First report of crown gall of apricot (Prunus armeniaca) caused by Agrobacterium tumefaciens in Turkey

Soapberry (Sapindus delavayi (Franch.) Radlk.,) plants are widely grown as shade trees in the subtropical to tropical regions of China. In July 2011, large, aerial galls were observed on the above-ground trunks of 5-year-old soapberry plants in two commercial nursery gardens located in Zhejiang Province. Disease incidence was estimated to be 75%. The galls varied in weight from 2 to 24 g and in texture from soft and spongy to hard, and in some cases, the galls completely girdled the trunk. The trees with galls exhibited poor growth compared with healthy trees. Isolations from the grinded and macerated galls yielded nearly pure white, circular, and glistening bacterial colonies on Roy Sauer medium (2). Six random colonies from different galls were selected for bacterial identification, and showed the same morphological, physiological, and biochemical characters and 16S rDNA sequences. All six isolates (isolate SD01 to SD06) were gram negative, rod-shaped bacteria. Carbon source utilization testing with the Biolog GN Bacterial Identification System (version 3.50) confirmed the bacteria as Agrobacterium tumefaciens with a similarity of 0.90. The most-parsimonious tree from the maximum parsimony analysis (PHYLIP package, version 3.68, 500 replicates) of bacterial 16S rDNA gene sequences showed that A. tumefaciens SD01 (GenBank Accession No. JX997939) clustered phylogenetically most closely (99.5% similarity) with A. tumefaciens C58 (AE007870.2). Pathogenicity was confirmed by injecting 3- to 5-week old tomato and sunflower plants and 2-year-old soapberry with approximately 5 μl of the bacterial suspension (108 CFU/ml) in sterile, distilled water. Sterile distilled water was used as a negative control. Ten plants of each treatment were inoculated. Inoculated plants were then transferred to a greenhouse at 25°C. Typical tumors developed at the inoculation sites on tomatoes and sunflower plants 3 weeks after inoculation and on soapberry 6 weeks after inoculation. No symptoms were observed on the control plants. The bacteria that were readily reisolated from the inoculated plants exhibited the same morphological, physiological characters and 16S rDNA sequence as the original culture and were confirmed as A. tumefaciens, fulfilling Koch's postulates. A. tumefaciens is endemic to China and has a very wide host range (1). However, crown gall of soapberry has never been found in China and other countries. To our knowledge, this is the first report of A. tumefaciens on soapberry plants in China. References: (1) M. A. Escobar and A. M. Dandekar. Trends Plant Sci. 8:380, 2003. (2) L. W. Moore et al. Page 17 in: Laboratory Guide for Identification of Plant Pathogenic Bacteria. 3rd ed. N. W. Schaad et al., eds. The American Phytopathological Society, St. Paul, MN, 2001.

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First Report of Crown Gall Caused by Agrobacterium tumefaciens on Euphorbia esula/virgata in Europe

Plant Disease ◽

10.1094/pdis-92-12-1710a ◽

2008 ◽

Vol 92 (12) ◽

pp. 1710-1710 ◽

Cited By ~ 1

Author(s):

A. J. Caesar ◽

R. T. Lartey

Keyword(s):

Agrobacterium Tumefaciens ◽

Crown Gall ◽

The United States ◽

Euphorbia Esula ◽

Ammonium Citrate ◽

Ferric Ammonium Citrate ◽

Economic Losses ◽

East Central ◽

First Report ◽

Soil Line

Hypertrophy and hyperplasia resembling crown galls were found on roots of Euphorbia esula/virgata at a single site in east-central Hungary in 2005. E. esula/virgata, known as leafy spurge in North America, is an invasive species causing substantial economic losses to the value of grazing lands in the Northern Great Plains of the United States and is the target of biological control. E. esula/virgata is widely distributed throughout Eurasia and is found on ditch banks, along roadsides, and in other noncultivated areas in its native range. Large galls on roots resembling crown gall were first noted in 1992 on plants collected for phylogenetic studies from three locations in east-central Hungary. One of these sites was relocated during a 2005 survey and galls were collected from infected plants. Galls were diced and incubated overnight in tubes containing 3 ml of sterile water at room temperature (20 to 25°C). The supernatant was streaked onto plates of potato dextrose agar (PDA), medium 1A, medium 2E, and Roy/Sasser medium. After 7 days, colonies were picked and streaked and subsequently purified on PDA. Of 104 isolates used to inoculate three sunflower plants each (by puncturing roots just below the soil line with a sterile dissecting needle holding a drop of fluid matrix containing bacterial cells), 35 caused galls. Thirty-three isolates were randomly selected from the 104 and used to inoculate three tomato plants each at the soil line. Seventeen caused galls, including two isolates that did not cause galls on sunflower. Finally, none of 20 randomly selected isolates caused galls on kalanchoe plants (Kalanchoe blossfeldiana). Three isolates, which formed the largest galls on sunflower, were used to inoculate five plants of E. esula/virgata growing in a 1:1:1 (peat/sand/Bozeman silt loam) potting mix. The tests were repeated. Galls were visible on inoculated plants within 6 weeks. Diagnostic biochemical tests done prior to and after reisolation indicated that the causal agent was Agrobacterium tumefaciens, which differed from A. rhizogenes in the production of alkali from litmus milk, a positive reaction for the ferric ammonium citrate and 3-ketolactose tests, and negative reactions for tests to detect the production of acid from erythritol and alkali from malonic, l-tartaric, and mucic acid. The three isolates of A. tumefaciens from E. esula/virgata had identical sequences and clustered most closely (99.8 to 99.9% similarity) with five isolates of A. tumefaciens from Tibet and Japan on the basis of cluster analysis using 16S rRNA sequences. Crown gall of E. esula/virgata has also been found in Montana and western North Dakota, and isolates were identified as A. tumefaciens biovars 1 and 2 (1) (the latter is now known as A. rhizogenes). To our knowledge, this the first report of crown gall on E. esula/virgata in Europe. Reference: (1) A. J. Caesar. Plant Dis. 78:796, 1994.

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First report of Agrobacterium tumefaciens causing crown gall disease of roselle (Hibiscus sabdariffa L.) in Taiwan

Plant Disease ◽

10.1094/pdis-05-21-1007-pdn ◽

2021 ◽

Author(s):

Huan-Yu Chen ◽

Chun-Chi Lin ◽

Chih-Wei Wang ◽

NAI-CHUN LIN

Keyword(s):

Agrobacterium Tumefaciens ◽

Sequence Analysis ◽

Crown Gall ◽

Causal Agent ◽

Reca Gene ◽

Bacterial Suspension ◽

Hibiscus Sabdariffa ◽

Agrobacterium Vitis ◽

First Report ◽

Crown Gall Disease

Roselle (Hibiscus sabdariffa L.) plants, whose calyces are used for production of beverages or jams, are mainly cultivated in Taitung County of eastern Taiwan. Since 2016, large crown galls were observed on the roselle plants in the commercial plantations at Taimali and Jinfong Townships of Taitung County. A follow-up survey in July and August of 2017 revealed spreading of this disease to the neighboring areas including Beinan and Dawu Townships. Disease incidence was estimated to be 0.6-10%. Galls of varying sizes (2-15 cm in diameter) were usually found on the roots and crowns of the roselle plants, starting with small swellings at the infection sites. Galls were light-colored, and smooth and tender in texture at the early stage, but later turned dark-colored, and appeared rough and woody. In some cases, adventitious roots extruding from the larger crown galls could be seen. Isolation of the causal agent was performed by quadrantally streaking bacterial suspension made from surface-sterilized, macerated galls on trypticase soy agar (TSA). After incubating at 28°C for 5 days, single colonies were transferred onto new TSA plates for further cultivation at 28°C. Finally, circular, convex, viscous and milky white colonies with smooth surface similar to colony morphology of Agrobacterium tumefaciens C58 were obtained for further identification. First, all six candidate isolates (TZ-1, TL1-2, TL2-1, TD1-1, TD1-24 and TD2-1) were identified as Agrobacterium spp. using the partial sequences of the 16S rRNA gene (accession numbers MW205820 to MW205825 in the GenBank database). The selected isolates also showed some biochemical and physiological characteristics similar to A. tumefaciens, including oxidase positive, growth at 35°C and in 2% NaCl, and alkalinity from litmus milk. Moreover, they were tested negative for utilization of citrate and acid production on potato dextrose agar (PDA) supplemented with calcium carbonate. Under a transmission electron microscope, the bacterium was rod-shaped and possessed peritrichous flagella. By means of multiplex PCR using primers designed for differentiation of Agrobacterium rubi, Agrobacterium vitis and Agrobacterium biovars 1 and 2, a 184 bp product was detected in all six isolates, indicating that they all belong to Agrobacterium biovar 1. Furthermore, the recA allele of each isolate was PCR amplified using primers F2898/F2899, and recA sequence analysis assigned all six isolates to A. tumefaciens genomospecies G7 (GenBank accession numbers MZ570905-MZ570910). Pathogenicity assay was carried out by inoculating the stems of 2-week-old roselle seedlings through wounds made with a sterile needle with bacteria on it. The inoculated seedlings were kept in plastic bags to maintain high humidity. Symptoms similar to those observed in the field developed at the inoculation sites after 7 days, and Koch’s postulates were fulfilled when the bacteria re-isolated from the galls were also identified as A. tumefaciens genomospecies G7 using recA gene sequence analysis. To our knowledge, this is the first report of crown gall disease caused by A. tumefaciens on Hibiscus sabdariffa in Taiwan. This disease may potentially damage the roselle industry if no action is taken to stop its spreading. Identification of the causal agent of roselle crown gall disease could help us further investigate its ecology and develop integrated pest management strategies for prevention of this disease in the future.

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First Report of Agrobacterium tumefaciens as a Causal Agent of Crown Gall on Grapevine in Montenegro

Plant Disease ◽

10.1094/pdis-07-15-0730-pdn ◽

2016 ◽

Vol 100 (2) ◽

pp. 515-515 ◽

Cited By ~ 1

Author(s):

T. Perović ◽

M. Renzi ◽

A. Mazzaglia ◽

G. M. Balestra

Keyword(s):

Agrobacterium Tumefaciens ◽

Crown Gall ◽

Causal Agent ◽

First Report

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Crown Gall Resistance in Accessions of 20 Prunus Species

HortScience ◽

10.21273/hortsci.34.2.326 ◽

1999 ◽

Vol 34 (2) ◽

pp. 326-330 ◽

Cited By ~ 24

Author(s):

F.A. Bliss ◽

P.L. Schuerman ◽

A.A. Almehdi ◽

A.M. Dandekar ◽

N. Bellaloui

Keyword(s):

Agrobacterium Tumefaciens ◽

Crown Gall ◽

Prunus Armeniaca ◽

Prunus Species ◽

Sources Of Resistance ◽

Lateral Branches ◽

Important Disease

Crown gall is an important disease of many fruit and nut crops, but little is known about sources of resistance. We screened germplasm from Prunus armeniaca L., P. angustifolia Marsh., P. argentia L., P. avium L., P. besseyi Bailey, P. bokhariensis Schneid., P. brigantica L., P. cerasifera Ehrh., P. cerasus L., P. dulcis (Mill.) D.A. Webb, P. fruiticosa Pall., P. hortulana Bailey, P. insititia L., P. japonica Thunb., P. mahaleb L., P. persica (L.) Batsch, P. serotina Ehrh., P. simonii Carr., P. sogdiana L., and P. webbii (Spach) Vieh. When either main stems or lateral branches of seedlings were inoculated with strains K12 and C58 of Agrobacterium tumefaciens (Smith and Townsend) Conn., the incidence of resistance was less than 10% except in some accessions of P. mahaleb L. where up to 30% of the plants were resistant. Some resistant plants were identified in other species, with P. insititia L. being the most promising. Symptoms based on presence and size of galls should be allowed to develop for up to 90 days after inoculation to reduce the likelihood of misclassifying plants as resistant when they are slightly susceptible.

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