The most efficient method to control the plant virus diseases is breeding resistant cultivars. However, the resistance could be broken down after using resistant cultivars. This study was aimed to determine the prevalence and also serological and molecular characterization of Tomato spotted wilt virus (TSWV) and Cucumber mosaic virus (CMV) that cause infections, especially, in resistant pepper cultivars. For this reason, samples were collected from pepper growing greenhouses and open fields during vegetation period of 2015 in different parts of Antalya province including Kumluca, Demre, Serik and Aksu districts. Out of 148 pepper samples collected, 53 (35.81%) were infected with TSWV and 11 (7.34%) with CMV as a result of Double-Antibody Sandwich Enzyme-Linked Immunosorbent Assay (DAS-ELISA) test. Some regions on S RNA (nucleocapsid protein gene), M RNA (glycoprotein gene) and L RNA (RNAdependent RNA polymerase gene) of TSWV genome; RNA 1 (helicase/methyltransferase gene) and RNA 3 (coat protein gene) of CMV genome of DAS-ELISA positive samples were amplified by RT-PCR with specific primers. Nucleotide similarity rates of nucleocapsid protein gene, glycoprotein gene and RNA-dependent RNA polymerase gene regions of TSWV isolate varied between 92-98% identity with other isolates in GenBank and CMV isolate varied between 89-96%. TSWV isolate showed nucleotide identity varied between 92-97% with Tsw resistance breaking isolates from Capsicum plants in Turkey, Italy and Spain. Genetic determinant for overcoming pepper Tsw resistance is located in S segment but aminoacid substitutions responsible for TSWV breakdown remain contradictory in several reports.

Antalya ili Demre ilçesi biber yetiştiriciliğinde Tomato spotted wilt virus (TSWV) ve Cucumber mosaic virus (CMV) etmenlerinin yaygınlığının belirlenmesi* Determination and prevalence of Tomato spotted wilt virus (TSWV) and Cucumber mosaic virus (CMV) in pepper production areas in Demre district of Antalya * Bu makale ilk yazarın lisans tezinden özetlenmiştir.

Tomato spotted wilt virus (TSWV) is economically prominent disease for its impact on tobacco (Nicotiana tabacum L.) production worldwide. An increase of the incidence of symptoms typical of TSWV has been observed in tobacco production areas in Denizli province of Turkey where tobacco is significantly grown. Surveys were conducted to determine the prevalence status of TSWV in tobacco cultivars and its possible sources of infections in four tobacco growing districts of Denizli province. A total of 501 plant samples from field-grown tobaccos, weeds, potential intermediate hosts, seedlings and seeds were collected during 2019 and tested by DAS-ELISA. Of these plants, 243 belong to 55 different weed species from 26 different families with intermediate host potential. Throughout the study, 40 crop plant samples which could be intermediate hosts and 39 tobacco seed samples were also taken for testing. Adult thrips specimens were picked up from the fields and brought to the laboratory for preparations. Four vector virus species were detected when adult thrips individuals were diagnosed: Thrips tabaci Lindeman (Thysanoptera: Thripidae), Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), Aeolothrips intermedius Bagnall (Thysanoptera: Aeolothripidae) and Thrips major Uzel (Thysanoptera: Thripidae). Of the 179 tobaccos sampled, 31.2% was positive; besides, of 243 weeds tested 10 were found to be infected. Echinochloa crus-galli and Tordylium apulum were determined to be new host recordings for TSWV infection. Only one tomato plant from the crop plants as intermediate hosts was infected. Cucumber mosaic virus (CMV), Alfalfa mosaic virus (AMV) and Potato virus Y (PVY) was also confirmed in tobacco fields.

Objective: The objective of this study was to investigate tomato spotted wilt virus (TSWV) and cucumber mosaic virus (CMV) infections in tomato and pepper plants showing virus-induced symptoms in vegetable growing districts of İzmir, Turkey. Material and Methods: Surveys were carried out in tomato and pepper plantations in 2019 and 2021, and the incidences of these viruses in the collected leaf samples were determined by RT-PCR. Nucleotide identities and phylogenetic relationships of the TSWV and CMV isolates with other isolates retrieved from the GenBank database were determined. Results: The results of this study showed that tomato plants were infected at the same rate (21.50%) with TSWV and CMV. Out of the tested pepper samples, 64.15% were infected with TSWV and 25.47% with CMV. The results showed that, the identity rate of nucleoprotein region of TSWV isolates from tomato was 99-96% at nucleotide level while the isolates from pepper showed 100-95% identity. On the other hand, the capsid protein gene region of the tomato isolate of CMV had nucleotide identity rate of 98-95% with other isolates in GenBank, while that of its pepper isolates had 100-98% identity. Also, CMV isolates of this study showed close phylogenetic relationship with the CMV isolates of subgroup IB. Conclusion: This study revealed the prevalence of TSWV and CMV in symptomatic tomato and pepper samples in İzmir province and some molecular properties of them.

Viral agents that are obligate plant pathogens have different shapes and sizes and usually consist of nucleic acid and protein coat. They are different from other plant pathogens due to their unique structure. Viral genomes contain information necessary for replication of viruses and expression of their genes in plant. Many viral agents that cause disease in plants contain RNA as nucleic acid. Viral genome, which plays a direct role in the mechanism of disease in plants, plays an important role in evolutionary processes due to various external factors. It is known that genomes of viruses which cause problem on cultivated plants undergo genetic changes quite frequently. A variety of molecular biology techniques that are advancing day by day allow us to analyze and modify genomes on molecular level. Since genomes of plant viruses are small in size, they are suitable for researches on molecular level and great number of researches have been done in the last 50 years. Thus, it is possible to have better understanding of the organization of genomes. Understanding the genome structure of viruses offers an insight into their identification and development of control strategies.

Ribozom inaktive eden proteinler (RIP'ler) olarak adlandırılan bir grup protein, enzimatik yolla geri dönülmez bir şekilde ribozomlara zarar verme yeteneğindedir. RIP'ler Cucurbitaceae, Euphorbiaceae, Poaceae ve Caryophyllaceae gibi familyalara ait bazı bitki türlerinde yaygın olarak bulunmakla beraber bazı fungus ve deniz yosunlarında da saptanmıştır. RIP'ler genel olarak moleküler yapısına göre Tip1, Tip2 ve Tip3 olmak üzere 3 grupta toplanmaktadır. Doğadaki rolleri henüz tam olarak anlaşılmamış olmakla beraber, bazı özelliklerinin ortaya koyulması tarımsal uygulamalarda onlardan faydalanmak konusunda umut verici olmuştur. Bu proteinlerin bitkiler için patojenik olan bazı fungus ve virüslere karşı etkili olduğu çeşitli çalışmalarda rapor edilmiştir. Yapı, fonksiyon ve biyolojik aktiviteleri göz önüne alındığında bitkilerden izole edilen RIP'lerin gösterdikleri antiviral aktivitenin bitki virüs hastalıklarıyla mücadelede yeni gelişmeler açısından potansiyel taşıdığı görülmektedir.