scholarly journals Natural Outbreak of a Bacterial Fruit Rot of Cantaloupe in Georgia Caused by Acidovorax avenae subsp. citrulli

Plant Disease ◽  
2000 ◽  
Vol 84 (3) ◽  
pp. 372-372 ◽  
Author(s):  
R. R. Walcott ◽  
D. B. Langston ◽  
F. H. Sanders ◽  
R. D. Gitaitis ◽  
J. T. Flanders
Keyword(s):  
Tween 80 ◽  
Soft Rot ◽  
Fatty Acid Analysis ◽  
Fruit Rot ◽  
Enzyme Linked Immunosorbent Assay ◽  
Identification System ◽  
Microbial Identification ◽  
Leaf Tissues ◽  
Different Sources ◽  
Natural Outbreak

In April and July 1999, cantaloupe plants (Cucumis melo) from commercial greenhouses and fields in Grady, Colquitt, Mitchell, and Tift counties, GA, exhibited severe foliar necrosis and a fruit rot. Foliar symptoms were V-shaped, necrotic lesions occurring at the margin of the leaf and extending inward toward the midrib. Symptoms on the fruit surface were observed after net development and occurred randomly as round, necrotic, sunken spots or cracks a few millimeters in diameter. A soft rot originating from lesions on the surface of the fruit expanded into the flesh. Approximately 5% of the fruits were affected. Bacteria recovered from cantaloupe fruit and leaf tissues produced nonfluorescent, smooth, off-white colonies on King's medium B. Characteristic of Acidovorax avenae subsp. citrulli, the bacteria produced pits in carboxymethyl cellulose media (WFB 44), and reduced Tween 80 to give a visible precipitate on WFB 68 media (1). Based on fatty acid analysis, all strains were identified as A. avenae subsp. citrulli by Microbial Identification System software, version 3.6 (MIDI, Newark, DE), and similarity indices of 0.06, 0.79, 0.21, and 0.43 were recorded for strains recovered form Grady, Tift, Colquitt, and Mitchell counties, respectively. Using specific oligonucleotide primers (WFB 1/2) (2), PCR conducted on DNA from each strain yielded a 390-bp DNA fragment, confirming similarity to A. avenae subsp. citrulli. Indirect enzyme-linked immunosorbent assay with genus-specific antibodies also verified that the bacteria were Acidovorax spp. Pathogenicity of the A. avenae subsp. citrulli strains was confirmed by inoculating and observing symptom development on 2-week-old watermelon seedlings. Although all strains were identified and confirmed as A. avenae subsp. citrulli, restriction fragment length polymorphism data indicated that the Tift County strain was distinguishable from the others, suggesting that inoculum for these outbreaks may have originated from at least two different sources. References: (1) R. D. Gitaitis. 1993. Development of a seedborne assay for watermelon fruit botch. Pages 9–18 in: Proc. 1st Int. Seed Testing Assoc. Plant Dis. Commit., Ottawa, Canada. (2) R. R. Walcott and R. D. Gitaitis. (Abstr.) Phytopathology 88(suppl.):S92, 1998.

scholarly journals First Report of a Fruit Rot of Pumpkin Caused by Acidivorax avenae subsp. citrulli in Georgia

Plant Disease ◽  
1999 ◽  
Vol 83 (2) ◽  
pp. 199-199 ◽  
Author(s):  
D. B. Langston ◽  
R. D. Walcott ◽  
R. D. Gitaitis ◽  
F. H. Sanders
Keyword(s):  
Polyclonal Antibodies ◽  
Pcr Amplification ◽  
Tween 80 ◽  
Soft Rot ◽  
Fruit Rot ◽  
Identification System ◽  
Banding Patterns ◽  
First Report ◽  
Microbial Identification ◽  
Necrotic Spots

In September 1998, a fruit rot was reported affecting pumpkin (Cucurbita pepo) in a commercial field in Terrell Co., Georgia. Symptoms on the surface of fruit occurred as round, necrotic spots or cracks a few millimeters in diameter. With age, the tissue surrounding these lesions became soft and wrinkled. A soft rot expanded into the flesh of the pumpkin, originating from the lesions observed on the surface. In time, infected pumpkins totally collapsed. V-shaped, necrotic lesions occurred at the margin of the leaf and extended inward toward the mid-rib. Samples were collected from the field and bacteria were isolated from fruit and leaf lesions onto King's medium B (1). The bacterium isolated was rod shaped, gram negative, nonflourescent, oxidase positive, Tween 80 positive, carboxymethyl cellulose positive, β-OH butyrate positive, and malonate negative. The bacterium reacted positively with polyclonal antibodies specific for the watermelon fruit blotch pathogen Acidivorax avenae subsp. citrulli and was identified as A. avenae subsp. citrulli by MIDI (Microbial Identification System, Newark, DE) according to statistical analysis of fatty acid data. Results from polymerase chain reaction (PCR) amplification of the bacterium isolated from pumpkin yielded 360-bp fragments that, when digested with the restriction enzyme HaeIII, had DNA banding patterns identical to those of stock A. avenae subsp. citrulli DNA. Koch's postulates were completed successfully with 2-week-old watermelon seedlings. This is the first report of A. avenae subsp. citrulli causing fruit rot of pumpkin in Georgia. Reference: (1) E. O. King et al. J. Lab. Clin. Med. 44:301, 1954.

scholarly journals Fruit Rot of Tinda Caused by Pseudomonas aeruginosa–A New Report from India

Plant Disease ◽  
2012 ◽  
Vol 96 (1) ◽  
pp. 141-141 ◽  
Author(s):  
K. K. Mondal ◽  
C. Mani ◽  
J. Singh ◽  
S. R. Dave ◽  
D. R. Tipre ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
16S Rrna ◽  
Bacterial Species ◽  
Soft Rot ◽  
Fruit Rot ◽  
Polar Flagellum ◽  
Identification System ◽  
Rrna Gene ◽  
Causal Bacterium ◽  
Praecitrullus Fistulosus

Fruit rot disease (FRD), an emerging problem of tinda (Praecitrullus fistulosus) in India. FRD epidemics begin during rainy and warm weather and often spoil marketable produce. Symptoms appear as numerous, pale brown-to-dark brown, deeply penetrating circular soft rot lesions on fleshy fruit tissues. Noneffervescent bacterial exudates occasionally form on lesions. Repeated isolations from FRD-affected tinda fruits consistently yielded the same bacterial species. Inoculation of the isolated bacterium into asymptomatic tinda fruits produced identical soft rot symptoms. Fruits were inoculated with the isolate ITCC B0030 (0.1 OD) by removing a 2.0-cm deep tissue plug with a sterile cork borer (5 mm in diameter) and injecting the inoculum with a syringe in the cylindrical cavity. After inoculation, the plug (upper 5 mm) was reinserted, sealed with sterile paraffin, and covered with a small piece of wet absorbent cotton to prevent dehydration. High humidity (>90%) and 30 to 33°C temperature was maintained after inoculation in a glasshouse. After 4 to 10 days, fruits showed FRD symptoms. The reisolated bacterium from artificially inoculated symptomatic fruits was identical with the original inoculated bacterium. Identity of the bacterial pathogen for FRD was confirmed by phenotypic and genotypic methods. The causal bacterium was a gram-negative, non-sporing motile rod with a single polar flagellum. The bacterium produced yellowish green and blue-green diffusible pigments on King's B (KB) medium. On yeast dextrose calcium carbonate agar at 30°C, the colonies produced abundant, blue, diffusible pigment within 48 h. The bacterium grew at temperatures up to 42°C but not at 4°C. Excellent growth occurred on Salmonella-Shigella agar and MaConkey's medium, as reported also for Pseudomonas aeruginosa strain P8. The bacterium produced ammonia, hydrogen sulfide, arginine dihydrolase, urease, lipase, catalase, gelatinase, and casinase but not amylase, indole, or acetyl methyl carbinol. The bacterium was identified as P. aeruginosa using Biolog based Bacterial Identification System version 4.2 (Biolog Inc., Hayward, CA). The bacterium did not utilize cellobiose, dulcitol, maltose, sorbitol, sucrose, arabinose, and starch. Upon infiltration on tobacco leaves (Nicotiana tabacum cv. Xanthi) at 107 or more cells ml–1, the bacterium gave a strong hypersensitive reaction within 24 h. Transmission electron micrographs (TEM, KYKY 1000B, Japan) of the causal bacterium revealed a single, polar flagellum. Identity was further confirmed as P. aeruginosa based on 16S rRNA sequence (1,491 nt) analysis with universal primers F1 (5′-GAGTTTGATCCTGGCTCAG-3′) and R13 (5′-AGAAAGGAGGTGATCCAGCC-3′). A blastN search of GenBank revealed a >99% nt identity with P. aeruginosa strain TAUC 7 (HQ914782). The 16S rRNA gene sequence (1,491 nt) was deposited in Bankit GenBank (JF797204). To our knowledge, this is the first report of fruit rot of tinda caused by P. aeruginosa in India (ITCC B0030) and a new record of bacterial rot of Praecitrullus fistulosus induced by a fluorescent and blue-green pigment producing P. aeruginosa. To date, P. syringae pv. lachrymans and a nonfluorescent P. pseudoalcaligenes subsp. citrulli were reported to infect Citrullus lanata (1) and Praecitrullus fistulosus (2), respectively. References: (1) D. L. Hopkins and N. C. Schenck. Phytopathology 62:542, 1972. (2) N. W. Schaad et al. Int. J. Syst. Bacteriol. 28:117, 1978.

scholarly journals First Report of Soft Rot Caused by Pectobacterium carotovorum on Pinellia ternata in China

Plant Disease ◽  
2007 ◽  
Vol 91 (10) ◽  
pp. 1359-1359 ◽  
Author(s):  
F. X. Ying ◽  
X. F. Hu ◽  
J. S. Chen
Keyword(s):  
Disease Outbreaks ◽  
Soft Rot ◽  
Shanxi Province ◽  
Identification System ◽  
Pectobacterium Carotovorum ◽  
Gene Encoding ◽  
Pinellia Ternata ◽  
First Report ◽  
Microbial Identification ◽  
Physiological And Biochemical Characteristics

Pinellia ternata (Thumb.) Breit. (Araceae) is a traditional herb used as an antivomit, anticough, analgesic, and sedative in China for more than 1,000 years. From the summer through fall of 2003 to 2005, a high incidence (approximately 10 to 25%) of disease outbreaks characterized by water-soaked lesions and soft rot with a stinky odor were observed in the cultivated P. ternata in Shanxi Province. Water-soaked lesions were first observed on the stem base and then the plant collapsed, although the upper portion remained asymptomatic. Subsequently, the lesions expanded rapidly over the entire plant. The macerated tuber was usually reduced to a whitish, mushy, and foul-smelling pulp surrounded by undecayed periderm. A Pectobacterium species was consistently recovered from the diseased tubers on nutrient agar media. Koch's postulates were completed by stab inoculating 6-week-old peach- and willow-leaved P. ternata cultivars with the bacterial suspensions (1 × 108 CFU/ml) (1). Ten control plants for each cultivar were inoculated with sterile water. After inoculation, plants were maintained in a growth chamber at 25°C with relative humidity ranging from 80 to 90%. After 2 to 3 days, typical soft rot symptoms were observed on the inoculated plants. A Pectobacterium species was reisolated from the symptomatic tubers while control plants remained healthy. This experiment was repeated in May, July, and September. The pathogenic isolates were identified as typical Pectobacterium carotovorum on the basis of morphological, physiological, and biochemical characteristics (2). The Microlog system (version 3.5; Biolog, Hayward, CA) and Sherlock Microbial Identification System (version 4.5; MIDI Newark, DE) also identified them as Pectobacterium carotovorum on the basis of similarity indices more than 66.9 and 78.2%, respectively. Their identity was then confirmed by sequencing the gene encoding the 16S rRNA (GenBank Accession No DQ785511). To our knowledge, this is the first report of Pectobacterium carotovorum as the cause of soft rot of P. ternata. References: (1) H. R. Azad et al. Plant Dis.84:973, 2000. (2) L. Hauben et al. Syst. Appl. Microbiol. 21:384, 1998.

scholarly journals Wildfire of Soybean Caused by Pseudomonas syringae pv. tabaci, a New Disease in Korea

Plant Disease ◽  
2009 ◽  
Vol 93 (11) ◽  
pp. 1214-1214 ◽  
Author(s):  
I.-S. Myung ◽  
J.-W. Kim ◽  
S. H. An ◽  
J. H. Lee ◽  
S. K. Kim ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Pathogenic Bacteria ◽  
Similarity Index ◽  
Soft Rot ◽  
Universal Primers ◽  
Identification System ◽  
Bacterial Disease ◽  
Bacterial Strains ◽  
Microbial Identification ◽  
Soybean Leaves

In 2006 and 2007, a new bacterial disease was observed in field-cultivated soybeans in Boeun District and Munkyung City of Korea. The disease caused severe blighting of soybean (Glycine max) leaves. Soybean leaves in fields showed yellowish spots with brown centers. Brown and dead areas of variable size and shape were surrounded by wide, yellow haloes with distinct margins. Spots might coalesce and affected leaves fell readily. Seven bacterial strains were isolated from chlorotic areas of soybean leaves and all produced white colonies on trypticase soy agar. With the Biolog Microbial Identification System, version 4.2, (Biolog Inc., Hayward, CA) all strains and Pseudomonas syringae pv. tabaci CFBP2106T were identified as P. syringae pv. tabaci with a Biolog similarity index of 0.28 to 0.52 and 0.48 after 24 h. Pathogenicity of the strains (three plants per strain) on soybean leaves at the V5 stage (cv. Hwanggeum) was confirmed by rub inoculation with bacterial suspensions (1 × 108 CFU/ml) in sterile distilled water on the lesions cut 1 cm long on the upper side of the leaves with razor blades and by pinprick on 3-week-old leaves of tobacco (Nicotiana tabacum cv. Samsun) in the greenhouse. Wildfire symptoms on the soybean leaves and faint halos on tobacco leaves were observed 4 days after inoculation. The identification of reisolated bacterial strains was confirmed with the metabolic fingerprintings on Biolog. LOPAT tests (1) and phenotypic characteristics (3) of the strains were similar to those of the CFBP2106T. Colonies were levan positive, oxidase negative, potato soft rot negative, arginine dihydrase negative, and tobacco hypersensitivity negative. All strains were gram-negative, aerobic rods with a polar flagellum. Strains were negative for esculin hydrolysis, gelatin liquefaction, urea production, accumulation of poly-β-hydroxy butyrate, starch hydrolysis, ornithine dihydrolase, lysine dihydrolase, growth at 37°C, utilization of geraniol, benzoate, cellobiose, sorbitol, trehalose, l-rhamnose, and adonitol. Positive reactions were catalase and arbutin hydrolysis, utilization of sorbitol, d-arabinose, and dl-serine. The strains were variable in utilization of mannitol, sucrose, and d-arabinose. The 1,472-bp PCR fragments of strains, BC2366 (GenBank Accession No. FJ755788) and BC2367 (No. FJ755789) was sequenced using 16S rDNA universal primers (2). The sequences shared 100% identity with the analogous sequences of P. syringae pv. glycenea (GenBank Accession No. AB001443) available in NCBI databases. Based on the phenotypic, genetic, and pathological characteristics, all strains were identified as P. syringae pv. tabaci. To our knowledge, this is the first report of P. syringae pv. tabaci causing wildfire on soybean in Korea. References: (1) R. A. Lelliott et al. J. Appl. Bacteriol. 29:470, 1966. (2) I.-S. Myung et al. Plant Dis. 92:1472, 2008. (3) N. W. Schaad et al., eds. Laboratory Guide for Identification of Plant Pathogenic Bacteria. 3rd ed. The American Phytopathological Society, St. Paul, MN, 2001.

scholarly journals Recent Outbreaks of Black Rot of Brassicas Caused by Xanthomonas campestris pv. campestris in Southern Mozambique

Plant Disease ◽  
2009 ◽  
Vol 93 (11) ◽  
pp. 1218-1218
Author(s):  
J. Bila ◽  
A. M. Mondjana ◽  
E. G. Wulff ◽  
C. N. Mortensen
Keyword(s):  
Xanthomonas Campestris ◽  
Pathogenic Bacteria ◽  
Identification System ◽  
Black Rot ◽  
Microbial Identification ◽  
Brassica Spp ◽  
Brassica Crop ◽  
Leaf Tissues ◽  
Pathogenicity Tests ◽  
Xanthomonas Campestris Pv Campestris

In August and September of 2007, black rot symptoms were observed on seedbed and field plants of Brassica spp. grown in the southern districts of Boane, Mahotas, and Chòkwé in Mozambique. One hundred eighty-two cabbage-growing households were evaluated for the incidence of Xanthomonas campestris pv. campestris. Five Brassica cultivars, Glory F1, Glory of Enkhuizen, Copenhagen Market, Starke (Brassica oleracea pv. capitata L.), and Tronchuda (B. oleracea L. var. costata DC) were grown in the areas for several years. The hybrid Glory F1 was the most popular grown cultivar in the surveyed areas. In the Boane district, the highest incidence of black rot was recorded on Copenhagen Market (70%), Starke (67.9%), and Glory F1 (67.3%). In Chòkwé, Tronchuda (Portuguese kale) was the least affected Brassica crop. Water-soaked lesions starting at the edge of leaves with typical V-shaped necrotic lesions and vein discoloration were the most commonly observed symptoms. When examined with a microscope, cut edges of symptomatic stem and leaf tissues consistently exhibited bacterial streaming. The bacteria were isolated from commercial seed and field-grown plants on semiselective agar media (2). Forty-six X. campestris pv. campestris strains that were gram negative, aerobic, starch positive, nitrate negative, and oxidase negative or weakly positive (3) were further identified on the basis of ELISA (Agdia Inc., Elhart, IN), GN Biolog Microbial Identification System, version 4.2 (Biolog Inc., Hayward, CA), and PCR-specific primers (1). Pathogenicity tests were conducted by pin inoculating two upper leaves of cabbage (cv. Wirosa) in the 2- to 3-leaf stage with bacterial growth from 24-h-old agar cultures (2). Black rot symptoms developed on nearly all inoculated plants within 7 to 14 days. No symptoms were observed on control plants inoculated with a sterile pin without bacterial inoculum. The severity of black rot of Brassica spp. in three important farming districts caused significant losses in Mozambique. References: (1) T. Berg et al. Plant Pathol. 54:416, 2005. (2) S. J. Roberts and H. Koenraadt. Page 1 in: International Rules for Seed Testing: Annexe to Chapter 7 Seed Health Methods. ISTA, 2007. (3) N. W. Schaad et al. Laboratory Guide for Identification of Plant Pathogenic Bacteria. 3rd ed. The American Phytopathological Society, St. Paul, MN, 2001.

scholarly journals Application of the Biolog® Identification System for Aflatoxin-Producing Fungi Associated with Maize (Zea mays L.) Contamination in Romania

2020 ◽  
Vol 77 (2) ◽  
pp. 42
Author(s):  
Irina SMEU ◽  
Elena Mirela CUCU ◽  
Alina Alexandra DOBRE ◽  
Hellene CASIAN
Keyword(s):  
Zea Mays L ◽  
Rhizopus Oryzae ◽  
Health Concern ◽  
Enzyme Linked Immunosorbent Assay ◽  
Identification System ◽  
The European Union ◽  
Total Aflatoxin ◽  
Microbial Identification ◽  
European Regulations ◽  
Low Levels

Cereals are very susceptible to fungal attacks. Fungi have a unique biochemical pathway to assimilate a vast array of available substrates and produce toxic secondary metabolites, such as mycotoxins, which represent a clear public health concern. In this context, a maize survey was conducted in order to assess the diversity of mycotoxin-producing fungi. Low levels of total aflatoxins, acceptable by the European Union, were detected in maize samples. A semi-automated Biolog® Microbial Identification System was used for the identification of the fungal strains. Enzyme-linked immunosorbent assay (ELISA) was used for the quantification of total aflatoxins. The results indicated that Fusarium udum and Rhizopus oryzae were the prevalent fungi for the assessed maize samples, while both control and treated samples showed low levels of total aflatoxins, which did not exceed 1.5 μg kg-1. The registered total aflatoxin concentrations were consistent with the European regulations.

scholarly journals Bacterial Stem Rot of Oncidium Orchid Caused by a Dickeya sp. (ex Pectobacterium chrysanthemi) in Mainland China

Plant Disease ◽  
2009 ◽  
Vol 93 (5) ◽  
pp. 552-552 ◽  
Author(s):  
B. Li ◽  
W. Qiu ◽  
Y. Fang ◽  
G. L. Xie
Keyword(s):  
Mainland China ◽  
Stem Rot ◽  
Bacterial Suspension ◽  
Identification System ◽  
Microbial Identification ◽  
Embl Accession ◽  
Initial Symptoms ◽  
Leaf Tissues ◽  
Pectobacterium Chrysanthemi ◽  
Microbial Identification System

In December 2007, stem rot symptoms on orchids (Oncidium Gower Ramsey) were observed at a flower nursery in the Zhejiang Province of China. Initial symptoms were water-soaked lesions starting at the base of the stem. As these lesions expanded and elongated, the stem and leaf tissues became soft and watery. When examined with a microscope, cut edges of symptomatic stem and leaf tissues consistently exhibited bacterial streaming. The bacteria were isolated by streaking on nutrient agar (3). All isolates were gram-negative, facultative, anaerobic rods with peritrichous flagella. Infiltration of tobacco leaves (Nicotiana tabacum cv. Samsun) with the bacterial suspension of 108 CFU/ml resulted in typical hypersensitivity reactions within 24 h. Five representative isolates were further characterized by the Biolog Microbial Identification System, version 4.2 (Biolog Inc., Hayward, CA) and gas chromatography of fatty acid methyl esters (FAME) by the Microbial Identification System (MIDI Inc., Newark, DE) with aerobic bacterial library (TSBA50). The five isolates were identified as Erwinia chrysanthemi (Pectobacterium chrysanthemi) with a Biolog and FAME similarity index of 0.81 to 0.88 and 0.62 to 0.75, respectively. The transfer of P. chrysamthemi to a novel genus, Dickeya gen. nov., was recently proposed (2). The almost complete 16S rDNA sequence from Oncidium isolate SCH-01 (1,604 bp; EMBL Accession No. FM946179) was determined according to the method of Li et al. (1). A subsequent GenBank search showed that this isolate is 98% identical to that of type strain CFBP 1269T of Dickeya dadantii (EMBL Accession No. AF520707) and CFBP 1200T of Dickeya dianthicola (EMBL Accession No. AF520708). Nevertheless, species identification within genus Dickeya is still difficult since only a limited number of strains of each species have been characterized fully. Koch's postulates were completed with the inoculation of Oncidium seedlings with cell suspensions (108 CFU/ml) by a pinprick at the base of the stem. All five representative isolates induced stem rot similar to that observed in natural infections. No symptoms were noted on the control plants inoculated with sterilized distilled water by the same method. The bacterium was reisolated from symptomatic stems of Oncidium plants. To our knowledge, this is the first report of stem rot on Oncidium orchid in Mainland China caused by the bacterium formerly referred to as P. chrysanthemi, now proposed as Dickeya sp. References: (1) B. Li et al. J. Phytopathol. 154:711, 2006. (2) R. Samson et al. Int. J. Syst. Evol. Microbiol. 55:1415, 2005. (3) N. W. Schaad et al. Laboratory Guide for Identification of Plant Pathogenic Bacteria. 3rd ed. The American Phytopathological Society. St. Paul, MN, 2001.

scholarly journals First Report of Xanthomonas axonopodis Infecting Agapanthus in Florida

Plant Disease ◽  
2002 ◽  
Vol 86 (5) ◽  
pp. 562-562
Author(s):  
D. J. Norman ◽  
R. J. Henny ◽  
J. M. F. Yuen ◽  
E. R. Dickstein
Keyword(s):  
Fatty Acid Analysis ◽  
Identification System ◽  
Strictly Aerobic ◽  
Euphorbia Pulcherrima ◽  
Similarity Coefficients ◽  
Xanthomonas Axonopodis ◽  
Microbial Identification ◽  
Bedding Plant ◽  
Large Round ◽  
Dark Green

Agapanthus praecox subsp. orientalis, commonly called African lily or lily-of-the-Nile, bears large, round, blue or white flowers above attractive dark green foliage. Because of these horticultural features, this member of the family Liliaceae, has become a popular perennial bedding plant. For the past 2 years during warm wet periods, symptoms of chlorotic, water-soaked, leaf-streaks have been observed on agapanthus production in Florida. Round butyrus, bright yellow colonies were consistently isolated on nutrient agar. Bacteria were characterized as gram negative, catalase positive, motile, strictly aerobic, and not hydrolytic on starch. Using fatty acid analysis (FAME) and the MIDI Microbial Identification System with software version TSBA 3.90 (Microbial ID, Inc., Newark DE), three strains were further characterized and identified as Xanthomonas axonopodis with similarity coefficients to X. axonopodis pv. dieffenbachiae (0.907, 0.915, and 0.944) and to X. axonopodis pv. poinsetticola (0.912, 0.922, and 0.916). The three isolates were each inoculated on three plants each of agapanthus cv. Blue African lily, Dieffenbachiae maculata cv. Camille, and poinsettia, Euphorbia pulcherrima cv. PeterStar Red. Plants were sprayed with a suspension of each isolate at 1 × 108 CFU/ml, bagged for 24 h to raise humidity, and placed in a glasshouse for symptom development. Strains of X. axonopodis pv. poinsetticola (NZTCC 5779) and X. axonopodis pv. dieffenbachiae (X1718) were used as positive controls. Within 3 weeks, isolates from agapanthus produced leaf streaks on agapanthus plants, small, scattered, water-soaked lesions on dieffenbachia leaves, and no symptoms on poinsettia. No symptoms developed on the agapanthus plants when inoculated with either control strain. Both control strains formed lesions on leaves of their original host species. Xanthomonas was reisolated from treatments with symptomatic leaves. Plant inoculations were repeated with similar results. Although the agapanthus isolates were highly similar in FAME profiles to X. axonopodis pv. dieffenbachiae, symptoms produced on dieffenbachia were mild as compared with those produced by the dieffenbachia isolate. Therefore, these isolates may represent a distinct pathovar.

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