Variations in Zebra Chip Disease Expression and Tuber Biochemistry in Response to Vector Density.
Zebra chip (ZC) disease, caused by 'Candidatus Liberibacter solanacearum', which is transmitted by the potato psyllid, has negatively affected potato production in the United States for over a decade. The present study was conducted to evaluate the affect of the number of bacteriliferous psyllids on 'Ca. L. solanacearum' titer, levels of amino acids, carbohydrates, phenolics, and, subsequently, symptom severity in potato tubers. 'Red La Soda' and 'Russet Norkotah' potato were planted in the field and later inoculated with 'Ca. L. solanacearum' using 5, 10, and 30 bacteriliferous potato psyllids. In both cultivars, the increase in the number of psyllids resulted in elevated 'Ca. L. solanacearum' titer and symptom severity. In the cases of amino acids and reducing sugars, responses to vector density appeared to be cultivar specific. Overall, phenolic compounds showed a consistent increase following infection, a response that, in most cases, was positively correlated with the number of infective psyllids. Results quantified the impact of the number of infective psyllids on 'Ca. L. solanacearum' titer and biochemical content of infected tubers previously shown to be correlated with the degree of symptom expression. Managing vector numbers is currently the only effective approach for minimizing losses to ZC in grower's fields. However, our findings on physiological responses to vector density suggest that, in combination with chemical control, development of more tolerant or resistant potato genotypes, with emphasis on interrupting pathways that are associated with increased phenolic activity levels, may lead to more sustainable management of ZC in the future.
First author: University of Idaho, Department of Plant, Soil, and Entomological Sciences, Aberdeen Research & Extension Center, Aberdeen 83210; second author: United States Department of Agriculture-Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Crop Diseases, Pests and Genetics Research Unit, 9611 S. Riverbend Ave, Parlier, CA 93648; and third, fourth, and fifth authors: Texas A&M Agrilife Research and Extension, 6500 Amarillo Blvd W., Amarillo 79106.
Arash
A
Rashed
First author: University of Idaho, Department of Plant, Soil, and Entomological Sciences, Aberdeen Research & Extension Center, Aberdeen 83210; second author: United States Department of Agriculture-Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Crop Diseases, Pests and Genetics Research Unit, 9611 S. Riverbend Ave, Parlier, CA 93648; and third, fourth, and fifth authors: Texas A&M Agrilife Research and Extension, 6500 Amarillo Blvd W., Amarillo 79106.
Christopher M
CM
Wallis
First author: University of Idaho, Department of Plant, Soil, and Entomological Sciences, Aberdeen Research & Extension Center, Aberdeen 83210; second author: United States Department of Agriculture-Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Crop Diseases, Pests and Genetics Research Unit, 9611 S. Riverbend Ave, Parlier, CA 93648; and third, fourth, and fifth authors: Texas A&M Agrilife Research and Extension, 6500 Amarillo Blvd W., Amarillo 79106.
Fekede
F
Workneh
First author: University of Idaho, Department of Plant, Soil, and Entomological Sciences, Aberdeen Research & Extension Center, Aberdeen 83210; second author: United States Department of Agriculture-Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Crop Diseases, Pests and Genetics Research Unit, 9611 S. Riverbend Ave, Parlier, CA 93648; and third, fourth, and fifth authors: Texas A&M Agrilife Research and Extension, 6500 Amarillo Blvd W., Amarillo 79106.
Li
L
Paetzold
First author: University of Idaho, Department of Plant, Soil, and Entomological Sciences, Aberdeen Research & Extension Center, Aberdeen 83210; second author: United States Department of Agriculture-Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Crop Diseases, Pests and Genetics Research Unit, 9611 S. Riverbend Ave, Parlier, CA 93648; and third, fourth, and fifth authors: Texas A&M Agrilife Research and Extension, 6500 Amarillo Blvd W., Amarillo 79106.
Charles M
CM
Rush
D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D001419:Bacteria / Q000145:classification; D050260:Carbohydrate Metabolism; D006430:Hemiptera; D010636:Phenols / Q000378:metabolism; D010935:Plant Diseases / Q000382:microbiology*; D035281:Plant Tubers / Q000378:metabolism*; D011156:Population Density; D011198:Solanum tuberosum / Q000378:metabolism / Q000382:microbiology*
D000596:Amino Acids; D010636:Phenols