Publications (2705)

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Update and validation of the 16S rDNA qPCR assay for the detection of three ‘Candidatus’ Liberibacter species following current MIQE guidelines and workflow

Citation
Osman et al. (2022). PhytoFrontiers™
Names
Ca. Liberibacter asiaticus Liberibacter
Subjects
General Medicine
Abstract
An updated real-time multiplex quantitative polymerase chain reaction (qPCR) assay was designed and validated for the simultaneous detection of three ‘Candidatus Liberibacter species’ (CLsp), Ca. Liberibacter asiaticus (CLas), africanus (CLaf) and americanus (CLam), associated with the Huanglongbing (HLB) disease of citrus. The multiplex assay was designed based on the previously published qPCR assay by Li et al., 2006, taking into consideration all available CLsp 16S rRNA gene sequences in the GenBank and the MIQE guidelines and workflow for qPCR optimization, which became available after 2006. When using the updated multiplex CLsp qPCR assay compared to singleplex qPCR, no significant increase in Cq values was detected. The specificity and sensitivity of the updated qPCR assay was optimal and measuring the intra and inter assay variations confirmed the reproducibility and repeatability of the assay. The assay was also successfully used with a large number of diverse samples, at independent laboratories in four countries, thus demonstrating its transferability, applicability, practicability, and robustness as different qPCR reaction conditions or instruments had a minor effect on Cq values. This updated multiplex CLsp qPCR assay can be used in a variety of citrus surveys, germplasm, or nursery stock programs that require different pathogen detection tools for their successful operation. Keywords: Citrus greening disease, COX internal DNA control; validation; citrus germplasm; budwood; citrus nursery, citrus survey, regulatory diagnostics, Citrus Clonal Protection Program (CCPP), National Clean Plant Network (NCPN)

Epidemiological Role of Dictyophara europaea (Hemiptera: Dictyopharidae) in the Transmission of ‘Candidatus Phytoplasma solani’

Citation
Cvrković et al. (2022). Horticulturae 8 (7)
Names
Ca. Phytoplasma solani
Subjects
Horticulture Plant Science
Abstract
Bois noir, an economically important disease of grapevine yellows that causes significant economic losses in wine production, is associated with ‘Candidatus Phytoplasma solani’ and transmitted to grapevines by cixiids Hyalesthes obsoletus and Reptalus panzeri. Polyphagous planthopper Dictyophara europaea, commonly found in natural habitats, harbors phytoplasmas from distinct groups and is an alternative vector in the open epidemiological cycles of the Flavescence dorée phytoplasma in grapevine in European vineyards. This study addresses the role of D. europaea in the transmission cycle(s) of ‘Ca. P. solani’ among wild habitats, natural reservoir plants, and the vineyard agroecosystem using MLSA and transmission trials with naturally infected adults to grapevine and Catharanthus roseus. The infection rates of D. europaea ranged from 7% to 13% in diverse locations, while reservoir herbaceous plants were infected in the amount of 29%. A total of 13 CaPsol MLSA genotypes were detected in D. europaea (7) and plants (8). Nine of them corresponded to previously identified genotypes. Two new genotypes were found in D. europaea (tuf-b1/S1/V14/Rqg50-sv1 and tuf-b1/S18/V14/Rqg50-sv1) and one in Convolvulus arvensis (tuf-b1/S1/V2-TA/Rqg31-sv1), whereas one was shared by two hosts, Crepis foetida and Daucus carota (tuf-b1/S1/V2-TA/STOL-sv1). Naturally infected D. europaea successfully transmitted the tuf-b1/S1/V2-TA/STOL type to five grapevines and six periwinkles, tuf-b1/S1/V2-TA/Rqg31 to one grapevine, and tuf-b1/S1/V2-TA/Rqg50 to one periwinkle, indicating that D. europaea is an intermediate vector in CaPsol epidemiological cycles.

Beyond Destabilizing Activity of SAP11-like Effector of Candidatus Phytoplasma mali Strain PM19

Citation
Boonrod et al. (2022). Microorganisms 10 (7)
Names
Ca. Phytoplasma mali
Subjects
Microbiology Microbiology (medical) Virology
Abstract
It was shown that the SAP11 effector of different Candidatus Phytoplasma can destabilize some TEOSINE BRANCHES/CYCLOIDEA/PROLIFERATING CELL FACTORs (TCPs), resulting in plant phenotypes such as witches’ broom and crinkled leaves. Some SAP11 exclusively localize in the nucleus, while the others localize in the cytoplasm and the nucleus. The SAP11-like effector of Candidatus Phytoplasma mali strain PM19 (SAP11PM19) localizes in both compartments of plant cells. We show here that SAP11PM19 can destabilize TCPs in both the nucleus and the cytoplasm. However, expression of SAP11PM19 exclusively in the nucleus resulted in the disappearance of leaf phenotypes while still showing the witches’ broom phenotype. Moreover, we show that SAP11PM19 can not only destabilize TCPs but also relocalizes these proteins in the nucleus. Interestingly, three different transgenic Nicotiana species expressing SAP11PM19 show all the same witches’ broom phenotype but different leaf phenotypes. A possible mechanism of SAP11-TCP interaction is discussed.

Fluctuación poblacional de Bactericera cockerelli Sulcer e incidencia de Candidatus Liberibacter Solanacearun en papa, Jinotega 2014

Citation
Jiménez-Martínez, Moncada Casco (2022). Revista Universitaria del Caribe 28 (01)
Names
Liberibacter
Subjects
General Economics, Econometrics and Finance
Abstract
El cultivo de papa representa en nuestro país una fuente de divisas y genera gran cantidad de empleos. Hasta la fecha no existe un estudio formal sobre la fluctuación poblacional de Bactericera cockerelli y Candidatus liberibacter. Este estudio se realizó con el propósito de determinar la dinámica poblacional de Bactericera cockerelli y la incidencia de Candidatus liberibacter en papa, el cual se llevó a cabo en los municipios Jinotega, La Concordia, San Rafael del Norte y Yalí, del departamento de Jinotega, en el periodo comprendido de febrero a septiembre del 2014.  El levantamiento de datos se desarrolló en 4 fincas de papa. En cada finca se ubicaron 30 trampas amarillas pegajosas y 30 estaciones para el muestreo visual. Los insectos Bactericera cockerelli encontrados, así como los síntomas de la enfermedad detectados en campo, se identificaron con ayuda de la guía temática utilizada por los especialistas fitosanitarios del Instituto de Protección y Sanidad Agropecuaria (IPSA). Se evaluó el número de insectos capturados en las trampas amarillas y el númede insectos observados, el número de plantas con síntomas de Candidatus liberibacter y la incidencia de daño en tubérculos en las fincas de papa. De acuerdo a los resultados obtenidos se demostró que las poblaciones de Bactericera cockerelli se presentaron en papa, desde marzo 14 hasta mayo 23, con el máximo pico poblacional abril 25, en el ciclo de primera y de junio 23 hasta septiembre 02, con el máximo pico poblacional en julio 22, en el ciclo de postrera; la incidencia de Candidatus liberibacter en papa fue mayor en el ciclo de primera que en postrera y la incidencia de Candidatus liberibacter en tubérculos fue mayor en la finca Buenos Aires con 72%, El Aguacate 1 presentó 32%, Las Piedras 23% y El Aguacate 2, 16%.