Living with Genome Instability: the Adaptation of Phytoplasmas to Diverse Environments of Their Insect and Plant Hosts

Abstract

Phytoplasmas ("CandidatusPhytoplasmaThe phylogenetic tree of mollicutes is composed of two major clades that diverged early in evolution (51). One clade contains the orders Acholeplasmatales and Anaeroplasmatales (AAA clade mollicutes), and the other clade contains the orders Mycoplasmatales and Entomoplasmatales (SEM clade mollicutes) (9). Phytoplasmas, formerly known as mycoplasma-like organisms of plants, form a monophyletic group in the order Acholeplasmatales (51) and were recently assigned to a novel genus, "Candidatus Phytoplasma" (41). Approximately 20 phytoplasma phylogenetic groups have been proposed based on 16S rRNA gene sequences, and new branches are continuously being discovered (69,85). Members of the order Acholeplasmatales are distinct from other mollicutes in several ways. For instance, whereas most mollicutes use UGA as a tryptophan codon instead of a stop codon, a feature they share with mitochondria, the acholeplasmas and phytoplasmas retained UGA as a stop codon (80).

Multilocus sequence analysis reveals the genetic diversity of European fruit tree phytoplasmas and supports the existence of inter-species recombination

“…The possibility that hypo-virulent isolates are impaired in carbon metabolism can be envisaged. Glycolysis is a pathway essential for phytoplasmas which have a reduced physiology as shown by the analysis of their small genome content (Bai et al, 2006;Oshima et al, 2004;Tran-Nguyen et al, 2008). This pathway is only partially present in 'Ca.…”

“…Until the publication of the 'Ca. P. mali' genome, the ability of phytoplasmas to perform recombination was questionable because they lack the genetic information to perform homologous recombination (Bai et al, 2006;Oshima et al, 2004). Nevertheless, it was discovered that 'Ca.…”

Detection of a novel intracellular microbiome hosted in arbuscular mycorrhizal fungi

“…The 16S rRNA gene was used as a target gene, but while in the CaGg genome the 16S rRNA gene is present in a single copy (Ghignone et al, 2012), in Mre one or at most two rRNA gene copies are expected based on the comparison with the closest microbes already sequenced (Fraser et al, 1995;Glass et al, 2000;Jaffe et al, 2004;Minion et al, 2004;Vasconcelos et al, 2005;Bai et al, 2006). The accuracy of qPCR primers of CaGg and Mre was confirmed by assessing the melting profile generated by each primer pair (Supplementary Figure S2).…”

Genetic diversity among phytoplasmas infecting Opuntia species: virtual RFLP analysis identifies new subgroups in the peanut witches'-broom phytoplasma group

“…It is well known that many phytoplasmas have two rRNA operons, rrnA and rrnB (Schneider & Seemüller, 1994;Lauer & Seemüller, 2000;Padovan et al, 2000;Davis & Dally, 2001;Jomantiene et al, 2002;Oshima et al, 2004;Bai et al, 2006). While the two rrn operons may be identical in some phytoplasma strains, apparent interoperon sequence heterogeneity exists in other strains (Lee et al, 1993;Firrao et al, 1996;Liefting et al, 1996;Davis & Sinclair, 1998;Jomantiene et al, 2002).…”