Association of a phytoplasma with a yellow leaf syndrome of sugarcane in Africa

Evidence is presented for the association of a phytoplasma, provisionally n amed sugarcane yellows phytoplasma (ScYP), in sugarcane affected by a yello w leaf syndrome. The phytoplasma was consistently detected in leaves of mor e than 40 varieties from eight African countries. It was present in all sym ptomatic as well as some asymptomatic field grown cane samples but not in p lants grown from true seed, and it was also observed in phloem sieve tubes by transmission electron microscopy. Phytoplasma 16S rDNA was confirmed by PCR, and restriction fragment analysis using RsaI and HaeIII confirmed that PCR-amplified products were of phytoplasma rather than of plant or of othe r pathogen origin. Sequences obtained from the intergenic spacer region, be tween the 16S and 23S rDNA genes, confirmed the identity of the phytoplasma as belonging to the western X group of phytoplasmas.