The phytoplasma associated with purple woodnettle witches'-broom disease in Taiwan represents a new subgroup of the aster yellows phytoplasma group

Abstract

In October 2013, a new disease affecting purple woodnettle, Oreocnide pedunculata, plants was found in Miaoli County, Taiwan. Diseased plants exhibited leaf yellowing and witches'-broom symptoms. Molecular diagnostic tools and electron microscopic cell observation were used to investigate the possible cause of the disease with a specific focus on phytoplasmas. The result of polymerase chain reaction with universal primer pairs indicated that phytoplasmas were strongly associated with the symptomatic purple woodnettles. The virtual restriction fragment length polymorphism (RFLP) patterns and phylogenetic analysis based on 16S rDNA and ribosomal protein, rplV-rpsC region revealed that purple woodnettle witches'-broom phytoplasma (PWWB) belongs to a new subgroup of 16SrI and rpI group and was designated as 16SrI-AH and rpI-Q, respectively, herein. RFLP analysis based on tuf gene region revealed that the PWWB belongs to tufI-B, but phylogenetic analysis suggested that PWWB should be delineated to a new subgroup under the tufI group. Taken together, our analyses based on 16S rRNA and rplV-rpsC region gave a finer differentiation while classifying the subgroup of aster yellows group phytoplasmas. To our knowledge, this is the first report of a Candidatus Phytoplasma asteris-related strain in 16SrI-AH, rpI-Q and tufI-B subgroup affecting purple woodnettle, and of an official documentation of purple woodnettle as being a new host of phytoplasmas.

Identification of Phytoplasmas Representing Multiple New Genetic Lineages from Phloem-Feeding Leafhoppers Highlights the Diversity of Phytoplasmas and Their Potential Vectors

“…( c ) This is re-designation of the subgroup 16SrI-AG reported by Santos-Cervantes et al [ 36 ] as the subgroup letter 16SrI-AG (MH279522) had already been assigned to NS1P1cB, BS, blueberry stunt, Canada. ( d ) This is re-designation of the subgroup 16SrI-H reported by Santos-Cervantes et al [ 36 ] as the subgroup letter 16SrI-H (KF923395) had already been published by Tseng et al [ 46 ].…”

“…Similarity coefficients derived from virtual RFLP analysis of 16S rRNA genes of strain PLH102-1 and other 16SrI subgroups were less than or equal to 0.97, the threshold for a new subgroup delineation [ 26 ]. Therefore, strain PLH102-1 was designated as a new subgroup 16SrI-AO ( Table 2 [ 10 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 ], some of previously reported 16SrI subgroups were reassigned due to duplication).…”

Campsisgrandiflora as a new host species harbouring two novel 16SrI subgroups of phytoplasmas

“…In addition, in the i Phyclassifier RFLP similarity coefficient table, CgWBP1 and 2 shared a similarity coefficient of 0.94, suggesting the two strains were distinguished from each other in subgroup. We, therefore, given the most recently named 16SrI subgroup was 16SrI‐AJ (Perez‐Lopez et al., 2019; Tseng et al., 2016), delineated the new 16SrI subgroups AK and AL.…”

“…The reason of the unspecific digestion was kept unknown. It is known that phytoplasmas of 16SrI are the main group occurred in China (Li, Zhang, Liu, et al, 2012), and various subgroups and novel subgroups were discovered (Li, Zhang, Liu, et al, 2012; Li et al., 2014; Luan et al., 2018; Tseng et al., 2016; Zhang et al., 2019). In this work, we extended the queue of 16SrI subgroups with another two novel subgroups of 16SrI‐AK and ‐AL.…”

“…So far, more than 30 16Sr groups (16SrI to XXXVI) have been established and described (Davis, Zhao, Wei, Dally, & Lee, 2017; Zhao & Davis, 2016). The 16SrI (aster yellows) group has more than 36 subgroups currently (Tseng et al., 2016), harbouring two species of “ Ca . P. asteris” and “ Ca .…”