Detection and Molecular Characterization of two 'Candidatus Phytoplasma Trifolii' Isolates Infecting Peppers at the Same Ecological Niche


Oksal H. D., APAK F. K., Oksal E., Tursun N., Sipahioglu H. M.

INTERNATIONAL JOURNAL OF AGRICULTURE AND BIOLOGY, cilt.19, sa.6, ss.1372-1378, 2017 (SCI-Expanded) identifier identifier

Özet

Pepper (Capsicum annuum L.) cultivars exhibiting phytoplasma like symptoms including yellowing, flower sterility, necrosis, stunting and small leaves of lateral shoots were collected in Spring 2016 from Malatya province (Turkey). Leaf samples of the most common annual weeds and leafhoppers nearby symptomatic peppers were also sampled. Nested-PCR and virtual computer-simulated restriction fragment length polymorphism (virtual RFLP) methods have been implemented to ascertain and characterize the phytoplasma-associated disease. Using universal primer pairs in nested-PCR DNA fragments of approximately 1.2 kb were amplified from 3 pepper samples. None of the weed and leafhopper samples were reacted positive in PCR reactions. Next-generation sequencing (NGS) was used to sequence the amplified PCR fragments of two samples. The presence of 'Candidatus Phytoplasma trifolii' infections were confirmed by the analysis of 16S rDNA sequence and virtual-RFLP. Molecularly characterized isolates were designated as TR1 and TR2 (Acces. no: KY321932 and KY568694). Both isolates were identified as members of the clover proliferation phytoplasma group (subgroup 16SrVI-A) in pepper plants as strains of 'Ca. Phytoplasma trifolii'. Sequence alignment of the two 'Ca. Phytoplasma trifolii' isolates revealed a low level of genetic diversity. However, the restriction enzyme patterns of both isolates particularly in MseI profiles were differed from reference patterns of all previously established 'Ca. Phytoplasma trifolii' isolates in the world. Particularly, the TR2 isolate showed a point mutation comparing TR1 isolate and with reference strain (AY390261) of 'Ca. Phytoplasma trifolii'. This is the first report of 'Ca. Phytoplasma trifolii' isolates naturally infecting pepper plants from Turkey. (C) 2017 Friends Science Publishers