'Candidatus phytoplasma phoenicium' sp. nov., a novel phytoplasma associated with an emerging lethal disease of almond trees in Lebanon and Iran.
Almonds (Prunus amygdalus) represent an important crop in most Mediterranean countries. A new and devastating disease of almond trees in Lebanon was recently reported, characterized by the development of severe witches'-brooms on which no flowers or fruits developed, and leading to tree death within a few years. A phytoplasma was detected in diseased trees by PCR amplification of rRNA operon sequences, and RFLP patterns of amplified DNA indicated that the phytoplasma belonged to the pigeon pea witches'-broom (PPWB) group. In the present work, the presence of a phytoplasma in symptomatic plants was confirmed by electron microscopy; this phytoplasma was graft-transmissible to almond, plum and peach seedlings. The phytoplasma was characterized by sequence analysis of rRNA genes and was shown to be different from the phytoplasmas previously described in the PPWB group. A 16S rDNA phylogenetic tree identified the almond tree phytoplasma as a member of a distinct subclade of the class Mollicutes. Oligonucleotides have been defined for specific detection of the new phytoplasma. The almond phytoplasma from Lebanon was shown to be identical to a phytoplasma that induces a disease called 'almond brooming' in Iran, but different from another PPWB-group phytoplasma that infects herbaceous annual plants in Lebanon. Based on its unique properties, the name 'Candidatus Phytoplasma phoenicium' is proposed for the phytoplasma associated with almond witches'-broom in Lebanon and Iran.
Verdin
Eric
E
UMR GDPP, Institut National de la Recherche Agronomique BP 81, 33883 Villenave d'Ornon cedex, France.
Salar
Pascal
P
UMR GDPP, Institut National de la Recherche Agronomique BP 81, 33883 Villenave d'Ornon cedex, France.
Danet
Jean-Luc
JL
UMR GDPP, Institut National de la Recherche Agronomique BP 81, 33883 Villenave d'Ornon cedex, France.
Choueiri
Elia
E
Lebanese Agricultural Research Institute, Tal Amara, Rayak, Zahle, PO Box 287, Lebanon.
Jreijiri
Fouad
F
Lebanese Agricultural Research Institute, Tal Amara, Rayak, Zahle, PO Box 287, Lebanon.
El Zammar
Souheir
S
Lebanese Agricultural Research Institute, Tal Amara, Rayak, Zahle, PO Box 287, Lebanon.
Gélie
Brigitte
B
UMR GDPP, Institut National de la Recherche Agronomique BP 81, 33883 Villenave d'Ornon cedex, France.
Bové
Joseph M
JM
UMR GDPP, Institut National de la Recherche Agronomique BP 81, 33883 Villenave d'Ornon cedex, France.
Garnier
Monique
M
UMR GDPP, Institut National de la Recherche Agronomique BP 81, 33883 Villenave d'Ornon cedex, France.
D000129:Acholeplasmataceae / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D004269:DNA, Bacterial / Q000032:analysis; D004275:DNA, Ribosomal / Q000032:analysis; D007492:Iran; D007861:Lebanon; D018545:Lactuca / Q000382:microbiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D010935:Plant Diseases / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D027861:Prunus / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012338:RNA, Ribosomal, 23S / Q000235:genetics; D017422:Sequence Analysis, DNA; D031053:Vinca / Q000382:microbiology
D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D012338:RNA, Ribosomal, 23S