New Disease Reports
New Disease Reports (2012) 26, 23. [http://dx.doi.org/10.5197/j.2044-0588.2012.026.023]
Get pdf (513 KB)
Next > < Prev

First report of the natural occurrence of group 16SrII 'Candidatus Phytoplasma aurantifolia' in two Solanum species in Iran

S. Samavi 1, M.M. Faghihi 1*, H. Hasanzadeh 1, A.N. Bagheri 1, M. Salehi 2 and P. Sotoudehnia 1

*mm.faghihi@yahoo.com

Show affiliations

Received: 26 Jun 2012; Published: 16 Nov 2012

Keywords: Solanum nigrum, Solanum surattense, Peanut witches' broom phytoplasma group

A survey for phytoplasma was carried out in citrus orchards in Hormozgan province of Iran in 2009 to assess the presence of 'Candidatus Phytoplasma aurantifolia' in non-citrus hosts. Symptoms of witches' broom, little leaf, short internode and yellowing were observed in Solanum nigrum (Fig. 1) and S. surattense (Fig. 2). S. nigrum (black nightshade) is an annual plant and one of the most cosmopolitan herb species (Edmonds & Chweya, 1997). The other medicinal herb, S. surattense, is highly polymorphic in phenotype but characteristically with scattered stellate hairs and prickly stem (Heiser, 1969). Phytoplasma DNA was detected in symptom-bearing plants using a nested polymerase chain reaction (PCR) assay. For each plant, total DNA was extracted separately from 0.5 g of leaf midribs of four symptom-bearing and two symptomless plants using a modified CTAB protocol (Doyle & Doyle, 1990). DNA samples were analysed with phytoplasma universal 16S rDNA primers, P1/P7 for direct PCR primers and R16F2n/R16R2 for the nested reaction, which yielded PCR products of approximately 1800 and 1250 bp, respectively. The 1800 and 1250 bp PCR products were amplified from all the symptom-bearing but not from the healthy plants, nor from the negative control. The nested PCR products were cloned (InsTAclone PCR kit K1214, Fermentas, Lithuania) and sequenced. BLAST search revealed that the obtained 16S rDNA sequences of the S. nigrum (GenBank Accession No. GQ866886) and S. surattense (GU550504) phytoplasmas shared 99% of nucleotide identity with each other and with the 16S rDNA sequences of members of the group 16SrII, 'Ca. P. aurantifolia' formerly 'Peanut witches' broom'. This is the first report of natural occurrence of phytoplasmas in S. nigrum and S. surattense in Iran. Salehi et al, (2002) proved dodder greenhouse transmission of a 'Ca. P. aurantifolia' to Solanum species, including S. nigrum, S. integrifolium and S. melongena. However, results from our study suggest that S. nigrum and S. surattense may play a role as natural intermediate hosts for the 16SrII phytoplasmas in the Hormozgan province of Iran.  

Figure1+
Figure 1: Symptoms of witches'-broom, proliferation with shortened internodes and chlorotic little leaf on Solanum nigrum in Hormozgan, Iran.
Figure 1: Symptoms of witches'-broom, proliferation with shortened internodes and chlorotic little leaf on Solanum nigrum in Hormozgan, Iran.
Figure2+
Figure 2: Symptoms of little leaf and short internodes on Solanum surattense plant (right) compared with a healthy plant (left).
Figure 2: Symptoms of little leaf and short internodes on Solanum surattense plant (right) compared with a healthy plant (left).
Figure3+
Figure 3: Phylogenetic tree constructed by DNAMAN software (version 4.0.1.1), based on the 16S rDNA sequences of the Solanum nigrum and S. surattense phytoplasmas, and other reference phytoplasmas from GenBank. Bootstrap values are shown on branches. Spiroplasma citri (AM157768) was used as the outgroup to root the tree. 'Ca. Phytoplasma' stands for ‘Candidatus Phytoplasma sp.’
Figure 3: Phylogenetic tree constructed by DNAMAN software (version 4.0.1.1), based on the 16S rDNA sequences of the Solanum nigrum and S. surattense phytoplasmas, and other reference phytoplasmas from GenBank. Bootstrap values are shown on branches. Spiroplasma citri (AM157768) was used as the outgroup to root the tree. 'Ca. Phytoplasma' stands for ‘Candidatus Phytoplasma sp.’

Acknowledgements

The authors are grateful to Dr. Majeed Askari Seyahooei forhis valuable suggestions. This work was supported by Hormozgan Agriculture and Natural Resources Research Center, Bandar Abbas, Iran.

References

  1. Doyle JJ, Doyle JL, 1990. Isolation of plant DNA from fresh tissue. Focus 12, 13-15.
  2. Edmonds JM, Chweya, JA. 1997. Black nightshades: Solanum nigrum L. and related species. Rome, Italy: International Plant Genetic Resources Institute.
  3. Heiser CB, 1969. The Wonderberry. In: Freeman WH, eds. Nightshades - Paradoxical Plants. San Francisco, USA: Freeman and Co, 62-105.
  4. Salehi M, Izadpanah K, Taghizadeh M. 2002. Witches' broom disease of lime in Iran: New distribution areas, experimental herbaceous hosts and transmission trials. In: Proceedings 15th Conference of International Organisation of Citrus Virologists (IOCV), 2002, Riverside, CA, USA, 293-296.
To cite this report: Samavi S, Faghihi MM, Hasanzadeh H, Bagheri AN, Salehi M, Sotoudehnia P, 2012. First report of the natural occurrence of group 16SrII 'Candidatus Phytoplasma aurantifolia' in two Solanum species in Iran. New Disease Reports 26, 23. [http://dx.doi.org/10.5197/j.2044-0588.2012.026.023]

©2012 The Authors