PM 7/064 (2) <i>Xanthomonas arboricola</i> pv. <i>pruni</i>

EPPO BulletinVolume 51, Issue 2 p. 240-266 DIAGNOSTICSFree Access PM 7/064 (2) Xanthomonas arboricola pv. pruni First published: 16 August 2021 https://doi.org/10.1111/epp.12756 1Use of brand names chemicals or equipment in these Standards implies no approval them to the exclusion others that may also be suitable. AboutSectionsPDF ToolsRequest permissionExport citationAdd favoritesTrack citation ShareShare Give accessShare full text full-text accessPlease review our Terms and Conditions Use check box below share version article.I have read accept Wiley Online Library UseShareable LinkUse link a this article with your friends colleagues. Learn more.Copy URL Share linkShare onFacebookTwitterLinked InRedditWechat Abstract Specific scope This Standard describes diagnostic protocol for pruni.1 should used conjunction 7/76 protocols. amendment Approved 2005–09. Revised 2021–03. 1 INTRODUCTION Bacterial spot stone fruits is disease caused by was described first time USA (Michigan) 1903 on Prunus salicina (Japanese plum) (EPPO/CABI, 1997). The main hosts economic importance are P. persica (peach), var. nucipersica (nectarine), domestica (plum), armeniaca (apricot) dulcis (almond) (Young, 1977; Stefani et al., 1989; Scortichini & Simeone, 1997; Palacio-Bielsa 2010). Species Sino-Japanese group (P. salicina) generally more susceptible than European plums (Bazzi Mazzucchi, 1980, 1984; Topp Bazzi 1990a,b; 1990). Other avium cerasus (sweet sour cherries), mume apricot), davidiana (Chinese wild peach), buergeriana, crassipes donarium. Ornamental species such as laurocerasus (cherry laurel) affected (Marchi 2011; Tjou 2012). In absence conditions conducive infection, bacteria capacity survive extended periods protected sites trees. During cold dormancy, persist buds, axils twig lesions (Zaccardelli 1995; Battilani 1999). X. an epiphyte orchards nurseries, associated buds leaf scars. From these, it can enter host before healing scar, through stomata. Further details geographic distribution found Global Database (EPPO, 2020). information biology available data sheet different methodologies diagnosis bacterial symptomatic asymptomatic plants species. A flow diagram describing procedure presented Figure 1. FIGURE 1Open figure viewerPowerPoint Flow-diagram testing plant samples IDENTITY Preferred name: (Smith, 1903) Vauterin, Hoste, Kersters Swing 1995. scientific names: Pseudomonas (Smith), campestris Dye, (Smith) Dowson. Taxonomic position: Bacteria, Gammaproteobacteria, Lysobacterales, Lysobacteraceae. Code: XANTPR. Phytosanitary categorization: A2 list no. 62, EU RNQP (Annex IV), PZ Quarantine pest III). 3 DETECTION 3.1 Disease symptoms Symptoms observed leaves, young fully developed fruits, twigs, branches trunks 2003, 2006). orchards, although trees develop parts, they appear healthy if not inspected closely. However, nursery plantlets, heavy infections detected easily, mainly (peach nectarine), because defoliation chlorosis leaves (Figure 2). Some cultivars belonging very sensitive severe cankers die within few years 1980). become obvious during warm seasons temperatures 19–28°C, frequent rain, wind dew, which all favourable infection (Fahy Persley, 1983; Bradbury, 1986; Du Plessis, 1988; Zehr Shepard, 1996). 2Open Plantlets infected showing defoliation. Courtesy Plant Health Service, Valencian Government (ES) 3.1.1 On domestica, salicina, dulcis, armeniaca, (cherry), apparent lower surface small, water-soaked 3) into pale-green later yellow circular irregular areas (spots lesions) light-tan centre. These spots soon evident upper enlarge turn angular dark deep-purple, brown black. immediate surrounding tissue (Figures 4 5). show typical three-band colour (green-yellow-brown) 6), followed 3Open stage persica. Service. 4Open Typical peach cv. ‘Zee Lady’ pruni. Emilio Stefani, UNIMORE (IT) 5Open (a, b) Angular chlorotic tissue. (a) apricot (b) almond Miguel Cambra Álvarez, CPV-Government Aragón 6Open Both old exhibit tatter symptoms, but believed most initiated leaves. circular, irregularly shaped, reddish colour. As dry out drop shot-holes 7), often surrounded ring, formed leaf. Spots usually concentrated towards tip, sheltered parts blades along midrib multiply region droplets rain dew. ooze spots. 7Open Tatter tree suspected co-infected fungal pathogens. (Japanese-plum) initial spots, rapidly turning reddish-brown, then dark-brown necrotic, whereas minimal less 8). necrotic frequently perforate, so shot-hole effect pronounced. Affected plum do fall. 8Open Necrotic Japanese ‘Fortune’. ornamental laurel), chlorotic, having centre distinct round margin, readily abscise, resulting appearance 9). 9Open cherry laurel (upper surface) Maria Bergsma-Vlami, NVWA (NL) Possible confusion easily confused those other pathogens, ‘shot-hole’ Wilsonomyces carpophilus Venturia carpophila, even stages Polystigma fulvum Tranzschelia pruni-spinosae; however, evolve differently. Apple virus (ACLSV) ring (PNRSV) Confusion possible diseases syringae morsprunorum syringae, fall prematurely Pseudomonads. It noted produces foliar prunicola (López 2018) cause persica, similar pruni, well gummosis (3.1.3). Finally, some abiotic factors lead copper phytotoxicity, larger (2–6 mm diameter) shape 10a) unlike 10b). Frequently, halo, around 10Open confusion. Copper phytotoxicity nectarine ‘Diamond Ray’. 3.1.2 3–5 weeks after petal until skin changes, when ripening process begins physiochemical parameters change. occur hail damage. carpophila. nectarine) small surface. Lesions sunken, margins light-green halos give mottled fruit. result natural enlargement fruit, pitting cracking vicinity 11 12). cracks difficult see, occurs wide visible fruit 13-15). Gum flow, particularly from wounds 16); insect 11Open Pitting 12Open 13Open Severe peaches, 14Open nectarines, ‘Big Haven’. 15Open Very immature apricots, ‘Lady Cot’. 16Open quite different; large, sunken black 17) common cultivars, while, only pit-like occur. depends cultivar susceptibility. (European common: lesions, necrotizing 18). 17Open Large ‘Golden plum’ area. Remedios Santiago Merino, LSV-Junta de Extremadura 18Open plum, ‘Čačanska Rana’. 19Open Sunken, corky oozing gum streams clumps 20Open Raised 21Open Circular endocarp 22Open Almond mummies early results distorted epidermis stone. specific fruits. Infected initially display 19). Later, mesocarp dehydrates, raised 20). cases, endocarp, affect nut 21). either mummify remain harvest 22). contain viable bacteria, therefore serving inoculum source thereafter. 3.1.3 twigs Twig (black tip) commonly fruit/nut symptoms. spring top portion overwintering water sprouts green shoots produced; water-soaked, slightly darkened, superficial blisters extend 1–10 cm parallel long axis girdle it. case, tip die, while immediately area, present, characteristically (‘black tip’ injury) 23). season summer dark-purplish lenticels. limited, dark, elliptical margin. When affecting Fusicoccum amygdali (synonym Phomopsis amygdali) infections. 23Open Tip branches, perennial, contrast peach, continue developing old. inner bark penetrated, deep-seated deform kill 24 25). Cankers pathogens Leucostoma cincta Eutypa lata extremely rare. 24Open Young canker ‘Anne Gold’ 25Open 2–3-year-old Plum’ current season's wood elongated length twig, depressed shiny, greasy margin 26). If lesion expands dieback will branches. 26Open ‘Marta’ Detail. Montserrat Roselló Pérez, LDF-Valencian been observed. For detailed see Dunegan (1932), Anderson (1956), Hayward Waterston (1965), McIver (1973), Moffett Gasperini al. (1984), Plessis (1988), Goodman Hattingh Shepard (1994), Ritchie (1995) (2012). 3.2 Detection material Isolation two molecular tests (one test where established) conventional PCR (Appendix 3), real-time 4) LAMP 5) recommended detection material. critical 3.2.1 species, isolated (water-soaked) cankers. Generally, isolation challenging and, continues, pathogen becomes difficult. remains easy ripen. pieces (1–2 mm) taken has sterilized 70% ethanol. crushed mortar comminuted, adding drops sterile phosphate-buffered saline (PBS). After crushing, mL PBS (see Appendix 1) added suspension left settle up 10 min (longer settling would oxidation sample, loss cell viability). case laurel, incubated approximately 30 at room temperature. dilution-plating method spread 20–50 µL aliquots 10-fold 100-fold dilutions same buffer onto Wilbrink, YPGA (yeast-peptone-glucose agar), GYCA (glucose-yeast extract-calcium carbonate agar) YDC (yeast extract-dextrose-calcium 1). plates 28°C 2–3 days. colonies domed, smooth, mucoid glistening: bright, creamy yellow, tendency darken little, yellow-orange age depending media 27 28). 27Open Pure culture grown 4–5 days 23°C. LSV – Junta Alvarez, 28Open pure GYCA. Another semi-selective medium mXCP1 (Xanthomonas axonopodis phaseoli medium) incubation days, mucoid, hydrolysis Tween 80 soluble potato starch light halo 29). re-streaked Nutrient Agar (NA), YPGA, obtain cultures further identification. 29Open 5 incubation. Daniel Bakker/Harrie Koenraadt, Naktuinbouw (Pantoea spp. spp.), living association crops, produce above-described media, their colony might brilliance intensity Phytopathogenic isolates complex, causing grow above media; fail bright colonies. Therefore, production pigment help selection presumptive Confirmation identity needs performed. King's B medium, several phytopathogenic pseudomonads fluorescent pigment, does round-flat morphology 30). saprophytes growing fluorescence either. 31). 30Open 25°C. 31Open (on right) left) medium. Ester Marco-Noales, IVIA 3.2.2 Rapid screening facilitate plants. Conventional (Pothier 2011a), (Palacio-Bielsa 2011) (Bühlmann 2013) Appendices 3–5. laboratories experience problems Bühlmann (2013) particular inclusivity exclusivity. Cross-reactions At least based DNA sequence targets genome need included screening. established, one sufficient. 3.3 Two 3.3.1 Test sample requirements Samples consist 100 dormant budchips, late winter (1 year old). One budchip each cut budchips collected Stomacher bag. single large (used scions grafting) tested, them. 3.3.2 Extraction prepared according section put bag (10 mM), temperature under agitation (100 rpm). non-concentrated extract, directly remaining extract tested increase probability compared sample. centrifugation 20 000g. supernatant discarded pellet resuspended 1.5 Phosphate mM, pH 7.2) testing. part both kept –20°C addition 15%–20% glycerol. Alternatively, 0.05 M K-phosphate buffer, 7.0 filtered gauze 50 centrifuge tube spin 480 g. poured new centrifuged again 12 000 g min. 1–2 final concentrate. concentrate (0.5–1 mL) 15–20% 3.3.3 Direct dilution-plate resembling selected purified. 3.3.4 Molecular performed using targets. 2013 IDENTIFICATION identified biological principles (e.g. combinations serological tests) genome. Known reference strains test. 4.1 Serological methods Depending availability validated antibodies, suspensions (containing 106 cfu/mL) immunofluorescence protocols 7/97 (1) Indirect pathogenic 2009). Recommended polyclonal antisera PRI-I-731-BCD-08 X10-713-BCD-08. Netherlands identification IF 6). 4.2 4.2.1 Appropriate procedures 2011a,b) used, following 7. 4.2.2 Real-time (2011) 4. Garita-Cambronero (2017) 8. routine (Xap), use conjuction amplification xopE3 gene (Garita-Cambronero 2017). positive, isolate could Xap hand, bacterium shows positive designated member Xap-look-a-like group. 4.2.3 5. 4.2.4 fingerprinting comparison genomic between type means rep-PCR useful [see 7/100 Rep-PCR 2010, 2014)]. 4.3 provide additional support 4.3.1 barcoding Procedures 7/129 tool pests. Single locus typing partial gyrB closely related (Parkinson 4.3.2 Biochemical Gram-negative bacterium, rod-shaped, motile flagellum, measuring 0.2–0.4 × 0.8–1.0 μm. strict aerobe optimum growth range 24–29°C. Different biochemical characteristics Fahy Persley (1983) Schaad (2001). 4.3.3 Hypersensitivity pathogenicity hypersensitivity reaction (HR) tobacco cvs ‘Samsun’ ‘Xanthi’) tomato ‘Moneymaker’ ‘Roma’) 48 h concentration about 109 cfu/mL distilled (Klement, 1963; Klement 1964). HR 24–48 h, atypical turgidity infiltrated area 48–72 h. Five inoculation, collapse 32). 32Open Atypical ‘Xanthi’ inoculation: