phylogenetic positions of phytoplasmas associated with dieback, yellow crinkle and mosaic diseases of papaya, and their proposed inclusion in 'candidatus phytoplasma australiense' and a new taxon, 'candidatus phytoplasma australasia'.dna extracted from three papaya (carica papaya l.) plants, individually affected by dieback, yellow crinkle or mosaic diseases, was subjected to pcr using phytoplasma-specific primers to amplify the 16s rrna gene plus 16s-23s rrna intergenic spacer region. near-complete dna sequences obtained for the three pcr amplimers were subjected to phylogenetic analyses and direct sequence comparison with other phytoplasma 16s rdna and 16s-23s spacer region dna sequences. the papaya yellow crinkle (ppyc) a ...19989734050
molecular identification of a new phytoplasma associated with alfalfa witches'-broom in oman.abstract alfalfa (medicago sativa) plants showing witches'-broom symptoms typical of phytoplasmas were observed from al-batinah, al-sharqiya, al-bureimi, and interior regions of the sultanate of oman. phytoplasmas were detected from all symptomatic samples by the specific amplification of their 16s-23s rrna gene. polymerase chain reaction (pcr), utilizing phytoplasma-specific universal primer pairs, consistently amplified a product of expected lengths when dna extract from symptomatic samples wa ...200218944213
identification of genes in the tomato big bud phytoplasma and comparison to those in sweet potato little leaf-v4 phytoplasma.genetic relatedness of phytoplasmas is commonly defined on the basis of differences in the highly conserved 16s rrna gene, which may not resolve closely related phytoplasmas. an example of this is the closely related tomato big bud (tbb) and sweet potato little leaf strain v4 (spll-v4) phytoplasmas, which cannot easily be differentiated by their 16s rrna gene sequences. this study aimed to identify genes on the tbb phytoplasma chromosome which could be used to examine genetic variation between t ...200312855731
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