The agent associated with blue dwarf disease in wheat represents a new phytoplasma taxon, ‘Candidatus Phytoplasma tritici’

Abstract

Wheat blue dwarf (WBD) is one of the most economically damaging cereal crop diseases in northwestern PR China. The agent associated with the WBD disease is a phytoplasma affiliated with the aster yellows (AY) group, subgroup C (16SrI-C). Since phytoplasma strains within the AY group are ecologically and genetically diverse, it has been conceived that the AY phytoplasma group may consist of more than one species. This communication presents evidence to demonstrate that, while each of the two 16 rRNA genes of the WBD phytoplasma shares >97.5 % sequence similarity with that of the ‘Candidatus Phytoplasma asteris’ reference strain, the WBD phytoplasma clearly represents an ecologically separated lineage: the WBD phytoplasma not only has its unique transmitting vector (Psammotettix striatus) but also elicits a distinctive symptom in its predominant plant host (wheat). In addition, the WBD phytoplasma possesses molecular characteristics that further manifest its significant divergence from ‘Ca. P. asteris’. Such molecular characteristics include lineage-specific antigenic membrane proteins and a lower than 95 % genome-wide average nucleotide identity score with ‘Ca. P. asteris’. These ecological, molecular and genomic evidences justify the recognition of the WBD phytoplasma as a novel taxon, ‘Candidatus Phytoplasma tritici’.

Comparative Genome Analysis of ‘Candidatus Phytoplasma luffae’ Reveals the Influential Roles of Potential Mobile Units in Phytoplasma Evolution

“…More importantly, with the increased availability of genome sequences from diverse phytoplasmas (Table 1), we performed genus-level comparative analysis to obtain a more comprehensive picture of their genomic diversity. This improves upon previous works that are limited to comparisons of closely related taxa or have sparse sampling (Bai et al, 2006;Tran-Nguyen et al, 2008;Kube et al, 2012;Saccardo et al, 2012;Andersen et al, 2013;Chung et al, 2013;Orlovskis et al, 2017;Wang et al, 2018a;Cho et al, 2019Cho et al, , 2020aSeruga Music et al, 2019;Kirdat et al, 2021;Zhao et al, 2021). Furthermore, our focused analysis of the potential mobile units (PMUs) (Bai et al, 2006) revealed the influential roles of these mobile genetic elements in the evolution of phytoplasma genome organization and effector gene content.…”

Comparative Genome Analysis of ‘Candidatus Phytoplasma luffae’ Reveals the Influential Roles of Potential Mobile Units in Phytoplasma Evolution

“…More importantly, with the increased availability of genome sequences from diverse phytoplasmas (Table 1), we performed genus-level comparative analysis to obtain a more comprehensive picture of their genomic diversity. This improves upon previous works that are limited to comparisons of closely related taxa or have sparse sampling (Bai et al, 2006;Tran-Nguyen et al, 2008;Kube et al, 2012;Saccardo et al, 2012;Andersen et al, 2013;Chung et al, 2013;Orlovskis et al, 2017;Wang et al, 2018a;Cho et al, 2019Cho et al, , 2020aSeruga Music et al, 2019;Kirdat et al, 2021;Zhao et al, 2021). Furthermore, our focused analysis of the potential mobile units (PMUs) (Bai et al, 2006) revealed the influential roles of these mobile genetic elements in the evolution of phytoplasma genome organization and effector gene content.…”

Screening potential insect vectors in a museum biorepository reveals undiscovered diversity of plant pathogens in natural areas

“…Phytoplasma" species have been described (IRPCM, 2004;Kirdat et al, 2020;Naderali et al, 2017;Rodrigues Jardim et al, 2020;Šafářová et al, 2016;Zhao et al, 2021). Nevertheless, the phytoplasma lineage is a highly diverse monophyletic group (Gupta et al, 2018;Zhao et al, 2015), having been classified into 36 groups, and more than 150 subgroups based on distinct 16S rRNA gene restriction fragment length polymorphism patterns and sequencing (Lee et al, 1998;Naderali et al, 2017;Rodrigues Jardim et al, 2020;Seemüller et al, 1998;Wei et al, 2007;Zhao et al, 2009).…”