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

Plant Disease ◽  
2021 ◽  
Author(s):  
Huan-Yu Chen ◽  
Chun-Chi Lin ◽  
Chih-Wei Wang ◽  
NAI-CHUN LIN

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.

Plant Disease ◽  
2012 ◽  
Vol 96 (2) ◽  
pp. 286-286 ◽  
Author(s):  
N. Kuzmanović ◽  
A. Ćalić ◽  
M. Ivanović ◽  
K. Gašić ◽  
J. Pulawska ◽  
...  

In November 2010, a serious outbreak of crown gall disease was observed on 3-year-old grapevine (Vitis vinifera L.) cv. Cabernet Sauvignon grafted onto Kober 5BB rootstock in two commercial vineyards located in the South Banat District in Serbia. Large, aerial tumors were visible above the grafting point on grapevine trunks, and in most cases, the tumors completely girdled the trunk. From the gall tissues, white, circular, and glistening bacterial colonies were isolated on yeast mannitol agar medium. Eight, nonfluorescent, gram-negative, and oxidase-positive strains were isolated from seven tumor samples and selected for further identification. PCR assays with A/C′ (1) and VCF3/VCR3 (4) primers corresponding to the virD2 and virC genes yielded 224- and 414-bp fragments, respectively, confirming that the strains harbored the plasmid responsible for pathogenicity. The strains were differentiated to the species/biovar level with a multiplex PCR assay targeting 23S rRNA gene sequences (3) and were identified as Agrobacterium vitis. The 16S rDNA gene sequence from one isolate (GenBank Accession No. JN185718) showed 99% identity to the sequences of A. vitis previously deposited in NCBI GenBank database. The physiological and biochemical test results corresponded to the results of genetic analysis (2). The strains grew at 35°C and in nutrient broth supplemented with 2% NaCl. They were negative in 3-ketolactose, acid clearing on PDA supplemented with CaCO3, and ferric ammonium citrate tests; nonmotile at pH 7.0; pectolytic at pH 4.5; utilized citrate; produced acid from sucrose and alkali from tartarate. Pathogenicity was confirmed by inoculation of three plants per bacterial strain on grapevine cv. Cabernet Franc and on a local cultivar of tomato (Lycopersicon esculentum L.). The plants were inoculated on the stem by pricking one to three times through a drop of inoculum (108 CFU/ml) at three inoculation sites. Sterile distilled water was used as a negative control. Inoculated plants were maintained in a greenhouse at 24 ± 3°C. Typical tumors developed at the inoculation sites on tomatoes 3 weeks after inoculation and on grapevine 6 weeks after inoculation. No symptoms were observed on the control plants. Bacteria were reisolated from tumorigenic tissues and identified as pathogenic A. vitis by PCR. Crown gall disease was sporadically observed in vineyards in Serbia in previous years, but did not cause significant damage. Therefore, the causal agent was not studied in detail. To our knowledge, this is the first report of A. vitis determined as the causal agent of grapevine crown gall in Serbia. References: (1) J. H. Haas et al. Appl. Environ. Microbiol. 61:2879, 1995. (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. (3) J. Pulawska et al. Syst. Appl. Microbiol. 29:470, 2006. (4) K. Suzaki et al. J. Gen. Plant Pathol. 70:342, 2004.


Plant Disease ◽  
2013 ◽  
Vol 97 (6) ◽  
pp. 836-836 ◽  
Author(s):  
S. Chebil ◽  
R. Fersi ◽  
S. Chenenaoui ◽  
E. Abdellatif ◽  
G. Durante ◽  
...  

Since October 2011, a serious outbreak of crown gall disease was observed on 1- and 2-year-old grapevines (Vitis vinifera L.) cv. Superior Seedless in several vineyards located in the region of Regueb in the center of Tunisia. Fifty isolates of Agrobacterium were isolated on a tartrate medium from galls of affected plants. To prepare template DNA, cell suspensions were lysed in 0.25% sodium-azide (NaN3) buffer prepared in 1% Triton X-100 by heating the samples at 95°C for 10 to 15 min (1). The strains were differentiated using a multiplex PCR assay with a combination of VIRFF1/VIRFR2 and VIRD2S4F716/VIRD2S4R1036 primers (2), which detect regions of virF and virD2 genes, respectively, in A. vitis strains carrying octopine or nopaline Ti plasmids and A. vitis vitopine strains. In order to differentiate A. vitis strains from A. tumefaciens strains, PGF/PGR (4), a polygalacturonase specific primer set, was added to the mixture in multiplex PCR. The isolates segregated into three main groups. The first group carries octopine type Ti plasmids, the second carries vitopine type Ti plasmids, and the third group carries both octopine and vitopine type Ti plasmids. The polygalacturonase gene sequence from 10 isolates showed 94 to 97% identity to the sequences of A. vitis previously deposited in the NCBI GenBank database (Accession No. CP000633.1gb). The biochemical test results corresponded to the results of genetic analysis. The ability to aerobically convert lactose to 3-ketolactose was tested by spotting bacteria onto medium containing lactose and flooding plates with a layer of Benedict's reagents after incubation at 28°C for 48 h. Acid production from glucose was tested by spotting bacterial strains onto potato dextrose agar (PDA) medium supplemented with CaCO3. Alkali production from L-tartrate was tested by streaking bacteria on AB minimal medium supplemented with L-tartrate and growth in salt medium was tested by streaking on nutrient broth supplemented with 2% NaCl. All isolates except one were negative in 3-ketolactose. They were negative in acid clearing on PDA-CaCO3, grew in 2% NaCl, and produced alkali from tartarate. Pathogenicity of all 50 strains was tested on 1-month-old tomato plants (Lycopersicum esculentum cv. Riograndi). Plants were inoculated on the stem by pricking one to three times through a drop of inoculum (108 CFU/ml) at three inoculation sites. Sterile distilled water was used as control treatment. Plants were grown for 4 weeks at 23 ± 3°C and symptoms were recorded. Typical tumors developed at the inoculation sites and no symptoms were observed on the control plants. In Tunisia, crown gall disease was observed only on stone fruit trees and only A. tumefaciens Biovar 1 have been reported and assigned to four genomic species G4, G6 G7, and G8 basically on the recA sequencing (3). To our knowledge, this is the first report of A. vitis determined as the causal agent of grapevine crown gall in Tunisia. References: (1) A. Abolmaaty et al. Microbios 101:181, 2000. (2) F. Bini et al. Vitis 47:181, 2008. (3) D. Costechareyre et al. Microb. Ecol. 60:862, 2010. (4) E. Szegedi and S. Bottka. Vitis 41:37, 2002.


Plant Disease ◽  
2013 ◽  
Vol 97 (5) ◽  
pp. 685-685
Author(s):  
Y. J. Wang ◽  
Y. Y. He ◽  
Z. Xie ◽  
L. Q. Zhang

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.


Plant Disease ◽  
2016 ◽  
Vol 100 (2) ◽  
pp. 515-515 ◽  
Author(s):  
T. Perović ◽  
M. Renzi ◽  
A. Mazzaglia ◽  
G. M. Balestra

Nature Plants ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 22-27 ◽  
Author(s):  
Ursula Fürst ◽  
Yi Zeng ◽  
Markus Albert ◽  
Anna Kristina Witte ◽  
Judith Fliegmann ◽  
...  

2016 ◽  
Vol 82 (18) ◽  
pp. 5542-5552 ◽  
Author(s):  
Hanna Faist ◽  
Alexander Keller ◽  
Ute Hentschel ◽  
Rosalia Deeken

ABSTRACTCrown gall disease of grapevine is caused by virulentAgrobacteriumstrains and establishes a suitable habitat for agrobacteria and, potentially, other bacteria. The microbial community associated with grapevine plants has not been investigated with respect to this disease, which frequently results in monetary losses. This study compares the endophytic microbiota of organs from grapevine plants with or without crown gall disease and the surrounding vineyard soil over the growing seasons of 1 year. Amplicon-based community profiling revealed that the dominating factor causing differences between the grapevine microbiota is the sample site, not the crown gall disease. The soil showed the highest microbial diversity, which decreased with the distance from the soil over the root and the graft union of the trunk to the cane. Only the graft union microbiota was significantly affected by crown gall disease. The bacterial community of graft unions without a crown gall hosted transient microbiota, with the three most abundant bacterial species changing from season to season. In contrast, graft unions with a crown gall had a higher species richness, which in every season was dominated by the same three bacteria (Pseudomonassp.,Enterobacteriaceaesp., andAgrobacterium vitis). Forin vitro-cultivated grapevine plantlets,A. vitisinfection alone was sufficient to cause crown gall disease. Our data show that microbiota in crown galls is more stable over time than microbiota in healthy graft unions and that the microbial community is not essential for crown gall disease outbreak.IMPORTANCEThe characterization of bacterial populations in animal and human diseases using high-throughput deep-sequencing technologies, such as 16S amplicon sequencing, will ideally result in the identification of disease-specific microbiota. We analyzed the microbiota of the crown gall disease of grapevine, which is caused by infection with the bacterial pathogenAgrobacterium vitis.All otherAgrobacteriumspecies were found to be avirulent, even though they lived together withA. vitisin the same crown gall tumor. As has been reported for human cancer, the crown gall tumor also hosted opportunistic bacteria that are adapted to the tumor microenvironment. Characterization of the microbiota in various diseases using amplicon sequencing may help in early diagnosis, to serve as a preventative measure of disease in the future.


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