Abstract
The impact of disease outbreaks on the phytosanitary quality of seeds was investigated for two pathosystems: tomato–Xanthomonas vesicatoria and pepper–Xanthomonas euvesicatoria. This study, which was performed in Italy and Serbia, aimed to evaluate the season‐to‐season transmission of phytopathogenic regulated bacteria associated with phytosanitary risks posed by seeds produced in areas where bacterial infections are possible. For each pathosystem, field plots were experimentally inoculated to simulate an initial infection rate of 1%, 5% and 15%. The area under the disease progress curve (AUDPC) was calculated for each field plot, the seeds produced were analysed to determine the contamination level and rate, and the plant‐to‐seed transmission was evaluated by a seedling grow‐out (SGO) assay. To investigate transmission under field conditions, a second‐year experiment was performed, wherein seeds collected from the first year were used to establish new field plots. During the first growing season, AUDPC values were positively correlated with the percentages of initial infection for each pathosystem. Seed contamination levels in pepper ranged from 34 to 100 CFU g−1, and the contamination rate ranged from 1.50% up to 3.17% for X. euvesicatoria, whereas processing and fresh market tomato seeds produced both in Italy and Serbia were not infected by X. vesicatoria. During SGO assays and the second cropping year, no symptoms were observed in either tomato or pepper plants. Therefore, the calculated pepper seed contamination rate for X. euvesicatoria appeared to be less than the threshold necessary to initiate a disease outbreak. Finally, all seeds obtained during the second cropping year were uninfected.
Highlights
Infected seeds are the most important pathway for the introduction and spread of several plant pathogenic bacteria that may affect both fruit quality and plant viability, causing economic losses worldwide (Gitaitis & Walcott, 2007)
Tomato can be affected by bacterial spot caused by Xanthomonas vesicatoria (Xv; Doidge, 1921; Vauterin et al, 1995) and X. euvesicatoria (Xe; Jones et al, 2004)
Certified tomato and pepper seeds were kindly provided by commercial sources: processing tomato seeds were provided by ISI Sementi s.p.a. (Fidenza, Italy), and fresh market tomato and bell pepper seed were provided by NS-SEME (Novi Sad, Serbia)
Summary
Infected seeds are the most important pathway for the introduction and spread of several plant pathogenic bacteria that may affect both fruit quality and plant viability, causing economic losses worldwide (Gitaitis & Walcott, 2007). The latter is aggressive against pepper (Ignjatov et al, 2010) These bacteria are spread through contaminated/ infected seeds as the primary source of inoculum (Dutta et al, 2014) and are listed as quarantine organisms by the European Plant Protection Organization (EPPO). These pathogens can survive in seeds for extended periods (Bashan et al, 1982a); such survival ability allows long-distance dissemination and facilitates their introduction into pathogen-free areas through seed trade. Seed testing and certification (EPPO, 2013) and seed production in pathogen-free areas with no conducive
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
