First Detection of Phytoplasmas in Rhododendron in the Czech Republic

A 10-year-old plant of rhododendron ('Cunningham's White' PS986) with leaf malformation and variegation was observed in Prague in 1997. This plant was micropropagated, and regenerants with severe, mild and no symptoms were obtained. Phytoplasma infection was detected using nested polymerase chain reaction (PCR) in the original PS986 plant and the symptomatic regenerants but not in nonsymptomatic plants. During 2002, phytoplasmas were also detected in rhododendron hybrids, PS2716 and PS2439, grown in Pruhonice that showed similar symptoms as the plant observed in Prague. In nested PCR, performed as described previously (1), primer pairs R16F1/R16R0 and R16F2/R16R2 were used. The phytoplasmas detected were classified by restriction fragment length polymorphism analysis using R16F2/R16R2 PCR fragments. Following digestion with restriction endonuclease MseI (Promega, Madison, WI), the restriction profiles obtained were identical with the pattern of the stolbur phytoplasma group (16SrXII group) as determined previously (2). To our knowledge, this is the first finding of stolbur-type phytoplasma in rhododendron worldwide. References: (1) R. Fialova et al. Plant Prot. Sci. 39(1):7, 2003. (2) I.-M Lee et al. Int. J. Syst. Bacteriol. 48:1153,1998.