First Report of a 16SrII-A Subgroup Phytoplasma Associated with Purple Coneflower (Echinacea purpurea) Witches'-Broom Disease in Taiwan

Abstract

A total of 18 petiole samples of symptomatic carrots were collected (13 samples in 2009 and 5 samples 2010). Five asymptomatic plants were also sampled. Three samples of psyllids (five individuals grouped) collected from one affected field in 2010 were also included in the assay. Total DNA was extracted with the DNeasy Plant Mini Kit (Qiagen, Valencia, CA), and analyzed by nested-PCR assays using primer pairs PI/P7 and R16F2n/R16R2n for phytoplasmas and ScR16Fl/ScR16Rl followed by ScR16FlA/ScR16R2 for 5. citri detection as described previously (3). PCR was performed using primer pairs OA2/O12c and CL514F/R to amplify a portion of 16S rDNA and rpU/rpIL ribosomal protein genes, respectively, for 'Ca. L. solanacearum' (4). 5. citri and phytoplasmas were not detected in any of the studied samples. However, a 1,168-bp 16S rDNA fragment and a 669-bp rplJIrplL fragment were amplified from DNA from 16 symptomatic carrot samples and three psyllid grouped samples using specific primers for 'Ca. L. solanacearum'. No DNA was amplified from the asymptomatic samples. These results indicate the presence of 'Ca. L. solanacearum' in the affected carrot and psyllid samples collected in Tenerife (Canary Islands). Four and one PCR products obtained from DNA of carrot and psyllid samples, respectively, with both primer pairs were sequenced. BLAST analysis of the 16S rDNA sequences obtained from infected carrots (GenBank Accession Nos. HQ454312, HQ4543I3, HQ454314, and HQ454315) and psyllids (HQ454316) showed 99% identity to those of 'Ca. L. solanacearum' amplified from carrot in Finland (GU373049) and B. cockerelU (EU812557). The rplJ/rpIL nucleotide sequences obtained from infected carrots (Accession Nos. HQ454317, HQ454318, HQ4543I9, and HQ454320) and psyllid (HQ454321) were 98% identical to the analogous rpUlrplL 'Ca. L. solanacearum' ribosomal protein gene from carrot (GU373051) in Finland and tomato (EU834I31) from New Zealand. To our knowledge, this is the first report of 'Ca. L. solanacearum' associated with psyllid-affected carrots in the Canary Islands (Tenerife, Spain) and also the first report of this plant pathogen associated with B. trigonica. References: (I) M. C. Cebrián et al. Plant Dis. 94:1264, 2010. (2) M. I. Font et al.

Detection and Inoculation of Peanut Witches' Broom Phytoplasma (16SrII‐A) and Periwinkle Leaf Yellowing Phytoplasma (16SrI‐B) in Citrus Cultivars in Taiwan

“…In the present investigation, the same was true that 89.7% (322/359) positive detections of HLB-Las occurred in examined citrus samples with HLB symptoms and a low detection (4/359) of phytoplasma was found. The citrus phytoplasma detected from a healthy-looking WP tree was identical in sequence alignment with the purple coneflower (Echinacea purpurea) witches' broom phytoplasma (Tseng et al 2012). The Taiwan citrus phytoplasma from a healthy WP tree was identified to be a PnWB phytoplasma (16SrII-A), the same as that found in grapefruit trees with HLB symptoms in Guangxi, China.…”

“…The citrus phytoplasma detected from a healthy‐looking WP tree was identical in sequence alignment with the purple coneflower ( Echinacea purpurea ) witches' broom phytoplasma (Tseng et al. ). The Taiwan citrus phytoplasma from a healthy WP tree was identified to be a PnWB phytoplasma (16SrII‐A), the same as that found in grapefruit trees with HLB symptoms in Guangxi, China.…”

“…The EPWB phytoplasma causing witches' broom on the purple coneflower was recently reported for the first time in Taiwan (Tseng et al. ). The TCS phytoplasma showed high identity (99.7%) of the 16S rDNA partial sequences with that of PnWB phytoplasma (), which revealed the infection into citrus plants of several cultivars, particularly in WP plants (Table ).…”

“…Through BLAST matches in GenBank database of NCBI, TCS phytoplasma shares 100% identity with that of Echinacea purpurea witches' broom (EPWB) phytoplasma (JN885461) and 99.7% identity with peanut witches' broom (PnWB) phytoplasma (JX403944) ( Table 3). The EPWB phytoplasma causing witches' broom on the purple coneflower was recently reported for the first time in Taiwan (Tseng et al 2012). The TCS phytoplasma showed high identity (99.7%) of the 16S rDNA partial sequences with that of PnWB phytoplasma (JX403944), which revealed the infection into citrus plants of several cultivars, particularly in WP plants (Table 2).…”

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

“…(Agrios, ; Davis et al , ). In Taiwan, phytoplasmas are responsible for numerous diseases including pear decline disease (in 16SrX and 16SrI groups), periwinkle leaf yellowing disease and paulownia witches'‐broom disease (in 16SrI group), peanut witches'‐broom disease, purple coneflower witches'‐broom disease and sweet potato witches'‐broom disease (in 16SrII group), rice yellow dwarf disease and sugarcane white leaf disease (in 16SrXI group), loofah witches'‐broom disease (in 16SrVIII group) and papaya dieback disease (in 16SrXII group) (Hung & Lin, ; Tseng et al , ). However, to date there is no report of a phytoplasma associated with purple woodnettle witches'‐broom (PWWB) disorder.…”