Molecular and biological characterization of natural variants of Citrus dwarfing viroid

Murcia, N.; Bernad, Lucía; Serra, Pedro; Hashemian, S. M. Bani; Duran-Vila, N.

doi:10.1007/s00705-009-0430-9

Cited by 16 publications

(10 citation statements)

References 19 publications

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“…consequence of a low genetic variability of this viroid species, as also observed by Owens et al (1999), Murcia et al (2009) and Eiras et al (2010). We did not observe any differences on symptoms in the plants single (Nav1) or doubly infected (Nav5 and Nav6) by HSVd and CDVd.…”

supporting

confidence: 53%

“…CEVd and HSVd are the causal agents of two wellknown citrus viroid diseases, exocortis and cachexia (or xyloporosis), respectively. Although some citrus infecting viroids, as CBLVd and CDVd, do not incite conspicuous symptoms, they can reduce tree size and crop yield (Murcia et al, 2009;Vernière et al, 2006). The control of viroids is based on prevention measures, using viroid-free bud-wood as propagation material, appropriate sanitation, treatment of cutting tools and adequate indexing procedures (Duran-Vila & Semancik, 2003;Eiras et al, 2009).…”

mentioning

confidence: 99%

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Identification and characterization of viroids in 'Navelina ISA 315' sweet orange

Eiras

Silva

Stuchi

et al. 2013

Trop. plant pathol.

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To date, seven species of viroids have been described infecting Citrus. However, only Citrus exocortis viroid (CEVd), Hop stunt viroid (HSVd) and Citrus dwarfing viroid (CDVd) have been reported in this crop in Brazil. The aim of our work was to identify and characterize viroids infecting plants of 'Navelina ISA 315' sweet orange cultivar grafted on 'Rangpur' lime from field experiments located in Bebedouro, SP, that showed gumming in the bark and wood symptoms. Biological indexing was done on the indicator host 'Clemelin 1120' tangor plants that reacted with typical gumming symptoms. Viroid infection was assessed by graft-inoculation of buds from the field trees on 'Etrog' citron plants grafted on 'Rangpur' lime, followed by RNA extraction and sPAGE analysis. RNAs were subjected to RT-PCR with primers for citrus viroids. The full-length amplified products were sequenced and compared to those available in the GenBank. The trees were found to be infected with cachexia (Ca) variants of HSVd-Ca or HSVd-Ca plus CDVd. The results indicate that efforts have to be made to increase and stimulate the indexing programs, to maintain plants healthy and to develop sanitary programs focused on reducing the spread of viroids and other graft-transmissible agents.

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supporting

confidence: 53%

mentioning

confidence: 99%

Identification and characterization of viroids in 'Navelina ISA 315' sweet orange

Eiras

Silva

Stuchi

et al. 2013

Trop. plant pathol.

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“…Swingle) (CTV bioindicator). Citrus dwarfing viroid (CDVd) (GenBank accession number EU934004), inducing moderate but specific symptoms in etrog citron (4), and CTV (T-305 strain), inducing symptoms in Mexican lime (5), were chosen for this study. To synchronize infection, Volkamer lemon (Citrus volkameriana Ten.…”

mentioning

confidence: 99%

Virus-Viroid Interactions: Citrus Tristeza Virus Enhances the Accumulation of Citrus Dwarfing Viroid in Mexican Lime via Virus-Encoded Silencing Suppressors

Serra

Hashemian

Fagoaga

et al. 2014

J Virol

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An assay to identify interactions between Citrus dwarfing viroid (CDVd) and Citrus tristeza virus (CTV) showed that viroid titer was enhanced by the coinfecting CTV in Mexican lime but not in etrog citron. Since CTV encodes three RNA silencing suppressors (RSSs), p23, p20 and p25, an assay using transgenic Mexican limes expressing each RSS revealed that p23 and, to a lesser extent, p25 recapitulated the effect observed with coinfections of CTV and CDVd. V iroids are infectious, unencapsidated, single-stranded, and highly structured noncoding circular RNAs of 250 to 400 nucleotides (nt). Despite their simplicity, viroids interact with cell factors, which redirect them to replicate and traffic throughout the plant while avoiding the RNA silencing machinery they trigger in their hosts (1).Indexing tests have shown that viroids are widespread in commercial citrus orchards, wherein trees may be coinfected with other graft-transmissible pathogens. Data regarding virus-viroid interactions are very scarce, but the information available indicates that such interactions may alter symptom expression (2, 3). Since coinfection of citrus species with Citrus tristeza virus (CTV) and viroids is not rare, assays were conducted to establish whether interactions between these two types of pathogens actually exist.The assays were performed by comparing single and double infections of the two pathogens in etrog citron (Citrus medica L.) (viroid bioindicator) and Mexican lime (Citrus aurantifolia [Christm.] Swingle) (CTV bioindicator). Citrus dwarfing viroid (CDVd) (GenBank accession number EU934004), inducing moderate but specific symptoms in etrog citron (4), and CTV (T-305 strain), inducing symptoms in Mexican lime (5), were chosen for this study. To synchronize infection, Volkamer lemon (Citrus volkameriana Ten. & Pasq.) seedlings were graft inoculated with CDVd and/or CTV before being used as rootstocks. Etrog citron and Mexican lime were graft propagated to produce groups of five plants for each of the following treatments: (i) plants singly infected with CDVd, (ii) plants singly infected with CTV, (iii) plants coinfected with CTV and CDVd, and (iv) noninfected controls. CTV and CDVd infection was assessed by immunoprinting enzyme-linked immunosorbent assay (ELISA) (6) and dot blot hybridization (7), respectively.After an incubation period of 4 months at 25°C, plant height was measured (Fig. 1) and data were subjected to multifactor analysis of variance (ANOVA). The results indicated that etrog citron singly infected with CTV (P value, 0.00001) or CDVd (P value, 0.05) was stunted, as was Mexican lime singly infected with CTV (P value, 0.0013) but not that with CDVd (P value, 0.98). Height reduction in coinfected plants resulted from the added effect of each pathogen, indicating no interaction between CDVd and CTV in either host (interaction P value for etrog citron, 0.29; interaction P value for Mexican lime, 0.44). Similarly, symptom expression in stems and leaves resulted from the added effect of each pathogen, revealing agai...

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“…The results reported here on the modulation of symptom expression in CEVd‐infected Etrog citron plants show the same trend as those described for PSTVd. It was also observed that CEVd COL ‐infected plants displayed extremely subtle leaf distortion, suggesting that other positions of the viroid molecule may also play a role in the modulation of symptom expression, as already reported for the T L , T R and C domains of PSTVd (Qi and Ding, 2003; Sano et al ., 1992) and for the T L domain of Citrus viroid V (CVd‐V) and Citrus dwarfing viroid (CDVd), two members of the genus Apscaviroid (Murcia et al ., 2009a; Serra et al ., 2009).…”

mentioning

confidence: 99%

Two nucleotide positions in the Citrus exocortis viroid RNA associated with symptom expression in Etrog citron but not in experimental herbaceous hosts

Murcia

Bernad

Duran-Vila

et al. 2010

Molecular Plant Pathology

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Citrus exocortis viroid (CEVd) is the causal agent of exocortis disease of citrus. CEVd has a wide host range that includes woody and herbaceous species. A new CEVd strain (CEVd(COL)), phylogenetically clustering with CEVd variants of Class A inducing severe symptoms in tomato, was identified in Colombia and shown to induce only extremely mild symptoms in Etrog citron indicator plants. Using site-directed mutagenesis, two nucleotide substitutions (314A → G and 315U → A) in the lower strand of the P domain of the predicted CEVd(COL) secondary structure resulted in a severe artificial CEVd(MCOL) variant. Conversely, two nucleotide exchanges (314G → A and 315A → U) in the same region of the severe variant CEVd(E-117) resulted in a symptomless artificial CEVd(ME-117) variant. Infectivity assays conducted with the natural and mutated variants showed that all induced severe symptoms in Gynura aurantiaca, tomato and chrysanthemum. This is the first report of the identification of pathogenic determinants of CEVd in citrus, and shows that these pathogenicity determinants are host dependent.

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Molecular and biological characterization of natural variants of Citrus dwarfing viroid

Cited by 16 publications

References 19 publications

Identification and characterization of viroids in 'Navelina ISA 315' sweet orange

Identification and characterization of viroids in 'Navelina ISA 315' sweet orange

Virus-Viroid Interactions: Citrus Tristeza Virus Enhances the Accumulation of Citrus Dwarfing Viroid in Mexican Lime via Virus-Encoded Silencing Suppressors

Two nucleotide positions in the Citrus exocortis viroid RNA associated with symptom expression in Etrog citron but not in experimental herbaceous hosts

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