Title: First report of 'Candidatus Liberibacter solanacearum' on tomato in Honduras Authors
Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 21, 2013
Publication Date: May 29, 2013
Citation: Aguilar, E., Sengoda, V.G., Bextine, B., Mc Cue, K.F., Munyaneza, J.E. 2013. First report of 'Candidatus Liberibacter solanacearum' on tomato in Honduras. Plant Disease. 97:1375. Interpretive Summary: Liberibacter is an economically important plant pathogen that severely damages potato, tomato, pepper, and other related crops. This bacterium is transmitted to these crops by the potato psyllid, a serious insect pest in the United States. Researchers at USDA-ARS Wapato, WA and Albany, CA, University of Texas, and Zamorano University in Honduras discovered that this plant pathogen was infecting tomato crops in Honduras, causing significant losses to the tomato industry in the country. Tomatoes constitute an important commodity in Central America; therefore, documentation of this bacterium distribution in this country is important to world food security.
Technical Abstract: In April of 2012, tomato plants grown in several departments of Honduras, were observed with symptoms resembling those of “Candidatus Liberibacter solanacearum” (Lso) infection. The symptoms include overall chlorosis, severe stunting, leaf cupping, excessive branching of axillary shoots, and leaf purpling and scorching. Disease incidence in a number of commercial fields in the affected area ranged from 5 to 50%. Heavy infestations of the psyllid Bactericera cockerelli were observed in the affected fields and this insect has been shown to transmit Lso to potato, tomato and other solanaceous species. Tomato plant samples were collected from two psyllid-infested commercial fields in the municipalities of Danli (Department of El-Paraiso) and Comayagua (Department of Comayagua). Total DNA was extracted from leaf tissues of 70 plants, 50 and 20 symptomatic and asymptomatic plants, respectively, with the CTAB buffer extraction method. The DNA samples were tested for Lso by PCR with primer pairs specific for both 16S rDNA (OA2 and OI2c) and outer membrane protein gene (OMB 1482f and 2086r) of the bacterium. Ten (20%) of the 50 symptomatic tomatoes were positive for Lso using both primer pairs and no asymptomatic plants tested positive for the bacterium. To our knowledge, this is the first report of “Ca. Liberibacter solanacearum” associated with tomato in Honduras. This bacterium has caused millions of dollars in losses to the tomato industry in U.S., Mexico, and New Zealand. Serious damages to tomato crops due to Lso could expand throughout Central America, especially in those countries where B. cokerelli, the pathogen insect vector, occurs.