Molecular Characterization of Phytoplasmas Associated with Potato Purple TopDisease in Iran

摘要

Potato plants with symptoms suggestive of potatopurple top disease (PPTD) occurred in the central,western and north-western regions of Iran. Polymerasechain reaction (PCR) and nested PCR assays wereperformed using phytoplasma universal primer pairP1/P7 followed by primer pairs R16F2n/R16R2 andfU5/rU3 for phytoplasma detection. Using primerpairs R16F2n/R16R2 and fU5/rU3 in nested PCR,the expected fragments were amplified from 53% ofsymptomatic potatoes. Restriction fragment lengthpolymorphism (RFLP) analysis using AluI, CfoI,EcoRI, KpnI, HindIII, MseI, RsaI and TaqI restrictionenzymes confirmed that different phytoplasmaisolates caused PPTD in several Iranian potato-growingareas. Sequences analysis of partial 16S rRNAgene amplified by nested PCR indicated that'Candidatus Phytoplasma solani', 'Ca. Phytoplasmaastris' and 'Ca. Phytoplasma trifolii' are prevalent inpotato plants showing PPTD symptoms in the productionareas of central, western and north-westernregions of Iran, although 'Ca. Phytoplasma solani' ismore prevalent than other phytoplasmas. This is thefirst report of phytoplasmas related to 'Ca. Phytoplasmaastris', 'Ca. Phytoplasma solani' and 'Ca. Phytoplasmatrifolii' causing PPTD in Iran.