Phytoplasma was identified from leaf lettuce (Lactuca sativa) cultivated in commercial green-house in Korea. Diseased leaf lettuce revealed proliferation of shoots, and yellowing and shrinking of leaves (lettuce proliferation-K). Polymerase chain reaction (PCR) with universal primer pair P1/P6, and aster yellows (AY) specific primer pair R16F1/R1 amplified 1.5kb and 1.1kb length of DNA fragments, respectively. Nucleotide sequences of 16S rRNA gene were determined (Gen Bank accession no EF489024). Phylogenetic analysis of 16S rDNA showed the closest relationship with AY phytoplasma (GenBank accession no. AY389822 and AY389826), indicating that lettuce proliferation-K is a member of AY. Phytoplasma bodies were detected in phloem sieve tubes of diseased lettuce by transmission electron microscopy. The structures had round or pleomorphic shapes with a diameter of 130-300nm. Phylogenetic analysis of 16S rRNA gene, microscopic observation of phytoplasma bodies and symptomatology indicated that lettuce proliferation-K is caused by phytoplasma in the AY group. This is the first report of phytoplasma disease in lettuce in Korea.
[1]
L. Madden,et al.
Temporal Distribution of Aster Leafhopper Sex Ratios and Spatial Pattern of Aster Yellows Phytoplasma Disease in Lettuce
,
2005
.
[2]
S. Miller,et al.
Molecular and symptom analyses of phytoplasma strains from lettuce reveal a diverse population.
,
2004,
Phytopathology.
[3]
I. M. D. Vries.
Origin and domestication of Lactuca sativa L.
,
1997,
Genetic Resources and Crop Evolution.
[4]
C. Hiruki,et al.
Amplification of 16S rRNA genes from culturable and nonculturable mollicutes
,
1991
.
[5]
P. Weintraub,et al.
Insect vectors of phytoplasmas.
,
2006,
Annual review of entomology.
[6]
R. Hammond,et al.
Use of mycoplasmalike organism (MLO) group-specific oligonucleotide primers for nested-PCR assays to detect mixed-MLO infections in a single host plant.
,
1994
.
[7]
R. Davis,et al.
Phloem-limited prokaryotes in sieve elements isolated by enzyme treatment of diseased plant tissues
,
1983
.