|THINAKARAN, JENITA - Texas A&M Agrilife|
|PIERSON, ELIZABETH - Texas A&M University|
|KUNTA, MADHURABABU - Texas A&M University|
|Munyaneza, Joseph - Joe|
|RUSH, CHARLIE - Texas A&M Agrilife|
|HENNE, DON - Texas A&M Agrilife|
Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/26/2015
Publication Date: 7/7/2015
Citation: Thinakaran, J., Pierson, E., Kunta, M., Munyaneza, J.E., Rush, C.M., Henne, D.C. 2015. Silverleaf nightshade (Solanum elaeagnifolium), a reservoir host for Candidatus Liberibacter solanacearum, the putative causal agent of zebra chip disease of potato. Plant Disease. 99:910-915.
Interpretive Summary: Potato psyllid is the insect vector of the bacterium that causes zebra chip, a new and economically important disease of potato in the United States. Researchers at USDA-ARS Wapato in Washington, in collaboration with scientists at Texas A&M University, assessed the role of silverleaf nightshade, a common weed in Texas and a host for the potato psyllid, in zebra chip disease spread. It was determined that silverleaf nightshade plants can serve as a reservoir for the zebra chip pathogen, providing a source of infective psyllids colonizing potato crops. This finding underscores the importance of eradicating or managing silverleaf nightshade plants growing in the vicinity of potato fields to prevent disease spread and damage caused by zebra chip.
Technical Abstract: Zebra chip disease of potato is caused by the bacterial pathogen ‘Candidatus Liberibacter solanacearum’ (Lso) and is a growing concern for commercial potato production in several countries in North and Central America and New Zealand. Lso is vectored by the potato psyllid, Bactericera cockerelli, which transmits the pathogen to several cultivated and wild solanaceaous host plants. Silverleaf nightshade, Solanum elaeagnifolium (SLN), is a common weed in the Lower Rio Grande Valley (LRGV) of Texas and a host for both the potato psyllid and Lso. SLN plants were successfully inoculated with Lso under laboratory conditions. Retention studies demonstrated that Lso-infected SLN planted in the field in January 2013, concurrent with commercial potato planting, retained the pathogen under field conditions throughout the year despite extensive dieback during summer. The presence of Lso was confirmed in leaves, roots and stolons of SLN plants collected the following year using PCR. Acquisition assays using B. cockerelli adults also revealed that SLN retained the pathogen. Transmission studies determined that B. cockerelli can acquire Lso within a two week-acquisition access period on Lso-infected SLN and subsequently transmit the pathogen to potato. These results demonstrate that SLN plants can serve as a reservoir for Lso, providing a source of inoculum for B. cockerelli adults colonizing potato the next season. The presence of SLN plants all year-round in the LRGV makes the weed an epidemiologically important host. These findings underscore the importance of eradicating or managing SLN plants growing in the vicinity of potato fields to prevent spread of Lso and damage caused by zebra chip.