Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/19/2014
Publication Date: 9/14/2014
Citation: Li, R., Ling, K. 2014. Screening tomato germplasm for resistance to potato spindle tuber viroid. Meeting Abstract. September 14-17, 2014. Page 8.
Interpretive Summary: N/A
Technical Abstract: In recent years, several outbreaks of a potentially devastating viroid disease on tomato in North America have caused serious concerns to tomato growers and vegetable seed industry. Several closely related viroids in the genus Pospiviroid have been identified on tomato. Among them, Potato spindle tuber viroid (PSTVd) is one of the most prevalent species which induces severe plant stunting, leaf chlorosis, resulting in none or smaller misshaped fruits. To assess genetic resistance to PSTVd, we screened 100 accessions of the tomato core collection from the Tomato Genetics Resource Center, including one Solanum arcanum, 17 S. chilense, five S. corneliomulleri, 27 S. habrochaites, 20 S. lycopersicum, two S. huaylasense, 24 S. peruvianum, and four S. pimpinellifolium. For each accession, 6-12 seeds were germinated on potting soil in a greenhouse. Two-week after germination, seedlings were inoculated mechanically with an inoculum that was prepared with a PSTVd-infected tomato leaf tissue. To ensure no escape, a second inoculation was carried out within a week following the first inoculation. Reading of symptoms on the inoculated plants was conducted 4-6 weeks post inoculation. Confirmation of PSTVd was carried out with real-time RT-PCP using a simplified crude leaf extract (1:1000 w/v) for RNA temperate. Those accessions with none to less than 50% positive were evaluated for a second time. Some promising lines in the second test were subjected to a third experiment. All the inoculated tomato plants in the control (S. lycopersicum ‘Rutgers’) as well as accessions listed above from S. Arcanum, S. corneliomulleri, S. lycopersicum, S. huaylasense and S. pimpinellifolium were infected by PSTVd. However, a number of accessions in S. chilense, S. habrochaites, and S. peruvianum showed none to partial infection. Upon three consecutive experiments, no immunity was identified in the current test. Four accessions (including 2 S. chilense and 2 S. habrochaites) showed less than 50% of PSTVd infection. Currently, seed reproductions on the resistant plants are underway, which will be used to test for possible genetic inheritance of resistance.