African Journal of
Biotechnology

  • Abbreviation: Afr. J. Biotechnol.
  • Language: English
  • ISSN: 1684-5315
  • DOI: 10.5897/AJB
  • Start Year: 2002
  • Published Articles: 12485

Full Length Research Paper

Ultrastructures of Candidatus Liberibacter asiaticus and its damage in huanglongbing (HLB) infected citrus

Hajivand Shokrollah1*, Thohirah Lee Abdullah1, Kamaruzaman Sijam2 and Siti Nor Akmar Abdullah3
1Departments of Crop Science, Faculty of Agriculture, University Putra Malaysia, 43400 Serdang, Selangor Darul Ehsan, Malaysia. 2Department of Plant Protection, Faculty of Agriculture, University Putra Malaysia, 43400 Serdang, Selangor Darul Ehsan, Malaysia. 3Department of Agriculture Technology, Faculty of Agriculture, University Putra Malaysia, 43400 Serdang, Selangor Darul Ehsan, Malaysia.
Email: [email protected]

  •  Accepted: 06 July 2010
  •  Published: 06 September 2010

Abstract

Candidatus Liberibacter asiaticus is not cultured in media and there is insufficient information on the movement of the pathogen in citrus plants. Samples were collected from infected citrus plants grown in Ulu Pakar, Terengganu, Malaysia and they show typical symptoms of the huanglongbing (HLB) disease. Polymerase chain reaction (PCR) using specific primer pairs of OI1 and OI2c was conducted to assess the presence and to amplify the Candidatus Liberibacter asiaticus in infected plants. The samples were then examined under transmission electron microscope for the determination and identification of Candidatus Liberibacter asiaticus. The spherical and rod shaped particles of this agent were found in phloem cells. The length of the bacteria ranged from 594.57 to 1368.16 nm (mean 930.09 nm) and its width ranged from 201.68 to 811.15 nm (mean 410.61nm). Cell wall membranes were irregular in shape and were of different thickness. Damage was caused by Candidatus Liberibacter asiaticus penetrating through the cell wall and their movement between cells. This study was conducted to confirm the presence of Candidatus Liberibacter asiaticus pathogen in citrus plant using transmission electron microscopy (TEM) and to identify the cell wall modifications of the phloem.

 

Key words: Citrus greening disease, huanglongbing, transmission electron microscope.

Abbreviation

HLB, Huanglongbing; TEM, transmission electron microscopy;PCR, polymerase chain reaction;  CTAB, cetyl trimethyl ammonium bromide; SC,sodium cacodylate.