bombacopsis quinata: a new host for oidiopsis haplophylli in brazil

Plant Pathology

(2007)

56

, 1040 Doi: 10.1111/j.1365-3059.2007.01636.x

© 2007 The Authors

1040

Journal compilation © 2007 BSPP

Blackwell Publishing Ltd

Association of

Candidatus

Phytoplasma asteris with little leaf disease of desert rose

S. K. Raj*, M. S. Khan, S. Kumar and S. K. Snehi

Molecular Virology, National Botanical Research Institute, Lucknow-226 001, India

Desert rose (

Adenium obesum

) of the Apocynaceae family, is an exoticornamental plant from warm climates, grown for its attractive fleshy stem,leaves and bright colourful flowers. Little leaf-like symptoms wereobserved in May–August 2006 on two plants being maintained in a housegarden at Lucknow, India. Symptoms included phyllody and excessivedevelopment of internodes resulting in little leaves. To assay for theassociation of phytoplasma with the little leaf symptoms, total DNA wasisolated from infected leaf tissues and from an apparently healthy plant.PCR was performed with P1/P6 universal primers specific to the 16S rRNAgene (Deng & Hiruki, 1991). In addition, nested PCR was carried out withprimers R16F2n/R16R2n (Gundersen & Lee, 1996) using the first roundPCR product as the template. DNA fragments of the expected sizes(~1·5 kb and 1·2 kb respectively) were obtained from the infected plantsamples but not from the apparently healthy one. The identity of the PCRamplicons was confirmed by Southern blot hybridization using a probeprepared from a clone of the chilli little leaf phytoplasma reported earlier(GenBank Acc. No. DQ343288), which showed strong hybridizationunder high stringency conditions.

The 1·2 kb amplicon was sequenced and the sequence data depositedin GenBank Acc. No. EF159729. The sequence shared 99% similaritywith the 16S ribosomal RNA gene of Barley deformation, Aster yellows,

Valeriana yellows, Onion yellows, Silene virescence and Chilli littleleaf phytoplasmas (GenBank Acc. Nos. AY734453, AY665676, AY102274,AP006628, AY744070 and DQ343288 respectively), which belong to

Candidatus

Phytoplasma asteris (16SrI Aster yellows group).A literature survey revealed reports of natural infection of desert rose

with

Cucumber mosaic virus

(Baker

et al

., 2003) and

Tomato spotted wiltvirus

(Adkins & Baker, 2005), but not with a phytoplasma. This is the firstreport of

Candidatus

Phytoplasma asteris associated with little leaf diseaseof desert rose in India or elsewhere.

References

Adkins S, Baker CA, 2005.

Tomato spotted wilt virus

identified in desert rose in Florida.

Plant Disease

89

, 526.Baker CA, Achor D, Adkins S, 2003.

Cucumber mosaic virus

diagnosed in desert rose in Florida.

Plant Disease

87

, 1007.Deng S, Hiruki D, 1991. Amplification of 16S rRNA genes from culturable and

nonculturable mollicutes.

Journal of Microbiological Methods

14

, 53–61.Gundersen DE, Lee IM, 1996. Ultrasensitive detection of phytoplasmas by

nested-PCR assays using two universal primer pairs.

Phytopathologia Mediterranea

35

, 144–51.

*E-mail: skraj2@rediffmail.com

Accepted 22 December 2006 at www.bspp.org.uk/ndr where figures relating to this paper can be viewed

Plant Pathology

(2007)

56

, 1040 Doi: 10.1111/j.1365-3059.2007.01639.x

XXX

New Disease Reports

New Disease ReportsAUTHORS RUNNING HEAD:

New Disease Reports

NEW DISEASE REPORT

Bombacopsis quinata

: a new host for

Oidiopsis haplophylli

in Brazil

B. A. Halfeld-Vieira*, L. M. M. Ferreira and K. L. Nechet

Embrapa Roraima, BR 174, km 8, Distrito Industrial, CP 133, 69301-970, Boa Vista-RR, Brazil

Bombacopsis quinata

(Spiny Cedar, Cedro-Doce, Pochote, Saqui-Saqui,Cedro Espino) is a fast-growing native tree from central and northernSouth America, and grows naturally in a forest ecosystem in Roraima,Brazil. This valuable species is used for wood exploration (Barbosa, 1990)and more recently has been cultivated in an agroforestry system.

In April 2006 at Mucajaí, Roraima, small leaf spots were observed andsymptoms ranged from mild chlorosis to more severe necrotic spots. Earlysenescence of affected leaves was common. Microscopic examinationof the fungus on the abaxial leaf surface revealed conidiophores(180–250

×

7

µ

m, 3–4 septa, hyaline, occasionally branched) emergingthrough stomata. Conidia were dimorphic, hyaline and smooth; primaryconidia were lanceolate, 52–81

×

15–18

µ

m, mean length-to-width ratio3·9; secondary conidia cylindrical 52–65

×

13–15

µ

m, mean length-to-width ratio 4·0. The teleomorph was absent in these observations. Theanamorphic structures conform most closely to

Oidiopsis haplophylli

(Braun, 1987; Braun

et al

., 2002).

Leveillula taurica

, the true state of

Oidiopsis haplophylli

, has a wide

host range covering many plant families. However, until now the pathogenhas only been recorded on a single Bombacaceae species,

Adansoniadigitata

(Ebbels & Allen, 1979). This is the first record of

Oidiopsishaplophylli

on

Bombacopsis quinata

.

References

Barbosa RI, 1990. Análise do setor madeireiro do Estado de Roraima.

Acta Amazonica

20

, 193–209.Braun U, 1987. A monograph of the Erysiphales (powdery mildews).

Beihefte zur Nova Hedwigia

89

, 1–700.Braun U, Cook RTA, Inman AJ, Shin H-D, 2002. The taxonomy of the

powdery mildew fungi. In: Bélanger RR, Bushnell WR, Dik AJ, Carver TLW, eds.

The Powdery Mildews: A Comprehensive Treatise

. St. Paul, MN, USA: APS Press, 13–55.

Ebbels DL, Allen DJ, 1979.

A Supplementary and Annotated List of Plant Diseases, Pathogens and Associated Fungi in Tanzania

. Kew, UK: Commonwealth Mycological Institute.

*E-mail: halfeld@cpafrr.embrapa.br

Accepted 4 January 2007 at www.bspp.org.uk/ndr where figures relating to this paper can be viewed