New Disease Reports (2011) 24, 10. [http://dx.doi.org/10.5197/j.2044-0588.2011.024.010]
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First report of Pseudomonas syringae pv. actinidiae on kiwifruit plants in Spain

G.M. Balestra*, M. Renzi and A. Mazzaglia

*balestra@unitus.it

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Received: 22 Jun 2011; Published: 07 Sep 2011

Keywords: bacterial plant disease

Bacterial canker caused by Pseudomonas syringae pv. actinidiae is the most harmful disease affecting kiwifruit (Actinidia spp.) cultivation worldwide reported so far. Reported in the 1980s in Asia (China, Japan, Korea), it was then described in the most important kiwifruit areas in other parts of the world (Italy, Portugal, France, New Zealand, Chile). The disease occurred on the main kiwi species (A. deliciosa and A. chinensis) and on different cultivars of kiwifruit. In 2011 the disease was observed during spring on two-year-old plants of cultivars of A. deliciosa (cv. Hayward) and of A. chinensis (cv. Jin Tao). Kiwifruit orchards with trees showing suspected symptoms were found located in Burgueira, Tomino Government, Provincia de Pontevedra - Galicia (Spain). The symptoms were similar to those recently reported in Portugal (Balestra et al., 2010) and characterised by typical symptoms on leaves (brown spots surrounded by yellow haloes), red browning on canes, with red sap production (Fig. 1). The disease incidence was estimated to be as high as 70 to 90% on the basis of the proportion of trees with evident symptoms in each orchard.

Bacterial colonies were isolated from infected leaves on nutrient agar containing 5% sucrose. Four representative isolates were Gram-negative, negative for oxidase, potato soft rot, arginine dehydrolase, presence of tyrosinase and urease, nitrate and fluorescent pigment production. They were positive for levan production, presence of catalase and induction of a hypersensitive response on tobacco cv. Virginia Bright (Lelliott & Stead, 1988). Pathogenicity was confirmed by spraying a bacterial suspension calibrated at 107 cfu/ml on two-year-old plants of A. deliciosa (cv. Hayward) and A. chinensis (cv. JinTao). The assay was conducted on ten plants. Leaf symptoms were observed within 15 days after inoculation. No symptoms were observed on control plants. Bacteria with morphological, biochemical and molecular characteristics identical to the original isolate were re-isolated from tissue showing symptoms. The isolates (PSA 827, PSA 828, PSA 829, PSA 830) selected for molecular identification were compared to P.s. pv. actinidiae reference strains (CFBP 7285, CFBP 7286, CFBP 7287, NCPPB 3739). Identification of the strains was confirmed by PCR amplification with two pairs of P.s. pv. actinidiae specific primers (Koh & Nou, 2002; Rees-George et al., 2010). This is the first report of P.s. pv. actinidiae on kiwifruit cultivars (A. deliciosa and A. chinensis) in Spain.

Figure1+
Figure 1: Field symptoms (brown spots surrounded by yellow haloes) caused by Pseudomonas syringae pv. actinidiae isolated in Spain on kiwifruit leaves of cv. Hayward (A) and cv. Jin Tao (B).
Figure 1: Field symptoms (brown spots surrounded by yellow haloes) caused by Pseudomonas syringae pv. actinidiae isolated in Spain on kiwifruit leaves of cv. Hayward (A) and cv. Jin Tao (B).

Acknowledgements

This study was partially supported by MIUR (60%) 2010 and by Regione Lazio, Department of Agriculture, projects.


References

  1. Balestra GM, Renzi M, Mazzaglia A, 2010. First report of bacterial canker of Actinidia deliciosa caused by Pseudomonas syringae pv. actinidiae in Portugal. New Disease Reports 22, 10. [http://dx.doi.org/10.5197/j.2044-0588.2010.022.010]
  2. Koh JK, Nou IS, 2002. DNA markers for identification of Pseudomonas syringae pv. actinidiae. Molecules and Cells, 13, 309-314.
  3. Lelliott RA, Stead DE, 1988. Methods for the Diagnosis of Bacterial Diseases of Plants. Oxford, UK: Blackwell Scientific.
  4. Rees-George J, Vanneste JL, Cornish DA, Pushparajah IPS, Yu J, Templeton MD, Everett KR, 2010. Detection of Pseudomonas syringae pv. actinidiae using polymerase chain reaction (PCR) primers based on the 16S-23S rDNA intertranscribed spacer region and comparison with PCR primers based on other gene regions. Plant Pathology 59, 453-464. [http://dx.doi.org/10.1111/j.1365-3059.2010.02259.x]

To cite this report: Balestra GM, Renzi M, Mazzaglia A, 2011. First report of Pseudomonas syringae pv. actinidiae on kiwifruit plants in Spain. New Disease Reports 24, 10. [http://dx.doi.org/10.5197/j.2044-0588.2011.024.010]

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