‘Candidatus Phytoplasma malaysianum’, a novel taxon associated with virescence and phyllody of Madagascar periwinkle (Catharanthus roseus)

Abstract

This study addressed the taxonomic position and group classification of a phytoplasma responsible for virescence and phyllody symptoms in naturally diseased Madagascar periwinkle plants in western Malaysia. Unique regions in the 16S rRNA gene from the Malaysian periwinkle virescence (MaPV) phytoplasma distinguished the phytoplasma from all previously described 'Candidatus Phytoplasma' species. Pairwise sequence similarity scores, calculated through alignment of full-length 16S rRNA gene sequences, revealed that the MaPV phytoplasma 16S rRNA gene shared 96.5 % or less sequence similarity with that of previously described 'Ca. Phytoplasma' species, justifying the recognition of the MaPV phytoplasma as a reference strain of a novel taxon, 'Candidatus Phytoplasma malaysianum'. The 16S rRNA gene F2nR2 fragment from the MaPV phytoplasma exhibited a distinct restriction fragment length polymorphism (RFLP) profile and the pattern similarity coefficient values were lower than 0.85 with representative phytoplasmas classified in any of the 31 previously delineated 16Sr groups; therefore, the MaPV phytoplasma was designated a member of a new 16Sr group, 16SrXXXII. Phytoplasmas affiliated with this novel taxon and the new group included diverse strains infecting periwinkle, coconut palm and oil palm in Malaysia. Three phytoplasmas were characterized as representatives of three distinct subgroups, 16SrXXXII-A, 16SrXXXII-B and 16SrXXXII-C, respectively.

The underestimated diversity of phytoplasmas in Latin America

“…So far, 32 16Sr groups have been formally described, which are generally associated with the description of novel candidate species of 'Ca. Phytoplasma' Lee et al, 2011;Nejat et al, 2013). In this study, two novel 16Sr groups were identified from previous reports.…”

“…In 1993, the first 16S rRNA RFLP (16Sr) group was delineated (Lee et al, 1993) and, in 2009, Zhao and colleagues reported the existence of 29 16Sr groups designated 16SrI-16SrXXIX . Recently, this has been expanded to include groups up to 16SrXXXII (Nejat et al, 2013), highlighting the vast diversity among phytoplasmas strains worldwide. The development and validation of computer-simulated RFLP analysis, along with an automated RFLP patterncomparison program that facilitates the calculation of similarity coefficients for differentiating phytoplasma groups/ subgroups, was an important advancement in the field of phytoplasma characterization (Wei et al, 2007(Wei et al, , 2008b.…”

“…To date, 37 candidate species of 'Ca. Phytoplasma' have been formally described, and more than ten potentially novel species have been suggested based on the similarity of 16S rRNA-encoding gene sequences (IRPCM, 2004;Nejat et al, 2013;Harrison et al, 2014). Phylogenetic analysis of 16S rRNA-encoding gene sequences from reference strains of candidate species of 'Ca.…”

Especies Arbóreas de las Familias Euphorbiaceae, Pittosporaceae y Salicaceae son Infectadas por ‘CA. Phytoplasma fraxini’ y ‘CA. Phytoplasma asteris’ en Infecciones Mixtas en Bogotá, Colombia

“…En la actualidad existen dos sistemas paralelos de clasificación, ambos basados en el gen 16SrDNA. El primero establece los grupos a partir de patrones de corte de 17 enzimas de restricción en 32 grupos 16Sr RNA (Nejat et al, 2013). A su vez, cada grupo puede estar subdividido en subgrupos cuya determinación se complementa usando secuencias de otros genes como rp (proteínas ribosomales), secY, tuf y la región intergénica espaciadora 16S-23SrDNA, entre otros (Smart et al, 1996;Martini et al, 2007;.…”

Identification of a novel subgroup 16SrII-U phytoplasma associated with papaya little leaf disease

“…Phytoplasma' species have been formally described based on 16S rRNA gene sequence phylogeny and/or biological/phytopathological characteristics (Firrao et al, 2004;Harrison et al, 2014). Based on their identification and classification by RFLP analysis of 16S rRNA gene sequences, 32 phytoplasma/16Sr groups and more than 100 subgroups have been identified (Lee et al, 1993(Lee et al, , 1998Nejat et al, 2013).…”