First report of 'Candidatus Phytoplasma trifolii' associated with leaf reddening and upright growth in pears (Pyrus communis L.)

Abstract

The natural occurrence of 'Candidatus Phytoplasma trifolii' in pear trees (Pyrus communis Linnaeus) is reported here for the first time. In 2017, a total of thirty-five pear trees, two of them exhibiting leaf rolling along the midvein, reddening, bushy appearance, and upright growth symptoms were sampled in different locations in Van province, Turkey. The total deoxyribonucleic acid was extracted from symptomatic and asymptomatic plants. The purified DNA served as a template in nested polymerase chain reaction (nested-PCR) assays, performed to amplify 16S rRNA sequences using universal primer pairs (R16mF2/R16mR1 and R16F2n/R16R2). The resulting PCR products were then cloned into a pGEM T-Easy vector and sequenced bidirectionally. The phytoplasma strain, group, and subgroup identity were determined using the in silico restriction fragment length polymorphism (RFLP) analysis of the 16S ribosomal RNA-encoding gene sequences profiling with seventeen distinct restriction enzymes. Of the thirty-five pear samples, only two yielded 1 256 bp and 1 258 bp DNA fragments and were designated as Van-Pr3 (Acc. No. MH709141) and Van-Pr4 (Acc. No. MH730561), respectively. Based on the in silico virtual RFLP pattern analysis of the 16S rRNA sequences, we confirmed the presence of 'Ca. P. trifolii' belonging to the clover proliferation group and both identified phytoplasmas were identical with the similarity coefficient of 1.00 to the reference pattern of 16Sr group VI, subgroup A (Acc. No. AY390261). Here we report that the pear tree is an alternate host of the 'Ca. P. trifolii'.

Türkiye’nin Iğdır İli’nde sararma ve çalımsı görünüm gösteren biber bitkilerinde ‘Candidatus phytoplasma trifolii’nin varlığı

“…Apart from pepper, the phytopathogen 'Ca. P. trifolii' is also infectious to other solanaceous, cucurbits, leguminous, and graminae, fruit trees, weeds, some insects, ornamental plants, and weeds (Alp et al, 2016;Usta et al, 2017;Girsova et al, 2017;Salas-Muñoz et al, 2018;Oksal et al, 2017Oksal et al, , 2020Güller, 2021;Usta et al, 2021Usta et al, , 2022.…”

“…Especially in some cultivated plants, yield loss reaches 40% in eggplant, 60% in tomato, 30-80% in potato and 80% in cucumber (Bogoutdinov et al, 2008;Navratil et al, 2009;Rao & Kumar, 2017). In Turkey, various phytoplasma groups were detected in cultivated crops and ornamental plants (Alp et al, 2016;Usta et al, 2017), in orchards (Sertkaya et al, 2008;Usta et al, 2021), in maize from field crops (Güller, 2021), and grapevine (Ertunc et al, 2015). Infections of the phytoplasma-infected plants were typically recognized using 16S rRNA gene segment by molecular tools, including PCR, restriction fragment evaluation, and sequencing Hodgetts et al, 2007).…”

Investigation on phytoplasma diseases, their potential insect vectors and other hosts in pepper (Capsicum annuum L.) growing areas of Hatay-Turkey

“…Ca. Phytoplasma trifolii was first reported to be the organism that caused the formation of clover proliferation (CP) in flowers of the alsike clover (Trifolium hybridum) plants in Canada in the early 1960s (Chiykowski, 1965); today it has been isolated from many vegetables, fruit trees and weeds (Usta et al, 2018;Zamharir, 2018;Oksal, 2020;Usta et al, 2021). In Turkey, Ca.…”