scholarly journals Apricot latent virus – Review

2012 ◽  
Vol 39 (No. 3) ◽  
pp. 144-148 ◽  
Author(s):  
L. Grimová ◽  
P. Ryšánek

Apricot latent virus (ApLV) is a definitive species of the Foveavirus genus, the Betaflexiviridae family. Although the virus is not highly prevalent, it was identified in several European and Mediterranean countries thus far. Biological experiments demonstrated that, in addition to the only known natural host, Prunus armeniaca, ApLV can be experimentally graft-transmitted to several Prunus species. Therefore, the eradication of the viral pathogen largely depends on the use of virus-free propagating materials and rootstocks, which should be seriously considered when designing and implementing stone fruit certification schemes. Although ApLV is not present on the list of viruses and other pathogens that require testing in the EPPO certification schemes for the production of healthy stone fruit trees for planting, Peach asteroid spot disease (PAS) causing agent whose occurrence was often justly correlated with ApLV, is included on the list. This review summarises the current available knowledge of ApLV on the biological, morphological, physicochemical and molecular levels and includes the contemporary management approaches.

Plant Disease ◽  
2020 ◽  
Author(s):  
Rachid Tahzima ◽  
Radouane Qessaoui ◽  
Yoika Foucart ◽  
Sebastian Massart ◽  
Kris De Jonghe

Plum (Prunus domestica L., Rosaceae) trees, like many stone fruit trees, are known to be infected by numerous plant viruses, predominantly as consequence of their clonal mode of propagation and perennial cultivation (Jelkmann and Eastwell, 2011). Apricot vein clearing-associated virus (AVCaV) is a member of the genus Prunevirus in the family Betaflexiviridae. AVCaV was first reported in Italy infecting apricot (P. armeniaca L.) associated with foliar vein clearing symptoms (Elbeaino et al. 2014). It has also been detected in various Prunus species, like plum, Japanese plum (P. salicina L.), sour cherry (P. cerasus L.), and Japanese apricot (P. mume L.), apricot and peach (P. persica L.) sourced from Asian and European countries (Marais et al. 2015), as well as in the ornamental Myrobolan plum (P. cerasifera L.) in Australia (Kinoti et al. 2017). In 2018, during the vegetative season, a survey was carried out in two different apricot and plum orchards in the southern region of Agdez (Agadir, Morocco) where stone fruit trees are grown. Five branches with leaves were sampled from three apricot and three plum trees of unknown cultivars, all asymptomatic. Total RNA was extracted from 100 mg plant tissue (leaves and cambial scrapping) using RNeasy Plant Mini Kit (QIAGEN, Hilden, Germany) and separate samples (one per species) were used for library preparation (NEBNext Ultra RNA library kit; New England BioLabs, MA, USA), and sequencing (Illumina NextSeq v2, totRNA sequencing) at Admera Health (New Jersey, USA). All generated reads (6,756,881) from the plum sample were quality filtered and submitted to the VirusDetect pipeline (Zheng et al., 2017). The plum cDNA library, a total of 20 viral contigs (68-1928 bp) mapped to several AVCaV accessions in GenBank. A reference mapping (CLC Genomics Workbench 12, Qiagen, Denmark) was conducted against all four available AVCaV full genomes (KM507062-63, KY132099 and HG008921), revealing 100% coverage of the full sequence (8358 nt) with 97-98 % nucleotide (nt) identities (BLASTn). Analysis of the derived sequences allowed to identify the location of the four predicted ORFs i.e. (ORF1: 6066 nt/2,021 aa), (ORF2: 1383 nt/460 aa), (ORF3: 666 nt/221 aa) and (ORF4: 420 nt/139 aa), previously described for the AVCaV genome (Elbeaino et al. 2014). The amino acid sequences of the encoded proteins of AVCaV isolate from Morocco also shared 97-98% identities with the corresponding sequences of complete genome AVCaV isolates in GenBank. To confirm the detection of AVCaV in the three plum samples, specific RT-PCR primers (VC37657s: 5’-CCATAGCCACCCTTTTTCAA-3’ / VC28239a: 5’-GTCGTCAAGGGTCCAGTGAT-3’) (Elbeaino et al. 2014) were used and the expected 330 bp fragment from the replicase gene was amplified in all three samples and subsequently sequenced (MT980794-96). Sanger sequences were 100% identical to corresponding HTS derived sequence. This is the first report of AVCaV infecting plum in Africa. The incidence of AVCaV in Moroccan Prunus species is unknown. Plum trees from the surveyed orchards were also confirmed to be co-infected with little cherry virus 1 (LChV-1) using HTS. Further investigation is required to determine the impact of AVCaV on these asymptomatic plum trees and other stone fruits species.


Plant Disease ◽  
2018 ◽  
Vol 102 (7) ◽  
pp. 1402-1409 ◽  
Author(s):  
Providence Moyo ◽  
Ulrike Damm ◽  
Lizel Mostert ◽  
Francois Halleen

Stone fruit trees (Prunus spp.) are economically important fruit trees cultivated in South Africa. These trees are often grown in close proximity to vineyards and are to a large extent affected by the same trunk disease pathogens as grapevines. The aim of the present study was to determine whether stone fruit trees are inhabited by Diatrypaceae species known from grapevines and whether these trees could act as alternative hosts for these fungal species. Isolations were carried out from symptomatic wood of Prunus species (almond, apricot, cherry, nectarine, peach, and plum) in stone fruit growing areas in South Africa. Identification of isolates was based on phylogenetic analyses of the internal transcribed spacer region and β-tubulin gene. Forty-six Diatrypaceae isolates were obtained from a total of 380 wood samples, from which five species were identified. All five species have also been associated with dieback of grapevine. The highest number of isolates was found on apricot followed by plum. No Diatrypaceae species were isolated from peach and nectarine. Eutypa lata was the dominant species isolated (26 isolates), followed by Cryptovalsa ampelina (7), Eutypa cremea (5), Eutypella citricola (5), and Eutypella microtheca (3). First reports from Prunus spp. are E. cremea, E. citricola, and E. microtheca. Pathogenicity tests conducted on apricot and plum revealed that all these species are pathogenic to these hosts, causing red-brown necrotic lesions like those typical of Eutypa dieback on apricot.


2013 ◽  
Vol 49 (No. 2) ◽  
pp. 65-69 ◽  
Author(s):  
J. Salava ◽  
J. Polák ◽  
I. Oukropec

Sharka disease caused by the infection with the Plum pox virus (PPV) in stone fruit trees is worldwide the most devastating for stone fruit production. Until now, good sources of resistance to PPV within the peach group have not been available. There are no commercial cultivars of peach that are resistant to PPV. Other Prunus species are known to show varying levels of resistance. Interspecific hybrids GF 677 (Prunus amygdalus × P. persica) and Cadaman (P. davidiana × P. persica) were revealed to be resistant to PPV. The resistance to a Dideron isolate of the descendants of Cresthaven × GF 677 and Cresthaven × Cadaman and their progenitors was evaluated after inoculation by chip-budding in a sealed screenhouse. Results demonstrate a certain level of resistance in both progenies of interspecific hybrids and indicate a potential for PPV resistance transfer to commercial peach cultivars but it will be necessary to perform backcrosses with peach cultivars of agricultural interest in order to return pomological and agronomic traits. For the definitive confirmation of resistance/susceptibility it will be necessary to wait until the adult stage of hybrids.


2000 ◽  
Vol 10 (4) ◽  
pp. 744-751 ◽  
Author(s):  
Stephen M. Southwick ◽  
Kitren Glozer

Many commercially grown stone fruit including apricots (Prunus armeniaca L.), peaches and nectarines [P. persica (L.) Batsch], plums (P. salicina Lindl., P. domestica L.), prunes (P. domestica L.), and pluots (P. salicina × P. armeniaca) have a tendency to produce high numbers of flowers. These flowers often set and produce more fruit than trees can adequately size to meet market standards. When excessive fruit set occurs, removal of fruit by hand thinning is necessary in most Prunus L. species to ensure that remaining fruit attain marketable size and reduce biennial bearing. Over the years there have been numerous attempts to find chemical or physical techniques that would help to reduce the costs associated with and improve efficiencies of hand thinning, however, alternate strategies to hand thinning have not been widely adopted for stone fruit production. In the past 10 years, several chemical treatments have shown promise for reducing hand thinning needs in stone fruit. Management of flowering by chemically reducing the number of flowers has been particularly promising on stone fruit in the Sacramento and San Joaquin Valleys of California. Gibberellins (GAs) applied during May through July, have reduced flowering in the following season in many stone fruit cultivars without affecting percentage of flowers producing fruit. As a result, fruit numbers are reduced, the need for hand thinning is reduced and in some cases eliminated, and better quality fruit are produced. There are risks associated with reducing flower number before climatic conditions during bloom or final fruit set are known. However, given the changes in labor costs and market demands, the benefits may outweigh the risks. This paper reviews relevant literature on thinning of stone fruit by gibberellins, and summarizes research reports of fruit thinning with GAs conducted between 1987 and the present in California. The term thin or chemically thin with regard to the action of GA on floral buds is used in this paper, consistent with the literature, although the authors recognize that the action of GA is primarily to inhibit the initiation of floral apices, rather than reduce the number of preformed flowers. At relatively high concentrations, GA may also kill floral buds. Chemical names used: gibberellic acid, potassium gibberellate.


Plant Disease ◽  
2021 ◽  
Author(s):  
Jun Zhou ◽  
Fei Xing ◽  
hongqing wang ◽  
shifang li

Plum pox or Sharka disease, caused by infection with plum pox virus (PPV), results in enormous economic losses to the stone fruit industry. However, the frequency and distribution of PPV remains unclear in China, the world’s largest stone fruit producer. Systemic visual surveys were performed on stone fruit trees in China from 2008 to 2018, and the results suggest that plum pox disease is widely distributed on common apricots (Prunus armeniaca) and Japanese apricots (P. mume), with an average symptoms incidence rate >30% in the latter. In samples collected from Beijing, Nanjing, Shanghai, Wuhan, Wuxi, and Yuncheng, PPV was detected in 77% (85 out of 110) of collected samples by immunochromatographic (IC) strip tests and RT-PCR, and 96% (67 out of 70) of samples showing Sharka symptoms were PPV-positive. Transmission electron microscopy revealed filamentous particles of ~640 × 12.5 nm (n = 19) in size, and pinwheel inclusions in symptomatic plants, but not in the asymptomatic and PPV negative plant. Full-length genomes were determined for four isolates (three from Japanese apricot and one from common apricot), and phylogenetic analyses indicated that all four isolates belong to a clade PPV-D, despite slight differences in genome size. These findings not only highlight the widespread occurrence and distribution of PPV in China, but also provide detailed information about the genomic characteristics and evolutionary position of PPV isolates in China.


2014 ◽  
pp. 30-34
Author(s):  
András Bozsik

The European stone fruit yellows (ESFY) is an important endemic disease in Europe which causes in both, the Mediterranean countries and Central Europe serious damage. Its pathogen is the ‘Candidatus Phytoplasma prunorum’. The treatment and healing of the diseased trees and plantations with chemicals do not promise success. Thus, prevention may be the only solution. The transmission and spread of the pathogen happen by infected propagation material (grafting) or a vector (the psyllid, Cacopsylla pruni). Mechanism of the pathogen’s transmission and population dynamics of the vector have been extensively investigated in several European countries, which may allow by the control of C. pruni even to hold back the disease. Diseased stone fruit trees and wild Prunus spp. as main host species play an important role in maintaining and spreading the pathogen. C. pruni collects the pathogen by feeding on these plants and it carries persistently ‘Ca. P prunorum’. Researchers in Hungary have been characterized the disease only in terms of plant pathology, but neither the significance of the vector nor the role of wild Prunus spp. have been studied. This summary intends to give clues to these researches, that not only axe and saw should be the instruments of national control, but knowing the role and population dynamics of the vector the stone fruit production should be more successful.


Hilgardia ◽  
1933 ◽  
Vol 8 (3) ◽  
pp. 83-123 ◽  
Author(s):  
Edward E. Wilson

2021 ◽  
Vol 7 (3) ◽  
pp. 171
Author(s):  
Reannon L. Smith ◽  
Tom W. May ◽  
Jatinder Kaur ◽  
Tim I. Sawbridge ◽  
Ross C. Mann ◽  
...  

The Podosphaera tridactyla species complex is highly variable morphologically and causes powdery mildew on a wide range of Prunus species, including stone fruit. A taxonomic revision of the Po. tridactyla species complex in 2020 identified 12 species, seven of which were newly characterised. In order to clarify which species of this complex are present in Australia, next generation sequencing was used to isolate the fungal ITS+28S and host matK chloroplast gene regions from 56 powdery mildew specimens of stone fruit and ornamental Prunus species accessioned as Po. tridactyla or Oidium sp. in Australian reference collections. The specimens were collected in Australia, Switzerland, Italy and Korea and were collected from 1953 to 2018. Host species were confirmed using matK phylogenetic analysis, which identified that four had been misidentified as Prunus but were actually Malusprunifolia. Podosphaera species were identified using ITS+28S phylogenetic analysis, recognising three Podosphaera species on stone fruit and related ornamental Prunus hosts in Australia. These were Po.pannosa, the rose powdery mildew, and two species in the Po. tridactyla species complex: Po. ampla, which was the predominant species, and a previously unidentified species from peach, which we describe here as Po. cunningtonii.


Author(s):  
V. P. Hayova

Abstract A description is provided for Leucostoma cinctum. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. DISEASE: Leucostoma cinctum, especially in its conidial state, is a well-known pathogen of stone-fruit trees causing necrosis of twigs, perennial Cytospora-canker. The fungus penetrates mainly through the scars, and may result in dieback of branches or even whole trees. Tree susceptibility to L. cinctum is influenced by lesions (Stanova, 1990). Comparative anatomy and host response of peach cultivars inoculated with L. cinctum was studied by Biggs (1986). Resistance of different cultivars of stone-fruit trees to L cinctum has been investigated by many authors (Cociu et al., 1991; Miles et al., 1989; Pedryc & Rozsnyai, 1991). HOSTS: On dead or dying, attached or fallen twigs of the Rosaceae, mainly Prunoideae (Amygdalus, Armeniaca, Cerasus, Persica, Prunus) and rarely other subfamilies of the Rosaceae, including genera such as Cotoneaster, Crataegus, Malus and Pyrus. GEOGRAPHICAL DISTRIBUTION: Asia: Armenia, Republic of Georgia, Iran, Kazakhstan, Russia, Turkmenistan, Uzbekistan. Australasia: Australia. Europe: Czech Republic, France, Germany, Hungary, Italy, Moldova, Rumania, Russia, Slovakia, Spain, Switzerland, Sweden, Turkey, UK, Ukraine, former Yugoslavia. North America: Canada, USA (Idaho, Michigan, New-Jersey, Oregon). TRANSMISSION: Both conidia and ascospores are air-borne, especially under humid conditions. Orange or reddish droplets or tendrils of conidia extruded from conidiomata can be often seen after rain. It is also known that arthropods can carry propagules in stone-fruit orchards (Helton et al., 1988).


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