First Report of Little cherry virus 2 from Sweet Cherry in Poland

Little cherry disease (LChD) is a serious viral disease of sweet (Prunus avium) and sour (P. cerasus) cherry trees. Infection of sensitive cultivars results in small, angular, and pointed fruits with reduced sweetness. In late summer, leaves show a characteristic red coloration or bronzing of the surfaces. One Ampelovirus species, Little cherry virus 2 (LChV-2) (2), and one unassigned species in the Closteroviridae, Little cherry virus 1 (LChV-1) (3), have been associated with LChD. Twenty-seven sour and sweet cherry trees of six varieties from orchards located in several regions of Poland were tested for LChV-1 and LChV-2. Leaf samples were taken either from trees showing fruit symptoms or from asymptomatic trees during the summer of the 2006 growing season. RNA was isolated from the leaves with an RNeasy Kit (Qiagen, Hilden, CA), and reverse transcription (RT)-PCR was performed using primer pairs LCV1U/LCV1L and LCV2UP2/LCV2LO2, which are specific for a 419-bp fragment of the LChV-1 3′ nontranslated region and a 438-bp fragment of the LChV-2 methyltransferase gene, respectively (1). The primer pair L2CPF (5′-GTTCGAAAGTGTTTCTTGAT-3′) and L2CPR (5′-GCAACAGAAAAACATATGACTCA-3′) was designed from existing LChV-2 sequences (GenBank Accession Nos. AF416335 and NC_005065) to amplify the entire LChV-2 coat protein (CP) gene (nucleotides 13,007 to 14,134). The amplified cDNA fragments of LChV-2 genome were ligated to the bacterial vector pCR2.1-TOPO (Invitrogen, Carlsbad, CA), which was used to transform Escherichia coli TOP10 competent cells following the manufacturer's protocol. Both strands of three clones for each amplified LChV-2 genome fragment were sequenced with an automated nucleotide sequencer at the Institute of Biochemistry and Biophysics in Warsaw. RT-PCR results showed that 6 of 27 trees were infected, with LChV-1 detected in five sweet cherry trees and LChV-2 singly infecting one sweet cherry tree cv Elton (isolate C4/14). The nucleotide sequence of the 438-bp methyltransferase gene fragment of isolate C4/14 showed 86, 85, and 84% identity to GenBank Accession Nos. AF333237, AF531505, and AJ430056, respectively, all previously reported LChV-2 sequences from cherry trees. Sequence analysis of the 1,088-bp coat protein gene showed 89 to 91% and 92 to 93% nucleotide and amino acid identity, respectively, with the aforementioned three LChV-2 isolates. The tree infected with LChV-2 was indexed by graft transmission to the woody indicator, Prunus avium cv. Canindex, which showed reddening of the leaves characteristic of LChD 3 months after inoculation. Since cherry production in Poland is 230,000 t per year, the disease may have a significant economic impact because the affected fruits are unsuitable either for consumption or sale. To our knowledge, this is the first report of LChV-2 in Poland. References: (1) M. E. Rott and W. Jelkmann. Phytopathology 91:261, 2001. (2) M. E. Rott and W. Jelkmann. Arch. Virol. 150:107, 2005. (3) M. Vitushkina et al. Eur. J. Plant Pathol. 103:803, 1997.

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First Report of Cherry virus A in Sweet Cherry Trees in China

Plant Disease ◽

10.1094/pdis-93-4-0425b ◽

2009 ◽

Vol 93 (4) ◽

pp. 425-425 ◽

Cited By ~ 4

Author(s):

W.-L. Rao ◽

Z.-K. Zhang ◽

R. Li

Keyword(s):

Sweet Cherry ◽

Community Gardens ◽

Mottle Virus ◽

Replicase Gene ◽

Rt Pcr ◽

First Report ◽

Type Isolate ◽

The Family ◽

Flowering Cherry ◽

Cherry Trees

Plants in the genus Prunus of the family Rosaceae are important fruit and ornamental trees in China. In June of 2007, sweet cherry (Prunus avium) trees with mottling and mosaic symptoms were observed in a private garden near Kunming, Yunnan Province. Twenty-four samples, six each from sweet cherry, sour cherry (P. cerasus), flowering cherry (P. serrulata), and peach (P. persica) were collected from trees in private and community gardens in the area. The peach and sour and flowering cherry trees did not show any symptoms. Total nucleic acids were extracted using a cetyltrimethylammoniumbromide (CTAB) extraction method, and the extracts were tested for the following eight viruses by reverse transcription (RT)-PCR: American plum line pattern virus, Apple chlorotic leaf spot virus, Cherry green ring mottle virus, Cherry necrotic rusty mottle virus, Cherry virus A (CVA), Little cherry virus 1, Prune dwarf virus, and Prunus necrotic ringspot virus. Only CVA was detected in two symptomatic sweet cherry trees by RT-PCR with forward (5′-GTGGCATTCAACTAGCACCTAT-3′) and reverse (5′-TCAGCTGCCTCAGCTTGGC-3′) primers specific to an 873-bp fragment of the CVA replicase gene (2). The CVA infection of the two trees was confirmed by RT-PCR using primers CVA-7097U and CVA-7383L that amplified a 287-bp fragment from the 3′-untranslated region (UTR) of the virus (1). Amplicons from both amplifications were cloned and sequenced. Analysis of the predicted amino acid sequences of the 873-bp fragments (GenBank Accession Nos. EU862278 and EU862279) showed that they were 98% identical with each other and 97 to 98% with the type isolate of CVA from Germany (GenBank Accession No. NC_003689). The 286-bp sequences of the 3′-UTR (GenBank Accession Nos. FJ608982 and FJ608983) were 93% identical with each other and 93 to 98% with the type isolate. The sequence indicated that the three isolates were very similar and should be considered to be the same strain. CVA is a member of the genus Capillovirus in the family Flexiviridae and has been previously reported in Europe, North America, and Japan. The contribution of CVA to the symptoms observed and its distribution in China remain to be evaluated. To our knowledge, this is the first report of CVA in sweet cherry in China. References: (1) M. Isogai et al. J. Gen. Plant Pathol. 70:288. (2) W. Jelkmann. J. Gen. Virol. 76:2015, 1995.

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First Report of Little cherry virus 2 in Flowering and Sweet Cherry Trees in China

Plant Disease ◽

10.1094/pdis-10-10-0766 ◽

2011 ◽

Vol 95 (11) ◽

pp. 1484-1484 ◽

Cited By ~ 4

Author(s):

W.-L. Rao ◽

F. Li ◽

R.-J. Zuo ◽

R. Li

Keyword(s):

Sweet Cherry ◽

Sequence Data ◽

Community Gardens ◽

Economic Losses ◽

Helicase Domain ◽

Rt Pcr ◽

Viral Origin ◽

First Report ◽

Flowering Cherry ◽

Cherry Trees

Many viruses infect Prunus spp. and cause diseases on them. During a survey of stone fruit trees in 2008 and 2009, flowering cherry (Prunus serrulata) and sweet cherry (P. avium) trees with foliar chlorosis and reddening, stem deformity, and tree stunting were observed in private orchards in Anning and Fumin counties of Yunnan Province. Some sweet cherry trees with severe symptoms yielded small and few fruits and had to be removed. Leaf samples were collected from 68 flowering cherry and 30 sweet cherry trees, either symptomatic or asymptomatic, from private orchards and community gardens in Kunming and counties Anning, Chenggong, Fumin, Jinning, Ludian and Yiliang. Total nucleic acids were extracted with a CTAB extraction method and tested by reverse transcription (RT)-PCR assay using virus-specific primers. Little cherry virus 2 (LChV-2), Cherry virus A (CVA), Prunus necrotic ringspot virus (PNRSV), and Prune dwarf virus (PDV) were detected and infection rates were 68.4, 16.3, 9.2, and 7.1%, respectively. Infection of LChV-2 was common in all counties except Ludian where the orchards were healthy. Of 68 infected trees, 29 were found to be infected with LChV-2 and CVA, PDV or PNRSV. LChV-2 was detected in this study by RT-PCR using a pair of novel primers, LCV2-1 (5′-TTCAATATGAGCAGTGTTCCTAAC-3′) and LCV2-4 (5′-ACTCGTCTTGTGACATACCAGTC-3′), in 59 flowering cherry (87%) and 8 sweet cherry (27%) trees, respectively. The primer pair was designed according to alignment of three available LChV-2 sequences (GenBank Nos. NC_005065, AF416335, and AF333237) to amplify the partial RNA-dependent RNA polymerase gene (ORF1b) of 781 bp. The amplicons of selected samples (Anning26 and Yiliang60) were sequenced directly and sequences of 651 bp (GenBank No. HQ412772) were obtained from both samples. Pairwise comparisons and phylogenetic analysis of the sequences show that the two isolates are identical to one another and share 92 to 96% at the amino acid (aa) sequence level to those of other isolates available in the GenBank database. The sequence data confirm that these isolates are a strain of LChV-2 and genetic variation among different strains is relatively high (2). Biological and serological assays are not available for the LChV-2 detection; therefore, the LChV-2 infections of these trees were further confirmed by RT-PCR using primer pair LCV2-5 (5′-TGTTTGTGTCATGTTGTCGGAGAAG-3′) and LCV2-6 (5′-TGAATACCCGAGAACAAGGACTC-3′), which amplified the helicase domain (ORF1a) of ~451 bp. The amplicons from samples Anning26 and Yiliang60 were cloned and sequenced. The 408-bp sequences (excluding primer sequences) were 92 to 98% identical at the aa sequence level to those of other isolates, confirming again their viral origin. LChV-2 (genus Ampelovirus, family Closteroviridae) (4) has been associated with little cherry disease (LChD), a widespread viral disease of sweet and sour cherries (1,3). The virus is transferred between geographic areas mainly by propagated materials. Ornamental and sweet cherries are important crops in China and LChD has the potential to cause significant economic losses. Thus, certified clean stock should be used to establish new orchards. To our knowledge, this is the first report of LChV-2 in cherries in China. References: (1) N. B. Bajet et al. Plant Dis. 92:234, 2008. (2) W. Jelkmann et al. Acta Hortic. 781:321, 2008. (3) B. Komorowska and M. Cieslińska, Plant Dis. 92:1366, 2008. (4) M. E. Rott and W. Jelkmann. Arch. Virol. 150:107, 2005.

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First Report of Little cherry virus 1 Infecting Sweet Cherry in Ontario, Canada

Plant Disease ◽

10.1094/pdis-04-21-0798-pdn ◽

2021 ◽

Author(s):

Aaron Simkovich ◽

Susanne Kohalmi ◽

Aiming Wang

Keyword(s):

San Diego ◽

Sweet Cherry ◽

The United States ◽

Eastern Region ◽

Rt Pcr ◽

Degenerate Primers ◽

Sequence Alignments ◽

First Report ◽

Blastn Search ◽

Cherry Trees

The Niagara fruit belt is one of the richest fruit-producing areas in Canada, contributing to 90% of Ontario's tender fruits such as peach, plum and sweet cherry. Little cherry virus 1 (LCV1) of the genus Velarivirus is a causal agent of little cherry disease which has devastated cherry crops in many regions (Eastwell and Bernardy 1998, Jelkmann and Eastwell, 2011). From 2013 to 2018, foliar symptoms indicative of viral infection such as leaf deformation, ringspot, mottling, vein clearing, and reddening were found on sweet cherry trees grown in the Niagara region. To determine if these trees were infected by a virus, small RNAs (sRNAs) were isolated from separately pooled asymptomatic and symptomatic leaves using the mirPremier microRNA isolation kit (Sigma Aldrich Canada, Oakville, ON). The sRNAs were used to create two libraries (four leaves per library) with the TruSeq Small RNA Sample Prep Kit (Illumina, San Diego, CA). The sRNA libraries were separately sequenced with the MiSeq Desktop Sequencer (Illumina, San Diego, CA). In total, 5,380,196 reads were obtained and Trimmomatic (Bolger et al. 2014) was used to remove adaptors. The remaining 4,733,804 clean reads were assembled into contigs using Velvet 0.7.31 (Zerbino and Birney, 2008) and Oases 0.2.09 (Schulz et al. 2012) with minimum length of 75 nt (Supplementary Table 1). A BLASTn search (Altschul et al. 1997) of the contigs identified the presence of Cherry virus A (genus: Capillovirus), two members of the Ilarvirus genus (Prunus necrotic ringspot virus and Prune dwarf virus) in both libraries. LCV1 was only found in contigs derived from the symptomatic library. Of the clean reads, 22,016 were assembled into six contigs (with lengths ranging from 86 to 116 nt, Supplementary Table 1) mapping to LCV1, covering 7.07% of the viral genome. To confirm LCV1 infection, primers were designed from the assembled contigs and used for reverse transcription polymerase chain reaction (RT-PCR). Amplicons were sequenced and the terminal sequences were determined using 5’ and 3’ RACE Systems (Invitrogen, Burlington, ON). Degenerate primers were designed from multiple sequence alignments of published LCV1 genomes for amplification and primer walking to obtain the sequence of LCV1 (Table S2). The complete genome sequence of LCV1 has a length of 16,934 nt and was deposited in GenBank (accession no. MN508820). A BLASTn search showed that this isolate is nearly identical (99.6% sequence identity) to an isolate from California (accession no. MN131067). To determine the incidence of infection, a field survey was performed at the same location during spring months of 2014 to 2018 using RT-PCR with primers specific to the viral coat protein gene (Supplementary Tale 2). Among 46 cherry trees sampled, two (4.3%) trees were infected with LCV1 and showed negative results with CVA, PNRSV and PDV. Both trees displayed mild suturing of primary and secondary veins (Supplementary Figure 1). LCV1 has been identified in Western stone fruit producing regions (British Columbia in Canada, and Washington, California, and Oregon in the United States of America). To the best of our knowledge, this is the first report of LCV1 in any eastern region of Canada. The low incidence of LCV1 suggests that this virus is not widespread in this region. Routine monitoring and detection of LCV1 is required to prevent this devastating cherry disease from spreading in this region.

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First Report of Transmission of Little cherry virus 2 to Sweet Cherry by Pseudococcus maritimus (Ehrhorn) (Hemiptera: Pseudococcidae)

Plant Disease ◽

10.1094/pdis-12-12-1115-pdn ◽

2013 ◽

Vol 97 (6) ◽

pp. 851-851 ◽

Cited By ~ 15

Author(s):

T. A. Mekuria ◽

T. J. Smith ◽

E. Beers ◽

G. W. Watson ◽

K. C. Eastwell

Keyword(s):

Sweet Cherry ◽

Prunus Avium ◽

Washington State ◽

Replicase Gene ◽

Insect Vector ◽

Significant Finding ◽

Rt Pcr ◽

First Report ◽

Plant Pathol ◽

Pseudococcus Maritimus

Little cherry virus 2 (LChV2; genus Ampelovirus, family Closteroviridae) is associated with Little Cherry Disease (LCD), one of the most economically destructive diseases of sweet cherry (Prunus avium (L.)) in North America (1). Since 2010, incidence of LCD associated with LChV2 confirmed by reverse transcription (RT)-PCR assays has increased in orchards of Washington State. LChV2 was known to be transmitted by the apple mealybug (Phenacoccus aceris (Signoret)) (3). However, the introduction of Allotropus utilis, a parasitoid platygastrid wasp (2) for biological control, contributed to keeping insect populations below the economic threshhold. In recent years, the population of grape mealybug (Pseudococcus maritimus (Ehrhorn)) increased in cherry orchards of Washington State (Beers, personal observation). Since grape mealybug is reported to transmit Grapevine leafroll associated virus 3 (Ampelovirus) in grapevine (4), this study investigated whether this insect would also transmit LChV2. A colony of grape mealybugs on Myrobalan plum (Prunus cerasifera Ehrh.) trees was identified visually and morphologically from slide mounts. In a growth chamber, first and second instar crawlers were fed on fresh cut shoots of sweet cherry infected with a North American strain (LC5) of LChV2. After an acquisition period of 7 days, 50 crawlers were transferred to each young potted sweet cherry trees, cv. Bing, confirmed free from LChV2 by RT-PCR. This process was repeated in two trials to yield a total of 21 potted trees exposed to grape mealybug. One additional tree was left uninfested as a negative control. After 1 week, the trees were treated with pesticide to eliminate the mealybugs. Two to four months after the inoculation period, leaves were collected from each of the recipient trees and tested by RT-PCR for the presence of LChV2. To reduce the possibility of virus contamination from residual mealybug debris on leaf surfaces, the trees were allowed to defoliate naturally. After a 3-month dormant period, the new foliage that emerged was then tested. Two sets of primers: LC26L (GCAGTACGTTCGATAAGAG) and LC26R (AACCACTTGATAGTGTCCT) (1); and LC2.13007F (GTTCGAAAGTGTTTCTTGA) and LC2.14545R (CATTATYTTACTAATGGTATGAC) (this study) were used to amplify a partial segment of the replicase gene (409 bp) and the complete (1,080 bp) coat protein gene of LChV2, respectively. Of 21 trees tested, 18 yielded positive results for LChV2. The reaction products from six randomly selected trees were cloned and the virus identity was verified by sequencing. The sequences of RT-PCR amplicons from both primer pairs showed ≥99% identity to LChV2, strain LC5 (GenBank Accession No. AF416335). The result confirmed that P. maritimus transmits LChV2, a significant finding for this cherry production region. Grape mealybug is of increasing concern in the tree fruit industry because it is difficult to control in established orchards. The presence of infested orchards that serve as reservoirs of both LCD and this insect vector present a challenge for management. To the best of our knowledge this is the first report to show transmission of LChV2 by grape mealybug. References: (1) K. C. Eastwell and M. G. Bernardy. Phytopathology 91:268, 2001. (2) C. F. W. Muesbeck. Can Entomol. 71:158, 1939. (3) J. R. D. Raine et al. Can. J. Plant Pathol. 8:6, 1986. (4) R. Sforza et al. Eur. J. Plant Pathol. 109:975, 2003.

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First Report of Cherry necrotic rusty mottle virus Infecting Sweet Cherry Trees in Korea

Plant Disease ◽

10.1094/pdis-07-13-0723-pdn ◽

2014 ◽

Vol 98 (1) ◽

pp. 164-164 ◽

Cited By ~ 3

Author(s):

I. S. Cho ◽

G. S. Choi ◽

S. K. Choi ◽

E. Y. Seo ◽

H. S. Lim

Keyword(s):

Sweet Cherry ◽

Mottle Virus ◽

Post Inoculation ◽

Rt Pcr ◽

First Report ◽

Coat Protein Region ◽

Pcr Products ◽

Leafroll Virus ◽

Leaf Virus ◽

Cherry Trees

Cherry necrotic rusty mottle virus (CNRMV), an unassigned member in the family Betaflexiviridae, has been reported in sweet cherry in North America, Europe, New Zealand, Japan, China, and Chile. The virus causes brown, angular necrotic spots, shot holes on the leaves, gum blisters, and necrosis of the bark in several cultivars (1). During the 2012 growing season, 154 sweet cherry trees were tested for the presence of CNRMV by RT-PCR. Samples were randomly collected from 11 orchards located in Gyeonggi and Gyeongsang provinces in Korea. RNA was extracted from leaves using the NucliSENS easyMAG system (bioMérieux, Boxtel, The Netherlands). The primer pair CGRMV1/2 (2) was used to amplify the coat protein region of CNRMV. Although none of the collected samples showed any notable symptoms, CNRMV PCR products of the expected size (949 bp) were obtained from three sweet cherry samples from one orchard in Gyeonggi province. The PCR products were cloned into a pGEM-T easy vector (Promega, Madison, WI) and sequenced. BLAST analyses of the three Korean sequences obtained (GenBank Accession Nos. AB822635, AB822636, and AB822637) showed 97% nucleotide sequence identity with a flowering cherry isolate from Japan (EU188439), and shared 98.8 to 99.6% nucleotide and 99.6 to 100% amino acid similarities to each other. The CNRMV positive samples were also tested for Apple chlorotic leaf spot virus (ACLSV), Cherry mottle leaf virus (CMLV), Cherry rasp leaf virus (CRLV), Cherry leafroll virus (CLRV), Cherry virus A (CVA), Little cherry virus 1 (LChV-1), Prune dwarf virus (PDV), and Prunus necrotic ringspot virus (PNRSV) by RT-PCR. One of the three CNRMV-positive samples was also infected with CVA. To confirm CNRMV infection by wood indexing, Prunus serrulata cv. Kwanzan plants were graft-inoculated with chip buds from the CNRMV-positive sweet cherry trees. At 3 to 4 weeks post-inoculation, the Kwanzan plants showed quick decline with leaves wilting and dying; CNRMV infection of the indicators was confirmed by RT-PCR. To our knowledge, this is the first report of CNRMV infection of sweet cherry trees in Korea. Screening for CNRMV in propagation nurseries should minimize spread of this virus within Korea. References: (1) R. Li and R. Mock. Arch. Virol. 153:973, 2008. (2) R. Li and R. Mock. J. Virol. Methods 129:162, 2005.

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The effect of rootstocks on the efficiency of a nursery of sweet cherry (Prunus avium L.) trees cv. ‘Regina’

Acta Agrobotanica ◽

10.5586/aa.2013.058 ◽

2014 ◽

Vol 66 (4) ◽

pp. 121-128

Author(s):

Piotr Baryła ◽

Magdalena Kapłan ◽

Marcela Krawiec ◽

Piotr Kiczorowski

Keyword(s):

Sweet Cherry ◽

Prunus Avium ◽

Cherry Tree ◽

Tree Nursery ◽

Prunus Avium L ◽

Gisela 5 ◽

Cherry Trees

During the period 2006–2009 in Lublin, a study was conducted to determine the effect of five rootstocks: ‘Colt’, ‘F12/1’, sweet cherry (Prunus avium L.), ‘GiSelA 5’, and ‘Piast’, on bud take in the cultivar ‘Regina’, the quality of budded trees and the efficiency of a sweet cherry tree nursery. The highest percentage of bud take in cherry trees cv. ‘Regina’ and the best efficiency of the sweet cherry tree nursery were obtained for the rootstocks ‘Piast’ and ‘Colt’. In two years during the three-year study period, the rootstock was found to significantly affect the efficiency of the sweet cherry tree nursery. When grafted on the rootstocks ‘Colt’ and ‘Piast’, a significantly higher percentage of trees met the requirements of the Polish Standard PN-R-67010 than on the clonal rootstock ‘GiSelA 5’. Under the tested conditions, the quality of maiden sweet cherry trees cv. ‘Regina’ grafted on the dwarfing rootstock ‘GiSelA 5’ was lowest.

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First Report of Cherry necrotic rusty mottle virus on Stone Fruit Trees in China

Plant Disease ◽

10.1094/pdis-09-12-0836-pdn ◽

2013 ◽

Vol 97 (2) ◽

pp. 290-290 ◽

Cited By ~ 6

Author(s):

J. F. Zhou ◽

G. P. Wang ◽

L. N. Qu ◽

C. L. Deng ◽

Y. Wang ◽

...

Keyword(s):

Sweet Cherry ◽

Prunus Persica ◽

Sour Cherry ◽

Fruit Trees ◽

Stone Fruit ◽

Mottle Virus ◽

Rt Pcr ◽

Cherry Tree ◽

First Report ◽

Pcr Products

During the growing seasons of 2010 through 2012, leaf tissues from 206 stone fruit trees, including one flowering cherry, three sour cherry, six nectarine (Prunus persica L. var. nucipersica Schneider), 14 apricot, 24 plum (P. domestica L.), 41 sweet cherry, and 117 peach [P. persica (L.) Batsch] trees, grown in six provinces of China, were randomly collected and tested for the CNRMV infection by RT-PCR. Out of those sampled trees, 37 showed shot holes and vein yellowing symptoms. Total RNA was extracted from leaves using the CTAB protocol reported by Li et al. (2). The primer pair CGRMV1/CGRMV2 (1) was used to amplify a fragment of 949 bp from CNRMV genome, which includes the CP gene (804 bp). PCR products with the expected size were detected in one sweet cherry, one apricot, one peach, one plum, and two sour cherry plants. However, no correlation between PCR data and symptom expression could be found. PCR products were cloned into the vector pMD18-T (TaKaRa, Dalian, China). Three independent clones from each isolate were sequenced by Genscript Corp., Nanjing, China, and sequences were deposited in the GenBank under accession nos. JX491635, JX491636, JX491637, JX648205, and JX648206. Results of sequence analysis showed that sequences of the five CNRMV isolates shared the highest nt (99.0 to 99.6%) and aa (98.9 to 100%) similarities with a cherry isolate from Germany (GenBank Accession No. AF237816). The sequence of one isolate from a peach tree (JX648205) was divergent and shared only 84.7 to 86.1% nt and 94.4 to 95.1% aa similarities with those cp sequences. Clones intra each isolate shared more than 99% nt similarities. To confirm CNRMV infection, seedlings of peach GF 305 were graft-inoculated with bud-woods from a peach and a sweet cherry tree, which was positive to CNRMV and also two other viruses: Cherry green ring mottle virus (CGRMV) and Plum bark necrosis stem pitting-associated virus (PBNSPaV), as tested by RT-PCR. Grafted seedlings were kept in an insectproof greenhouse and observed for symptom development. In May of the following year, some newly developed leaves of inoculated seedlings showed vein yellowing, ringspot, and shot hole symptoms. Results of Protein A sandwich (PAS)-ELISA using an antiserum raised against the recombinant CP of a CNRMV isolate (unpublished) and RT-PCR confirmed CNRMV infection in inoculated trees. In addition to CNRMV, tested seedlings were also found to be infected with CGRMV and PBNSPaV by RT-PCR. To our knowledge, this is the first report on the occurrence of CNRMV on stone fruit trees in China, and also the first record of the CNRMV infection in peach and plum plants. Given the economic importance of its hosts and the visible symptoms of the viral disease, it is important to prevent the virus spread by using virus-tested propagation materials. References: (1) R. Li and R. Mock. J. Virol. Methods 129:162, 2005. (2) R. Li et al. J. Virol. Methods 154:48, 2008.

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First Report of Little Cherry Disease from Sweet Cherry (Prunus avium) and Sour Cherry (P. cerasus) in the Czech Republic

Plant Disease ◽

10.1094/pdis-12-10-0868 ◽

2011 ◽

Vol 95 (9) ◽

pp. 1197-1197 ◽

Cited By ~ 3

Author(s):

H. Ludvíková ◽

J. Suchá

Keyword(s):

Czech Republic ◽

Prunus Avium ◽

Virus Disease ◽

Sour Cherry ◽

Late Summer ◽

Rt Pcr ◽

The Czech Republic ◽

First Report ◽

Young Leaves ◽

Sense Primer

Little cherry disease (LChD), a virus disease of sweet (Prunus avium) and sour cherries (P. cerasus), is caused by members of the Closteroviridae family. Symptoms are especially visible on fruits and leaves. Leaves become red or bronze in late summer and fall. Fruit are small, angular, and pointed. Fruits are unmarketable due to a characteristic bitter flavor. LChD also causes reduction of yield (1). Sweet and sour cherries are the second (after apples) most often grown fruit species in the Czech Republic. Since LChD occurred in Germany (1) and Poland (2) in 2007 and 2008, sweet and sour cherry trees with LChD symptoms were surveyed in orchards in the East Bohemia Region of the Czech Republic. The presence of LChD was determined by reverse transcription (RT)-PCR and woody indicator plants, as recommended by the European and Mediterranean Plant Protection Organization (EPPO). Different parts of plants were taken from trees with suspicious symptoms to observe the dynamics of virus infection during the 2009 growing season. Total RNA was isolated from young leaves, blossoms, fruits, and fully developed leaves with a CONCERT Plant RNA Purification Reagent (Invitrogen, Carlsbad, CA) (3). RT-PCR was performed with a QIAGEN OneStep RT-PCR Kit (Qiagen, Hilden, Germany) and oligonucleotides previously described (4). Oligonucleotide LCV3EC (5′-GCTCTAGAGGCACCTTTTATTTTTTATATATGC-3′), complementary to position 16910 to 16934 (GenBankAccession No. Y10237) (with the addition of eight nonviral nucleotides to introduce an XbaI site), was used as a negative-sense primer in RT reactions and PCR. Oligonucleotide LCV16659 (5′-GTTATAGAATTCACTGCAAGTG-3′) was used as a positive-sense primer for PCR amplification. The program used for cDNA synthesis was 50°C for 30 min, followed by denaturation for 10 min at 95°C, 35 cycles of 45 s at 94°C, 45 s at 58°C, and 45 s at 72°C. A final incubation was at 72°C for 5 min (1). The finished PCR products (430 bp) were analyzed on 1% agarose gels (stained with SYBR green). According to the preliminary results, young leaves from buds (67% of samples of selected trees with LChD were positive), blossoms (67% positive), and leaves taken in autumn (67% positive) were optimal for the detection of LChD by RT-PCR. The trial with woody indicator plant species was established in the field. Indicators P. avium cv. Sam and P. avium cvs. Bing, F12/1, and Canindex (4) were inoculated with buds from LChD-infected trees and observed for 2 years. Woody indicators remained symptomless throughout the first year of observation, but the indicators showed red coloration of leaves in late summer of the second year. P. avium cv. Canindex seems to be the best woody indicator for testing of LChD in the climatic conditions of the Czech Republic. To our knowledge, this is the first report of LChD in the Czech Republic. References: (1) W. Jelkmann et al. Acta Hortic. 781:321, 2008. (2) B. Komorowska and M. Cieślińska. Plant Dis. 92:1366, 2008. (3) J. Matoušek et al. Biol.Chem. 388:1, 2007. (4) M. Vitushkina et al. Eur. J. Plant Pathol. 103:803, 1997.

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First Report of Calosphaeria pulchella Associated with Branch Dieback of Sweet Cherry Trees in California

Plant Disease ◽

10.1094/pdis-94-9-1167a ◽

2010 ◽

Vol 94 (9) ◽

pp. 1167-1167 ◽

Cited By ~ 4

Author(s):

F. P. Trouillas ◽

J. D. Lorber ◽

F. Peduto ◽

J. Grant ◽

W. W. Coates ◽

...

Keyword(s):

Sweet Cherry ◽

Prunus Avium ◽

Large Diameter ◽

The United States ◽

Internal Transcribed Spacer Region ◽

First Report ◽

Agar Plug ◽

Vascular Discoloration ◽

Branch Dieback ◽

Cherry Trees

California is the second largest sweet cherry producer in the United States with approximately 10,800 ha and an average annual crop value of approximately $150 million. Perennial canker diseases constitute major threats to the cherry industry productivity by reducing tree health, longevity, and yields. During the course of summer 2006, we observed severe limb and branch dieback of sweet cherry (Prunus avium L.) in San Joaquin, San Benito, Contra Costa, and Stanislaus counties of California. Isolation from diseased branches repeatedly yielded the fungus Calosphaeria pulchella (Pers.: Fr.) J. Schröt. (1,2). Cankers and vascular necroses had developed in tree limbs and branches, generally initiating from the heart wood and later spreading into the sapwood. External symptoms of disease may be unapparent throughout the early stages of infection, particularly in large diameter shoots. Older infections often appeared as wilted leaves. Branches and trunks affected with cankers from which C. pulchella was isolated also generally bore perithecia of C. pulchella beneath the periderm. Perithecia were nonstromatic and arranged in dense, circinate groups, with elongated necks converging radially and fissuring the periderm. Asci were unitunicate, clavate, and 45 to 55 × 5 to 5.5 μm. Ascospores were allantoid to suballantoid, hyaline, and 5 to 6 × 1 μm. Colonies on potato dextrose agar (PDA) were dark pink to red in their center with a white margin. Conidia were hyaline, allantoid to oblong-ellipsoidal, and (3–) 4 to 6 (–9) × 1.5 to 2 (–2.5) μm. Identification of C. pulchella isolates also was confirmed by sequence comparison in GenBank database using the internal transcribed spacer region (ITS1-5.8S-ITS2) of the rDNA. Sequences of California isolates shared 100% similarity with C. pulchella reference isolate CBS 115999 (EU367451) (2). ITS sequences of the California isolates used in this study were deposited into GenBank (Nos. HM237297 to HM237300). Pathogenicity of four isolates recovered from the margin of active cankers was determined by branch inoculations. In December 2006, 2- to 4-year-old twigs of P. avium cv. Bing were inoculated with a 5-mm cork borer to remove bark and by placing an agar plug from the growing margin of 8-day-old colonies directly into the fresh wound, mycelium side down. Ten branches per isolate were inoculated. Ten control shoots were inoculated with noncolonized agar plugs. Inoculations were covered with vaseline and wrapped with Parafilm to retain moisture. Branches were harvested in July 2007 and taken to the laboratory to be examined for canker development, and the extent of vascular discoloration in each branch was assessed. Isolations from the edge of discolored tissue were conducted to fulfill Koch's postulates. After 8 months, C. pulchella was reisolated from 100% of the inoculated branches. Length of vascular discoloration averaged 62.5 mm in branches inoculated with the four C. pulchella isolates and 16.5 mm in the control twigs. No fungi were reisolated from the slightly discolored tissue of the controls. To our knowledge, this study constitutes the first report of C. pulchella as a pathogen of sweet cherry trees in California. References: (1) M. E. Barr. Mycologia 77:549, 1985. (2) U. Damm et al. Persoonia 20:39, 2008.

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First Report of Calosphaeria pulchella Causing Canker and Branch Dieback of Sweet Cherry Trees in Spain

Plant Disease ◽

10.1094/pdis-01-14-0027-pdn ◽

2014 ◽

Vol 98 (7) ◽

pp. 1008-1008 ◽

Cited By ~ 2

Author(s):

M. Berbegal ◽

J. García-Jiménez ◽

J. Armengol

Keyword(s):

Sweet Cherry ◽

Prunus Avium ◽

South Australia ◽

Economic Loss ◽

Internal Transcribed Spacer Region ◽

First Report ◽

Agar Plug ◽

Query Coverage ◽

Vascular Discoloration ◽

Cherry Trees

In autumn 2012, severe branch cankers and diebacks of sweet cherry trees (Prunus avium L.) were observed in orchards located in two different growing areas in Alicante Province (eastern Spain). In affected trees, leaves become dried without defoliation. Sectorial wood necrosis was also observed, occasionally associated with swollen bark and gum exudates. Isolations were made from diseased branches by surface-disinfecting small fragments of symptomatic tissue in 0.5% NaOCl, double-rinsing in sterile water, and plating them onto potato dextrose agar (PDA) amended with 0.5 g liter−1 of streptomycin sulfate. Plates were incubated at 25°C in the dark for 10 days, and all colonies were transferred to PDA. Pink to red colonies with white margins were consistently isolated. All isolates produced hyaline, allantoid to oblong-ellipsoidal conidia, 4 to 6 × 1.5 to 2 μm. The fungus was identified as Calosphaeria pulchella (Pers.: Fr.) J. Schröt (anamorph Calosphaeriophora pulchella Réblová, L. Mostert, W. Gams & Crous) based on morphology (1). Identification of C. pulchella isolates was confirmed by sequence comparison in GenBank database using the internal transcribed spacer region (ITS1-5.8S-ITS2) of the rDNA. Sequences showed 100% identity and 100% query coverage with C. pulchella reference isolate CBS 115999 (EU367451) (2). The ITS sequence of one of the isolates obtained in this study was deposited into GenBank (KJ396346). Two-year-old sweet cherry trees cv. Burlat were inoculated with two representative C. pulchella isolates from different orchards (1701 and 1702). A 5-mm cork borer was used to remove bark, and an agar plug from the growing margin of 20-day-old colonies was placed directly into the fresh wound, mycelium side down. Five trees were inoculated per isolate (five branches per tree) and 25 control branches were inoculated with non-colonized agar plugs. Inoculated tissue was covered with Vaseline and Parafilm to avoid the loss of water. Branches were taken to the laboratory 9 months after inoculation and thoroughly examined for canker development. The length of vascular discoloration was evaluated in each branch and resulting data were statistically analyzed. Length of vascular discoloration on the inoculated branches (6.6 ± 0.7) was significantly longer than in control plants (2.3 ± 0.3) at P < 0.001. Perithecia were neither observed on the artificially inoculated branches nor in the diseased sweet cherry trees from the sampled orchards. C. pulchella was re-isolated from the inoculated branches and no fungi were isolated from discolored tissue of the controls, confirming Koch's postulates. Canker of sweet cherry caused by C. pulchella is responsible for reducing yields and tree longevity in California and South Australia (3). Cultivated area of sweet cherry in Spain is around 25,000 ha. Hence, the potential economic loss from this pathogen could be substantial if left unchecked. To our knowledge, this is the first report of C. pulchella as a pathogen of sweet cherry trees in Spain. References: (1) M. E. Barr. Mycologia 77:549, 1985. (2) U. Damm et al. Persoonia 20:39, 2008. (3) F. P. Trouillas et al. Plant Dis. 96:648, 2012.

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