Keywords Rice . Orange leaf phytoplasma . Nested PCR
Phytoplasmas are intracellular obligate prokaryotes that lack cell
walls and have very small genomes (680–1,600 kb). Since the
first report by Doi et al. (1967), phytoplasmas have been
identified as pathogens in different plant genera and in some
cases have caused severe epidemics in major crops such as
grapevine, sugarcane and coconut (Weintraub and Beanland
2006). Phytoplasmas cause complex syndromes with symptoms
such as stunting, proliferating auxiliary shoots, forming sterile
deformed flowers, virescence, and phyllody in several hundred
plant species (Lee et al. 2000). Based on phylogenetic analysis of
gene sequences (16S rRNA) phytoplasmas were recently
assigned to a provisional genus, ‘Candidatus (Ca.)
Phytoplasma’ within the class Mollicutes (IRPCM 2004). The
aster yellows (AY) phytoplasma group (16SrI) comprises AY
and numerous related phytoplasmas that are associated with
more than 100 economically important diseases worldwide,
representing the most diverse phytoplasma group (Lee et al.
2004)