Distribution and molecularcharacterization of Citrus yellow vein clearing virus in Yunnan Province of China

Citrus yellow vein clearing virus is a new member of the genus Mandarivirus in the family Alphaflexiviridae. Citrus yellow vein clearing virus (CYVCV) is the causal agent of citrus yellow vein clearing disease and is widely distributed in Pakistan, India, Turkey, and China. CYVCV is transmitted from citrus to citrus by Dialeurodes citri, grafting, and contaminated knife blades, threatening citrus production. In this study, four infectious full-length cDNA clones of CYVCV (namely AY112, AY132, AY212, and AY221) derived from CYVCV isolate AY were obtained through yeast homologous recombination and inoculated to ‘Eureka’ lemon (Citrus limon Burm. f.) by Agrobacterium-mediated vacuum infiltration. Pathogenicity analysis indicated that the clones AY212 and AY221 caused more severe symptoms than AY112 and AY132. Northern blot and quantitative reverse transcription PCR (qRT-PCR) analyses showed that the titers of virulent clones (AY212 and AY221) were significantly higher than those of attenuated clones (AY112 and AY132) in the infected ‘Eureka’ lemon (Citrus limon Burm. f.) seedlings. Subsequent comparative studies of viral infectivity, accumulation, and symptoms induced by AY221 in nine citrus cultivars indicated that (i) the infectivity of AY221 varied from 25% to 100% among different cultivars; (ii) ‘Oota’ ponkan (C. reticulata L.) showed the lowest infection rate with mild symptoms, which might be a useful resource for CYVCY-resistance genes; (iii) CYVCV titer was positively associated with the symptom development in infected citrus seedlings. In general, this report revealed the biological properties of CYVCV, thus laying a foundation for further investigation of pathogenic mechanisms in this virus.

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First Report of Beet necrotic yellow vein virus Infecting Spinach in California

Plant Disease ◽

10.1094/pdis-94-5-0640a ◽

2010 ◽

Vol 94 (5) ◽

pp. 640-640 ◽

Cited By ~ 4

Author(s):

H.-Y. Liu ◽

B. Mou ◽

K. Richardson ◽

S. T. Koike

Keyword(s):

Spinacia Oleracea ◽

Sandwich Elisa ◽

Chenopodium Quinoa ◽

Yellow Vein ◽

Mechanical Transmission ◽

Polymyxa Betae ◽

Rt Pcr ◽

First Report ◽

Vein Clearing ◽

Rigid Rod

In 2009, plants from two spinach (Spinacia oleracea) experimental fields in Monterey County and one commercial spinach field in Ventura County of California exhibited vein-clearing, mottling, interveinal yellowing, and stunting symptoms. For experimental fields, up to 44% of spinach plants have symptoms. With a transmission electron microscope, rigid rod-shaped particles with central canals were observed from plant sap of the symptomatic spinach. Analysis with a double-antibody sandwich-ELISA assay for Beet necrotic yellow vein virus (BNYVV) showed that all 10 symptomatic plants we tested were positive and 5 asymptomatic plants were negative. Symptomatic spinach from both counties was used for mechanical transmission experiments. Chenopodium quinoa, Tetragonia expansa, and Beta vulgaris (sugar beet) showed chlorotic local lesions and B. macrocarpa and spinach showed vein-clearing, mottling, and systemic infections. To further confirm the presence of BNYVV, reverse transcription (RT)-PCR was conducted. Total RNA was extracted from field- and mechanically inoculated symptomatic spinach plants using an RNeasy Plant Kit (Qiagen Inc., Valencia, CA) and used as a template in RT-PCR. Forward and reverse primers specific to the BNYVV RNA-3 P25 protein gene from the beet isolate were used (2). Amplicons of the expected size (approximately 860 bp) were obtained. Four RT-PCR products were sequenced and the sequences were identical (GenBank Accession No. GU135626). Sequences from the spinach plants had 97 to 99% nucleotide and 94 to 100% amino acid identity with BNYVV RNA-3 P25 protein sequences available in the GenBank. On the basis of the data from electron microscopy, indicator plants, serology, and cDNA sequencing, the virus was identified as BNYVV. BNYVV has been reported from spinach fields in Italy (1). To our knowledge, this is the first report of BNYVV occurring naturally on spinach in California. Since BNYVV is transmitted by the zoospores of the soil-inhabiting plasmodiophorid Polymyxa betae, it could be a new threat to spinach production in the state. References: (1) C. R. Autonell et al. Inf. Fitopatol. 45:43, 1995. (2) H.-Y. Liu and R. T. Lewellen, Plant Dis. 91:847, 2007.

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Identification of Dialeurodes citri as a Vector of Citrus yellow vein clearing virus in China

Plant Disease ◽

10.1094/pdis-05-18-0911-re ◽

2019 ◽

Vol 103 (1) ◽

pp. 65-68 ◽

Cited By ~ 6

Author(s):

Y. H. Zhang ◽

C. H. Liu ◽

Q. Wang ◽

Y. L. Wang ◽

C. Y. Zhou ◽

...

Keyword(s):

Viral Disease ◽

Yellow Vein ◽

Sour Orange ◽

Rt Pcr ◽

Panonychus Citri ◽

Vein Clearing ◽

Access Period ◽

Inoculation Access Period ◽

Dialeurodes Citri ◽

The Mean

In 2009, a new citrus viral disease caused by Citrus yellow vein clearing virus (CYVCV) was first discovered in China and now CYVCV is widely distributed in the field. CYVCV is transmissible by grafting and is spread by aphids from lemon to bean, and from bean to bean. However, until now, no vector has been shown to transmit CYVCV from citrus to citrus. In this study, after a 24-h acquisition access period (AAP), CYVCV was tested for in Dialeurodes citri (Ashmead), Panonychus citri McGregor, and Aphis citricidus (Kirkaldy) by quantitative RT-PCR. After an AAP of 48 h, groups of adults of D. citri, P. citri, and A. citricidus were given a 48 h inoculation access period on cultivar Daidai sour orange seedlings. Three, 6, and 12 months post-transmission by D. citri, CYVCV was detected in the receptor plants, and the mean incidence of infected trees was 31.9, 39.1, and 39.1%, respectively. CYVCV was not transmitted to citrus by P. citri or A. citricidus. This is the first report of the ability of D. citri to transmit CYVCV from infected to healthy citrus under laboratory conditions.

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Molecular Variation of Satellite DNAβ Molecules Associated with Malvastrum yellow vein virus and Their Role in Pathogenicity

Applied and Environmental Microbiology ◽

10.1128/aem.02461-07 ◽

2008 ◽

Vol 74 (6) ◽

pp. 1909-1913 ◽

Cited By ~ 23

Author(s):

Wei Guo ◽

Tong Jiang ◽

Xian Zhang ◽

Guixin Li ◽

Xueping Zhou

Keyword(s):

Petunia Hybrida ◽

Yunnan Province ◽

Geographical Origin ◽

Geographical Location ◽

Yellow Vein ◽

Molecular Variation ◽

Infectious Clones ◽

Malvastrum Coromandelianum ◽

Geographical Locations ◽

Limited Sequence

ABSTRACT Previous studies have found that the diversity of begomovirus-associated DNAβ satellites is related to host and geographical origin. In this study, we have cloned and sequenced 20 different isolates of DNAβ molecules associated with Malvastrum yellow vein virus (MYVV) isolated from Malvastrum coromandelianum plants in different geographical locations of Yunnan Province, China. Analyses of their molecular variation indicate that the satellites are clustered together according to their geographical location but that they have only limited sequence diversity. Infectivity tests using infectious clones of MYVV and its associated DNAβ molecule indicate that MYVV DNAβ is indispensable for symptom induction in Nicotiana benthamiana, N. glutinosa, Petunia hybrida, and M. coromandelianum plants. Furthermore, we showed that MYVV interacts functionally with heterologous DNAβ molecules in N. benthamiana plants.

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