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Characterisation and phylogeny of a phytoplasma inducing sandal spike disease in sandal ( Santalum album )
Author(s) -
Khan J.A.,
Singh S.K.,
Ahmad J.
Publication year - 2008
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.2008.00265.x
Subject(s) - phytoplasma , biology , aster yellows , santalum album , restriction fragment length polymorphism , broom , phylogenetic tree , mega , botany , restriction enzyme , nested polymerase chain reaction , polymerase chain reaction , genetics , dna , gene , ecology , physics , astronomy
Sandal ( Santalum album ) is an industrially important forest species in India, where it is devastated by sandal spike (SAS) disease. Diseased S. album trees show characteristic witches’ broom symptoms suspected to be caused by phytoplasma. Since the first report of occurrence of this disease at the end of 19th century, studies mainly have been carried out to detect SAS phytoplasma through various approaches. The causative agent, however, has remained poorly characterised at a molecular level. The present investigation was aimed to characterise the pathogen at this level. In nested PCR, a 1.4‐kb 16S rDNA fragment was amplified and analysed by restriction fragment length polymorphism using 17 restriction enzymes. The patterns were identical to those of strains AY1 and APh of the aster yellows subgroup 16SrI‐B, except for Bfa I, which gave a different pattern. After cloning and sequencing, a phylogenetic analysis revealed the closest relationship to aster yellows subgroup 16SrI‐B members. Nucleotide sequence identity ranged from 99.2% to 99.5% with this subgroup. On the basis of these results, the SAS phytoplasma was classified as a member of subgroup 16SrI‐B.