Detection and geographical distribution of Whitefly-transmitted geminiviruses (WTGs) in cucumber and tomato's greenhouses in the major cucurbit growing areas in Iran

In recent years, different whitefly transmitted viruses associated or involved in yellowing symptoms have been reported from greenhouse- and open field-grown cucumber and tomato, worldwide. In Iran, yellowing symptoms and high population of whiteflies have been observed in many cucumber and tomato grown greenhouses, too. In this study, intensive surveys were conducted in the major cucumber and tomato growing areas (greenhouses) in ten provinces of Iran: Khorasan-Razavi, Tehran, Semann, Isfahan, Yazd, Fars, Kerman, Bushehr, Hormozgan, and Khuzestan. Cucumber and tomato leaf samples (n=535, 375, respectively) showing yellowing, thickening and chlorotic symptoms were collected and tested for the presence of most important and prevalent viruses such as Cucumber chlorotic yellows virus (CCYV), Cucumber vein yellowing virus (CVYV), Cucurbit yellow stunting disorder virus (CYSDV), Tomato chlorosis virus (ToCV) and Tomato infectious chlorosis virus (TICV) which associated or involved in yellowing symptoms, using double/triple-antibody sandwich enzyme-linked immunosorbent assay (DAS/TAS-ELISA) and reverse transcriptase polymerase chain reaction (RT-PCR). DAS/TAS-ELISA and RT-PCR results confirmed the presence of viral infection in cucumber greenhouses and showed the infection of collected samples (~38%) to: CCYV, CVYV, and CYSDV. CCYV and CVYV were not detected in Bushehr and CYSDV in Hormozgan provinces. The majority of the collected cucumber leaf samples were infected by CCYV and CVYV (42%), and low infection of samples was related to CYSDV (24%). The major rate of infection to CCYV, CYSDV, and CVYV related in samples where collected from Semnan, Bushehr, and Hoemozgan provinces was 90, 57, and 81%, respectively. Mixed infections were also found in 59% of the symptomatic samples. Double infection was the most mixed infection (CCYV+CYSDV, 45%). DAS/TAS-ELISA and RT-PCR results showed that 40% of tomato samples were infected with ToCV and was detected in all surveyed regions. This is the first report of the ToCV from Iran. TICV was not detected in tomato leaf samples. The major rate of infection to ToCV related in tomato samples collected from Isfahan, Semnan, and Tehran provinces was 75, 58, and 53%, respectively. These results confirmed the presence of whitefly transmitted viruses in associated with yellowing symptoms in the major cucumber and tomato greenhouses in Iran.