Abstract:
Bermuda grass, Cynodon dactlylon (L.), is a grass of the family Poaceae.
Bermuda grass white leaf (BGWL) caused by a phytoplasma belonging to
the 16SrXIV group, has been reported from many countries including Asia.
C. dactylon plants were observed in Matara and Monaragala districts
showing symptoms similar to Bermuda grass white leaf disease caused by
BGWL phytoplasma. Affected grasses are exhibited whitening of leaves,
bushy growing habit, small leaves, shortened stolons/rhizomes, stunting,
proliferation of auxiliary shoots and death. Plants exhibiting typical BGWL
symptoms and apparently healthy (symptomless) plants were collected and
DNA was extracted from leaves using CTAB method. DNA was assayed in
a nested-PCR with phytoplasma universal rDNA primers P1/P7 and
R16R2/R16f2n to amplify the 16SrRNA gene of phytoplasma. DNA
extracted from all symptomatic plants produced PCR products of 1250bp
and were not produced in DNA from symptomless plants. The phytoplasma
16SrRNA region was sequenced directly with primers and compared by
BLAST analysis with those of other phytoplasma sequences in the Gene
Bank. The highest sequence homology (99%) obtained was that of
‘Candidatus Phytoplasma cynodontis’ belongs to the BGWL 16SrXIV. This
is the first molecular identification of ‘Candidatus Phytoplasma cynodontis’
(16SrXIV group) associated with Bermuda grass white leaf disease in Sri
Lanka
