Molecular characterization of Verticillium dahliae kleb. isolates from greenhouse tomato production areas of the Elmalı district in Antalya

Verticillium wilt caused by soil-borne fungus Verticillium dahliae Kleb. results in serious quality, yield and economic losses in tomato fruit production in tomato growing areas of Antalya province. Due to the unavailability of an effective and economical chemical control method and ineffectivenes of the available cultural practices to manage the disease, the use of tomato varieties grafted onto resistant rootstocks have recently become highly common practice in tomato production in the province. Currently, tomato is mainly produced from grafted varieties in the highland greenhouse tomato growing areas of the Elmalı district of Antalya, better known as Yayla Seracılığı. However, Verticillium wilt has been frequently observed in the grafted tomato growing greenhouses of the region in recent years. The goal of this thesis study is to identify and characterize the new races, vegetative compatibility groups and pathotypes of V.dahliae in the region by molecular methods. For this purpose, more than 40 greenhouses were visited and one infected sample representing each greenhouse was collected from the grafted tomatoes displaying the symptoms of Verticillium wilt. The samples were obtained from the tomato varieties grafted onto Beaufort F1, Arazi F1, Superpro F1, Armstrong F1, Enpower F1, Kinkong F1 tomato rootstocks. Out of 40 samples, 29 V.dahlia isolates were recovered and purified for molecular studies. All 29 isolates obtained from the grafted tomatoes were amplified with species-spesific primer pair DB19/DB22 to confirm the identity of each isolate to V.dahliae in PCR amplifications. The primer pairs VdAve1F/VdAve1R and VdR2F/VdR2R were used to identify race1 and race2 isolates of the fungus. The pathotypes of each isolates were determined by amplifications with primer pairs VDF/VDR, VNDF/VNDR. The primer pairs DB19/Espdef01, INTND2F/INTND3R, INTND2F/INTND2R, INTND2F/MCR2B were employed to place the isolates into vegetative compatibility groups. The results of the study confirmed that all 29 isolates obtained from the greenhouses of the Elmalı district belonged to fungus V.dahliae. Out of 29 isolates, 23 isolates were determined to be race 2, indicating that this race is dominant in the region. The analysis also showed that VCG1A was the most common vegetative compatibility group (VCG) among the isolates from the tomato production areas of the district. The defoliating (D) pathotypes were dominant pathotypes in the tomato growing greenhouses of Elmalı district.