New Disease Reports
New Disease Reports (2009) 19, 3.
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First report of 16SrII ‘Candidatus Phytoplasma aurantifolia’ infecting chilli and tamarillo in Indonesia

R. Harling 1*, Y. Arocha 1,2, V. Harju 3, C. Tobing 4, E. Boa 1, P. Kelly 1 and R. Reeder 1

*plantclinic@cabi.org

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Accepted: 18 Feb 2009

Chilli pepper (Capsicum spp.) and tamarillo (Solanum [Cyphomandra] betaceum) are important cash crops in Indonesia. Smallholder farm fields around Bunuraya area, North Sumatera, were visited in September 2007. Symptoms of stunting, severe leaf mottling and bunching of small mottled leaves were observed in chilli (Fig. 1) and tamarillo (Fig. 2) with up to 100% of plants affected.

Leaf samples from randomly collected symptomatic chilli and tamarillo were assayed by electron microscopy and ELISA with negative results for a number of viruses likely to infect these hosts, including Pepper mild mottle virus, Tobacco and Tomato mosaic virus, Cucumber mosaic virus, Impatiens necrotic spot virus, Tomato spotted wilt virus, Alfalfa mosaic virus, and generic potyviruses and begomoviruses.

As phytoplasmas have been associated with diseases in chilli (Khan & Raj, 2006; Lebsky & Poghosyan, 2007), samples were indexed by a nested PCR using phytoplasma 16S rDNA universal primers (R16F2m/R1 followed by fU5/rU3), RFLP, and sequencing. PCR amplicons and identical RFLP profiles (HaeIII, RsaI and AluI) were obtained for symptomatic tamarillo (3/4) and chilli (4/4), but not for asymptomatic samples. PCR products of a representative tamarillo and chilli were purified and sequenced (www.dnaseq.co.uk). The phytoplasma 16S rDNA sequences from chilli (EU273881) and tamarillo (EU273882) were 99% identical to each other, and to members of the group 16SrII, ‘Candidatus Phytoplasma aurantifolia’.

Previous phytoplasma reports in Indonesia are associated with legume witches’ broom (Roechan et al., 1978), and Kalimantan coconut wilt (Warokka et al., 2006), but not from group 16SrII. To our knowledge, this is the first report of group 16SrII infecting chilli and tamarillo in Indonesia, and the first world report for tamarillo. As both infected crops were found growing in the same locality, this may suggest a common vector for transmission of the phytoplasma.

Figure1+
Figure 1: Severe stunting with small, bunched leaves at the top observed in chilli
Figure 1: Severe stunting with small, bunched leaves at the top observed in chilli
Figure2+
Figure 2: Tamarillo showing reduced leaf size and leaf yellowing
Figure 2: Tamarillo showing reduced leaf size and leaf yellowing

Acknowledgements

Work in the UK was done under Defra Plant Health Licence no. PHL 174B/4612(09/20003).Thanks to Dr Mohamad Roff Mohd Noor, Horticulture Research Centre, Kuala Lumpur, Malaysia for helping with field diagnosis.

References

  1. Khan MS, Raj SK, 2006. First report of molecular detection of an Aster yellows phytoplasma ('Candidatus Phytoplasma asteris') isolate infecting chilli (Capsicum annuum) in India. Plant Pathology 55, 822.
  2. Lebsky V, Poghosyan A, 2007. Phytoplasma associated diseases in tomato and pepper in the state of BCS, Mexico: a brief overview. Bulletin of Insectology 60, 131-132.
  3. Roechan M, Saleh N, Suguiura M, Hibino H, 1978. Identity of mycoplasma-like agents of legume witches' broom in Indonesia. Contributions from the Central Research Institute for Agriculture Bogor 41, 1–11.
  4. Warokka S, Jones P, Dickinson M, 2006. Detection of phytoplasmas associated with Kalimantan wilt disease of coconut by the polymerase chain reaction. Jurnal Littri 12, 154 – 160.
This report was formally published in Plant Pathology

©2009 The Authors