|Munyaneza, Joseph - Joe|
|DE LA ROSA-LOZANO, GYNKGO|
Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/13/2009
Publication Date: 6/1/2009
Citation: Munyaneza, J.E., Sengoda, V.G., Crosslin, J., De La Rosa-Lozano, G., Sanchez, A. 2009. First Report of Candidatus Liberibacter psyllaurous in Potato Tubers with Zebra Chip Disease in Mexico. Plant Disease. 93:552.
Interpretive Summary: Zebra chip (ZC) is an emerging and damaging potato disease that is causing millions of dollars in losses to the potato industry in the southwestern United States, Mexico, Central America, and New Zealand. In US and New Zealand, this potato disease has recently been associated with the potato psyllid and a new species of the bacterium Liberibacter, but the disease causal agent in Mexico has not yet been identified. Researchers at USDA-ARS Wapato and Prosser, in collaboration with scientists at Universidad Autonoma de Coahuila and Sabritas, Inc. in Mexico are conducting studies to determine the ZC causal agent in Mexico. For the first time, it was discovered that, in Mexico, zebra chip disease of potato was associated in part with a bacterium found in potatoes in the US and New Zealand. Information from this research directs research to determine the causal agents of this important disease.
Technical Abstract: Zebra Chip (ZC), a new and emerging disease of potato (Solanum tuberosum L.) in southwestern US, México, and Central America, is causing losses of millions of dollars to the potato industry. Recently, this damaging potato disease was also documented in New Zealand. Recent studies conducted in US and New Zealand have associated ZC with a new species of Candidatus Liberibacter vectored by the potato psyllid, Bactericera cockerelli Sulc. Although ZC was first documented in potato fields around Saltillo in México in 1994, this potato disease is strongly believed to be caused by phytoplasmas in that country. To investigate whether Liberibacter is associated with ZC in México, 11 potato (cv. Atlantic) tuber samples exhibiting strong ZC symptoms and 6 asymptomatic tubers were collected from a ZC-infected commercial potato field near Saltillo City, Coahuila, México in September 2008, and tested for this bacterium by PCR. Total DNA was extracted from both symptomatic and asymptomatic tubers and tested by PCR using primer pairs OA2/OI2c and CL514F/R. Also, the samples were tested for phytoplasmas by nested PCR using universal primer pairs P1/P7 and fU5/rU3. Seven out of 11 (63.7%) ZC-symptomatic tubers and one (16.7%) of the asymptomatic potatoes tested positive for Liberibacter. Amplicons generated from symptomatic tubers using each Liberibacter pair of primers were cloned and sequenced. BLAST analysis showed 100 and 98% identity to Liberibacter detected in potatoes from Dalhart (TX) and Garden City (KS) and to Liberibacter detected in several solanaceous plants in New Zealand. Phytoplasmas were detected in 3 out of 11 ZC symptomatic potato tubers, including those infected with Liberibacter. These results suggest that mixed infections of Liberibacter and phytoplasmas occur in ZC-infected potatoes. To our knowledge, this is the first report of Ca. Liberibacter associated with ZC-infected potatoes in México.