commonly known as the greenhouse whitefly, severely infests important crops and serves as a vector for apple scar skin viroid (ASSVd). This vector-mediated transmission may cause the spread of infection to other herbaceous crops. For effective management of ASSVd, it is important to explore the whitefly's proteins, which interact with ASSVd RNA and are thereby involved in its transmission.
View Article and Find Full Text PDF"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.
View Article and Find Full Text PDFSevere 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.
View Article and Find Full Text PDFResistance-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.
View Article and Find Full Text PDFHuanglongbing (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.
View Article and Find Full Text PDFStrain 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).
View Article and Find Full Text PDFA simple and rapid lateral flow immunoassay (LFIA) was developed by utilizing gold nanoparticles conjugated to a polyclonal antibody against coat protein of large cardamom chirke virus (LCCV). The LFIA based on the principle of sandwich immunoassay detected LCCV within ∼10 min and the result could be evaluated visually. The colloidal gold (CG) was made using 1% gold chloride solution.
View Article and Find Full Text PDFDroplet 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.
View Article and Find Full Text PDFMost 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.
View Article and Find Full Text PDFBackground: Aflatoxin contamination of various foodstuffs and agricultural commodities is a major problem worldwide. Several strategies have been reported for the detoxification of aflatoxins in contaminated foods and feeds, but all these methods have their own shortcomings. Traditional medicinal plants are potential sources of aflatoxin-detoxifying compounds.
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