Expression of phytoplasma-induced witches' broom disease symptoms in acid lime (Citrus aurantifolia) trees is affected by climatic conditions

A. G. Al-Ghaithi, A. M. Al-Sadi, M. S. Al-Hammadi, R. M. Al-Shariqi, R. A. Al-Yahyai, I. H. Al-Mahmooli, C. M. Carvalho, S. L. Elliot, S. A. Hogenhout

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Witches' broom disease (WBD), caused by 'Candidatus Phytoplasma aurantifolia', is a serious disease of acid lime (Citrus aurantifolia) in Oman and the UAE. However, little is known about the distribution of phytoplasma and the expression of WBD symptoms in different geographical locations. A survey was carried out in 18 districts in Oman and the UAE covering 143 orchards and 5823 acid lime trees. 'Candidatus Phytoplasma aurantifolia' was detected in acid lime in all the 18 surveyed districts. However, the development of typical symptoms of WBD was only observed in 12 districts. Districts in which the phytoplasma was present but symptoms were not expressed were located either in desert areas or in areas characterized by semitropical conditions. Phylogenetic analysis of 16 phytoplasma isolates from trees developing WBD symptoms and six phytoplasma isolates from trees with no WBD symptoms showed that all isolates share an identical 16S rRNA sequence, belonging to subgroup II-B. Quantitative PCR analysis showed that the concentration of phytoplasma is significantly higher (8800-801 000 copies) in leaves developing WBD symptoms compared to 2-268 copies in symptomless leaves from the same trees and 8-874 copies in acid lime trees from areas where disease symptoms were not expressed. The lack of expression of WBD symptoms under certain environmental conditions may suggest that symptom development and phytoplasma are affected by certain unfavourable environmental conditions. These findings could provide a basis for managing WBD through encouraging lime cultivation under climatic conditions less conducive to WBD symptom expression.

Original languageEnglish
JournalPlant Pathology
DOIs
Publication statusAccepted/In press - 2017

Fingerprint

Phytoplasma
Citrus aurantiifolia
witches' broom
Citrus
signs and symptoms (plants)
Acids
acids
Oman
lime
environmental factors
Geographical Locations
leaves
deserts
quantitative polymerase chain reaction
orchards

Keywords

  • 16SrII-B
  • Phytoplasma titre
  • qPCR
  • Witches' broom disease of lime

ASJC Scopus subject areas

  • Agronomy and Crop Science
  • Genetics
  • Plant Science
  • Horticulture

Cite this

Expression of phytoplasma-induced witches' broom disease symptoms in acid lime (Citrus aurantifolia) trees is affected by climatic conditions. / Al-Ghaithi, A. G.; Al-Sadi, A. M.; Al-Hammadi, M. S.; Al-Shariqi, R. M.; Al-Yahyai, R. A.; Al-Mahmooli, I. H.; Carvalho, C. M.; Elliot, S. L.; Hogenhout, S. A.

In: Plant Pathology, 2017.

Research output: Contribution to journalArticle

Al-Ghaithi, A. G. ; Al-Sadi, A. M. ; Al-Hammadi, M. S. ; Al-Shariqi, R. M. ; Al-Yahyai, R. A. ; Al-Mahmooli, I. H. ; Carvalho, C. M. ; Elliot, S. L. ; Hogenhout, S. A. / Expression of phytoplasma-induced witches' broom disease symptoms in acid lime (Citrus aurantifolia) trees is affected by climatic conditions. In: Plant Pathology. 2017.
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abstract = "Witches' broom disease (WBD), caused by 'Candidatus Phytoplasma aurantifolia', is a serious disease of acid lime (Citrus aurantifolia) in Oman and the UAE. However, little is known about the distribution of phytoplasma and the expression of WBD symptoms in different geographical locations. A survey was carried out in 18 districts in Oman and the UAE covering 143 orchards and 5823 acid lime trees. 'Candidatus Phytoplasma aurantifolia' was detected in acid lime in all the 18 surveyed districts. However, the development of typical symptoms of WBD was only observed in 12 districts. Districts in which the phytoplasma was present but symptoms were not expressed were located either in desert areas or in areas characterized by semitropical conditions. Phylogenetic analysis of 16 phytoplasma isolates from trees developing WBD symptoms and six phytoplasma isolates from trees with no WBD symptoms showed that all isolates share an identical 16S rRNA sequence, belonging to subgroup II-B. Quantitative PCR analysis showed that the concentration of phytoplasma is significantly higher (8800-801 000 copies) in leaves developing WBD symptoms compared to 2-268 copies in symptomless leaves from the same trees and 8-874 copies in acid lime trees from areas where disease symptoms were not expressed. The lack of expression of WBD symptoms under certain environmental conditions may suggest that symptom development and phytoplasma are affected by certain unfavourable environmental conditions. These findings could provide a basis for managing WBD through encouraging lime cultivation under climatic conditions less conducive to WBD symptom expression.",
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T1 - Expression of phytoplasma-induced witches' broom disease symptoms in acid lime (Citrus aurantifolia) trees is affected by climatic conditions

AU - Al-Ghaithi, A. G.

AU - Al-Sadi, A. M.

AU - Al-Hammadi, M. S.

AU - Al-Shariqi, R. M.

AU - Al-Yahyai, R. A.

AU - Al-Mahmooli, I. H.

AU - Carvalho, C. M.

AU - Elliot, S. L.

AU - Hogenhout, S. A.

PY - 2017

Y1 - 2017

N2 - Witches' broom disease (WBD), caused by 'Candidatus Phytoplasma aurantifolia', is a serious disease of acid lime (Citrus aurantifolia) in Oman and the UAE. However, little is known about the distribution of phytoplasma and the expression of WBD symptoms in different geographical locations. A survey was carried out in 18 districts in Oman and the UAE covering 143 orchards and 5823 acid lime trees. 'Candidatus Phytoplasma aurantifolia' was detected in acid lime in all the 18 surveyed districts. However, the development of typical symptoms of WBD was only observed in 12 districts. Districts in which the phytoplasma was present but symptoms were not expressed were located either in desert areas or in areas characterized by semitropical conditions. Phylogenetic analysis of 16 phytoplasma isolates from trees developing WBD symptoms and six phytoplasma isolates from trees with no WBD symptoms showed that all isolates share an identical 16S rRNA sequence, belonging to subgroup II-B. Quantitative PCR analysis showed that the concentration of phytoplasma is significantly higher (8800-801 000 copies) in leaves developing WBD symptoms compared to 2-268 copies in symptomless leaves from the same trees and 8-874 copies in acid lime trees from areas where disease symptoms were not expressed. The lack of expression of WBD symptoms under certain environmental conditions may suggest that symptom development and phytoplasma are affected by certain unfavourable environmental conditions. These findings could provide a basis for managing WBD through encouraging lime cultivation under climatic conditions less conducive to WBD symptom expression.

AB - Witches' broom disease (WBD), caused by 'Candidatus Phytoplasma aurantifolia', is a serious disease of acid lime (Citrus aurantifolia) in Oman and the UAE. However, little is known about the distribution of phytoplasma and the expression of WBD symptoms in different geographical locations. A survey was carried out in 18 districts in Oman and the UAE covering 143 orchards and 5823 acid lime trees. 'Candidatus Phytoplasma aurantifolia' was detected in acid lime in all the 18 surveyed districts. However, the development of typical symptoms of WBD was only observed in 12 districts. Districts in which the phytoplasma was present but symptoms were not expressed were located either in desert areas or in areas characterized by semitropical conditions. Phylogenetic analysis of 16 phytoplasma isolates from trees developing WBD symptoms and six phytoplasma isolates from trees with no WBD symptoms showed that all isolates share an identical 16S rRNA sequence, belonging to subgroup II-B. Quantitative PCR analysis showed that the concentration of phytoplasma is significantly higher (8800-801 000 copies) in leaves developing WBD symptoms compared to 2-268 copies in symptomless leaves from the same trees and 8-874 copies in acid lime trees from areas where disease symptoms were not expressed. The lack of expression of WBD symptoms under certain environmental conditions may suggest that symptom development and phytoplasma are affected by certain unfavourable environmental conditions. These findings could provide a basis for managing WBD through encouraging lime cultivation under climatic conditions less conducive to WBD symptom expression.

KW - 16SrII-B

KW - Phytoplasma titre

KW - qPCR

KW - Witches' broom disease of lime

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