‘Candidatus Phytoplasma americanum’, a phytoplasma associated with a potato purple top wilt disease complex

Abstract

Potato purple top wilt (PPT) is a devastating disease that occurs in various regions of North America and Mexico. At least three distinct phytoplasma strains belonging to three different phytoplasma groups (16SrI, 16SrII and 16SrVI) have been associated with this disease. A new disease with symptoms similar to PPT was recently observed in Texas and Nebraska, USA. Two distinct phytoplasma strain clusters were identified. One belongs to the 16SrI phytoplasma group, subgroup A, and the other is a novel phytoplasma that is most closely related to, and shares 96?6 % 16S rRNA gene sequence similarity with, a member of group 16SrXII. Phylogenetic analysis of 16S rRNA gene sequences of the novel PPT-associated phytoplasma strains, previously described 'Candidatus Phytoplasma' organisms and other distinct unnamed phytoplasmas indicated that the novel phytoplasma, termed American potato purple top wilt (APPTW) phytoplasma, represents a distinct lineage and shares a common ancestor with stolbur phytoplasma, 'Candidatus Phytoplasma australiense', 'Candidatus Phytoplasma japonicum', 'Candidatus Phytoplasma fragariae', bindweed yellows phytoplasma (IBS), 'Candidatus Phytoplasma caricae' and 'Candidatus Phytoplasma graminis'. On the basis of unique 16S rRNA gene sequences and biological properties, it is proposed that the APPTW phytoplasma represents 'Candidatus Phytoplasma americanum', with APPTW12-NE as the reference strain.

The Second Skin: Ecological Role of Epibiotic Biofilms on Marine Organisms

“…Most of these studies are based on investigation of sponge – associated endosymbiotic microorganisms, while the information about microbes internally or externally associated with other animals is limited (but, see: Bodammer and Sawyer, 1981; Pukall et al, 2001; Harder et al, 2003; Kittelmann and Harder, 2005; Perez-Matos et al, 2007; Winters et al, 2010). It has been demonstrated that the community composition of epibiotic bacteria associated with the same sponge species from different locations remained consistent (Lee et al, 2006a, 2011), while microbial communities associated with different species of sponges differed substantially (Qian et al, 2006; Lee et al, 2011). This suggests a certain host-specificity of the biofilms (as it has been shown in algae) while in the vast majority of cases a mandatory restriction of a given bacterial strain to a particular host species has not yet been shown.…”

Phytoplasma Genomes: Evolution Through Mutually Complementary Mechanisms, Gene Loss and Horizontal Acquisition

“…Advantageously, the RFLP analysis-based scheme also distinguishes subtle pattern differences, making it possible to differentiate distinct subgroups within a phytoplasma group. Following inception of the scheme, 19 groups and more than 40 subgroups were delineated through conventional RFLP analysis (Lee et al 2006;Al-Saady et al 2008).…”

Ribosomal protein gene-based phylogeny for finer differentiation and classification of phytoplasmas

“…Comparative cladistic analyses were performed by using rplV-rpsC and 16S rRNA gene sequences from phytoplasma strains across 12 distinct phytoplasma 16Sr groups (Lee et al, 1998(Lee et al, , 2006b), other representative mollicutes and Grampositive walled bacteria. The analyses resulted in 32 equally parsimonious trees based on rp genes and 126 trees based on the 16S rRNA gene; representative trees were selected (Fig.…”