease that poses a significant threat to the citrus industry in California. In this study, the viral genomic RNA was isolated from Eureka lemon plants in the greenhouse exhibiting CYVCV symptoms. Subsequently, the corresponding DNA genome amplicon was sequenced and annotated.

An Improved Recombinase Polymerase Amplification Coupled with Lateral Flow Assay for Rapid Field Detection of ' Liberibacter asiaticus'.

Huanglongbing (HLB) is a destructive citrus disease that affects citrus production worldwide. ' Liberibacter asiaticus' (Las), a phloem-limited bacterium, is the associated causal agent of HLB. The current standard for detection of Las is real-time quantitative polymerase chain reaction (qPCR) using either the Las 16S rRNA gene or the ribonucleotide reductase (RNR) gene-specific primers/probe.

Amino acid, sugar, phenolic, and terpenoid profiles are capable of distinguishing Citrus tristeza virus infection status in citrus cultivars: Grapefruit, lemon, mandarin, and sweet orange.

Citrus tristeza virus (CTV) is the most severe viral disease for citrus production. Many strains of CTV have been characterized and their symptomology widely varies, ranging from asymptomatic or mild infections to severe symptomology that results in substantial yield loss or host death. The capacity of the different CTV strains to affect the biochemistry of different citrus species has remained largely unstudied, despite that associated metabolomic shifts would be relevant toward symptom development.

Immunocapture-Reverse Transcriptase Loop-Mediated Isothermal Amplification Assay for Detection of Plant RNA Viruses.

Loop-mediated isothermal amplification (LAMP) is a sensitive method that can rapidly amplify a specific nucleic acid target with high specificity. The LAMP reaction process has no denaturation step, instead DNA amplification occurs by strand displacement activity of the Bacillus stearothermophilus (Bst) DNA polymerase under isothermal conditions. It utilizes three sets of forward and reverse oligonucleotide primers specific to six distinct sequences on the target gene.

Detection of Viroids Using RT-qPCR.

Viroids are the smallest known infectious pathogens. They are nonprotein-encoding, single-stranded, circular, naked RNA molecules that can cause several diseases in economically important crops. With the advent of thermal cyclers incorporating fluorescent detection, reverse transcription coupled to the quantitative polymerase chain reaction (RT-qPCR) has transformed the way the viroids are detected.

Multiplex detection of "Candidatus Liberibacter asiaticus" and Spiroplasma citri by qPCR and droplet digital PCR.

"Candidatus Liberibacter asiaticus" (CLas) and Spiroplasma citri are phloem-limited bacteria that infect citrus and are transmitted by insect vectors. S. citri causes citrus stubborn disease (CSD) and is vectored by the beet leafhopper in California.

Spread of Citrus Tristeza Virus in Citrus Orchards in Central California.

In California, citrus tristeza virus (CTV) is regulated by a State Interior Quarantine. In CTV abatement districts in central California, trees with CTV that react to MCA13 (MCA13-positive [MCA13+]), a strain-discriminating monoclonal antibody, are rogued to prevent virus spread. The Tulare County Pest Control District, however, does not participate in this abatement program except for a 1.

A rapid detection tool for VT isolates of Citrus tristeza virus by immunocapture-reverse transcriptase loop-mediated isothermal amplification assay.

Severe strains of Citrus tristeza virus (CTV) cause quick decline and stem pitting resulting in significant economic losses in citrus production. A immunocapture reverse-transcriptase loop-mediated amplification (IC-RT-LAMP) assay was developed in this study to detect the severe VT strains that are typically associated with severe CTV symptoms. The sensitivity of RT-LAMP assay was determined by ten-fold serial dilutions of CA-VT-AT39 RNA, in comparison to one-step RT-droplet digital (dd) PCR.

Identification and Characterization of Resistance-Breaking (RB) Isolates of Citrus tristeza virus.

Resistance-breaking (RB) strains constitute a clade of biological and genetically distinct isolates of Citrus tristeza virus (CTV) that replicate and move systemically in Poncirus trifoliata (trifoliate orange), resistant to other known strains of CTV. Molecular markers have been developed by comparative genome analysis to allow quick identification of potential RB isolates. Here, methods are described to identify and characterize RB strains by reverse transcription-polymerase chain reaction (RT-PCR), quantitative real-time RT-PCR (RT-qPCR), full-length genome sequencing, and biological indexing.

CTV Vectors and Interactions with the Virus and Host Plants.

Citrus is a graft-propagated perennial crop, and Citrus tristeza virus (CTV) is readily graft-transmissible. CTV is comprised of a complex of strains and isolates and, in nature, is spread semi-persistently by aphid vectors. Therefore, citrus trees become infected with multiple CTV strains over time.

Prophage Diversity of 'Candidatus Liberibacter asiaticus' Strains in California.

Huanglongbing (HLB) is a highly destructive citrus disease and is associated with a nonculturable bacterium, 'Candidatus Liberibacter asiaticus'. 'Ca. L.

Nucleotide heterogeneity at the terminal ends of the genomes of two California Citrus tristeza virus strains and their complete genome sequence analysis.

Background: The non-translated regions at the genome ends of RNA viruses serve diverse functions and can exhibit various levels of nucleotide (nt) heterogeneity. However, the extent of nt heterogeneity at the extreme termini of Citrus tristeza virus (CTV) genomes has not been comprehensively documented. This study aimed to characterize two widely prevalent CTV genotypes, T36-CA and T30-CA, from California that have not been sequenced or analyzed substantially.

Development of a duplex droplet digital PCR assay for absolute quantitative detection of "Candidatus Liberibacter asiaticus".

Huanglongbing (HLB, citrus greening) is a devastating citrus disease affecting citrus production worldwide. It is associated with the bacterium "Candidatus Liberibacter asiaticus" (CLas) and is vectored by the Asian citrus psyllid (ACP). Currently, diagnosis of CLas in regulatory samples is based on real-time quantitative polymerase chain reaction (qPCR) using 16S rRNA gene specific primers/probe.

Molecular and biological characterization of a novel mild strain of citrus tristeza virus in California.

Strain differentiating marker profiles of citrus tristeza virus (CTV) isolates from California have shown the presence of multiple genotypes. To better define the genetic diversity involved, full-length genome sequences from four California CTV isolates were determined by small-interfering RNA sequencing. Phylogenetic analysis and nucleotide sequence comparisons differentiated these isolates into the genotypes VT (CA-VT-AT39), T30 (CA-T30-AT4), and a new strain called S1 (CA-S1-L and CA-S1-L65).

Application of droplet digital PCR for quantitative detection of Spiroplasma citri in comparison with real time PCR.

Droplet digital polymerase chain reaction (ddPCR) is a method for performing digital PCR that is based on water-oil emulsion droplet technology. It is a unique approach to measure the absolute copy number of nucleic acid targets without the need of external standards. This study evaluated the applicability of ddPCR as a quantitative detection tool for the Spiroplasma citri, causal agent of citrus stubborn disease (CSD) in citrus.

Identification and Characterization of Citrus tristeza virus Isolates Breaking Resistance in Trifoliate Orange in California.

Most Citrus tristeza virus (CTV) isolates in California are biologically mild and symptomless in commercial cultivars on CTV tolerant rootstocks. However, to better define California CTV isolates showing divergent serological and genetic profiles, selected isolates were subjected to deep sequencing of small RNAs. Full-length sequences were assembled, annotated and trifoliate orange resistance-breaking (RB) isolates of CTV were identified.