Location: Fruit and Vegetable Insect Research
Title: First report of "Candidatus Liberibacter solanacearum" on pepper in Honduras Authors
Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 19, 2013
Publication Date: July 31, 2013
Citation: Munyaneza, J.E., Sengoda, V.G., Aguilar, E., Bextine, B., Mc Cue, K.F. 2013. First report of "Candidatus Liberibacter solanacearum" on pepper in Honduras. Plant Disease. http://dx.doi.org/10.1094/PDIS-06-13-0598-PDN. Interpretive Summary: Liberibacter is an economically important bacterium that severely damages several crops including potato, tomato, and other related crops. This plant pathogen is transmitted to these crops by the potato psyllid, a serious insect pest in the United States, Mexico, Central America, and New Zealand. Researchers at USDA-ARS Wapato, WA and Albany, CA, University of Texas, and Zamorano University in Honduras discovered for the first time that this bacterium was infecting pepper crops in Honduras, posing a serious threat to the vegetable industry in the country. Ultimately, effective monitoring and management of this plant pathogen and its insect vector will prevent serious damage they cause to economically important crops worldwide.
Technical Abstract: In 2012, bell pepper (Capsicum annuum) plants exhibiting symptoms that resembled those of the bacterium “Candidatus Liberibacter solanacearum” infection were observed in commercial pepper fields in several departments in Honduras, including Francisco Morazán, Ocotepeque, El Paraíso, and Olancho. Many of the fields were infested with the psyllid Bactericera cockerelli, a vector of “Ca. L. solanacearum”. The plants exhibited chlorotic or pale green apical growth and leaf cupping, sharp tapering of the leaf apex, shortened internodes, and an overall stunting. All cultivars grown were affected and 20 to 75% of plants in each field were symptomatic. Pepper plant samples were collected from a total of eight affected fields. Total DNA was extracted from the top whole leaf tissue of a total of 19 plants, including 14 symptomatic and five asymptomatic pepper plants, with the CTAB buffer extraction method. The DNA samples were then tested by PCR using specific primer sets OA2/OI2c and OMB 1482f/2086r, to amplify a portion of 16S rDNA and the outer membrane protein (OMB) genes, respectively, of “Ca. L. solanacearum”. OMB gene and 16S rDNA fragments of 605 and 1168 bp, respectively, were amplified from the DNA of 7 of 14 symptomatic plants with each primer set, indicating the presence of “Ca. L. solanacearum”. No “Ca. L. solanacearum” was detected in the asymptomatic plants. Further cloning and sequencing of the amplified products confirmed presence of the bacterium in the pepper plants. To our knowledge, this is the first report of “Ca. L. solanacearum” associated with pepper crops in Honduras.