The Zebra chip (ZC) syndrome is an emerging disease of potato and a major threat to the potato industry. The potato psyllid, Bactericerca cockerelli (Sulc) is believed to be a vector of the ZC pathogen, which is n...The Zebra chip (ZC) syndrome is an emerging disease of potato and a major threat to the potato industry. The potato psyllid, Bactericerca cockerelli (Sulc) is believed to be a vector of the ZC pathogen, which is now thought to be Candidatus Liberibacter, a bacterium. To further understand the relationship between potato psyllid infestation and ZC disease expression, healthy potato plants at different growth stages (4, 6 and 10 weeks after germination) were exposed separately to potato psyllids that were separately reared on four solanaceous hosts plants (potato, tomato, eggplant or bell pepper) for more than 1 year. ZC symptoms, leaf rates and total nonstructural carbohydrate accumulation in leaves and tubers of healthy and psyllid-infested plants were monitored and recorded. Typical ZC symptoms were observed in leaves and tubers of all plants exposed to potato psyllids regardless of the host plant on which they were reared. This was also accompanied by significant reductions in net photosynthetic rate. Caged potato plants without exposure to potato psyllids (uninfested controls) did not show any ZC symptom in both foliage and in harvested tubers. Foliage damage and ZC expression were most severe in the potato plants that were exposed to potato psyllids 4 weeks after germination compared to plants infested at later growth stages. Tubers from potato psyllid-infested plants had significantly higher levels of reducing sugars (glucose) and lower levels of starch than those in healthy plants, indicating that potato psyllid infestation interfered with carbohydrate metabolism in either leaves or tubers, resulting in ZC expression.展开更多
The impacts of potato psyllid (Bactericera cockerelli) feeding on potato foliage on the free amino acids (FAAs) composition in potato leaf and tubers were determined under greenhouse conditions. The free amino aci...The impacts of potato psyllid (Bactericera cockerelli) feeding on potato foliage on the free amino acids (FAAs) composition in potato leaf and tubers were determined under greenhouse conditions. The free amino acids in plant extracts were separated by high-performance liquid chromatography, and in both leaf and tuber samples, at least 17 FAAs were detected. Psyllid feeding significantly changed the levels of several FAAs in both leaf and tuber samples. The concentration of leucine increased 1.5-fold, whereas that of serine and proline increased 2- and 3-fold, respectively. In contrast, the concentrations ofglutamic acid, aspartic acid and lyscine were significantly reduced by 42.0%, 52.1% and 27.5%, respectively. There were also significant changes in the levels of FAAs in the Zebra chip (ZC) infected tubers compared with the healthy tubers, and the levels of six of the FAAs increased, and the levels of nine of the FAAs decreased. The results from this study indicate that potato psyllid causes major changes in free amino acid composition of plant tissues, and this change in plant metabolism may contribute to the plant stress as indicated by increased levels of proline in the leaves and hence promoting the development of plant diseases such as ZC disease.展开更多
文摘The Zebra chip (ZC) syndrome is an emerging disease of potato and a major threat to the potato industry. The potato psyllid, Bactericerca cockerelli (Sulc) is believed to be a vector of the ZC pathogen, which is now thought to be Candidatus Liberibacter, a bacterium. To further understand the relationship between potato psyllid infestation and ZC disease expression, healthy potato plants at different growth stages (4, 6 and 10 weeks after germination) were exposed separately to potato psyllids that were separately reared on four solanaceous hosts plants (potato, tomato, eggplant or bell pepper) for more than 1 year. ZC symptoms, leaf rates and total nonstructural carbohydrate accumulation in leaves and tubers of healthy and psyllid-infested plants were monitored and recorded. Typical ZC symptoms were observed in leaves and tubers of all plants exposed to potato psyllids regardless of the host plant on which they were reared. This was also accompanied by significant reductions in net photosynthetic rate. Caged potato plants without exposure to potato psyllids (uninfested controls) did not show any ZC symptom in both foliage and in harvested tubers. Foliage damage and ZC expression were most severe in the potato plants that were exposed to potato psyllids 4 weeks after germination compared to plants infested at later growth stages. Tubers from potato psyllid-infested plants had significantly higher levels of reducing sugars (glucose) and lower levels of starch than those in healthy plants, indicating that potato psyllid infestation interfered with carbohydrate metabolism in either leaves or tubers, resulting in ZC expression.
文摘The impacts of potato psyllid (Bactericera cockerelli) feeding on potato foliage on the free amino acids (FAAs) composition in potato leaf and tubers were determined under greenhouse conditions. The free amino acids in plant extracts were separated by high-performance liquid chromatography, and in both leaf and tuber samples, at least 17 FAAs were detected. Psyllid feeding significantly changed the levels of several FAAs in both leaf and tuber samples. The concentration of leucine increased 1.5-fold, whereas that of serine and proline increased 2- and 3-fold, respectively. In contrast, the concentrations ofglutamic acid, aspartic acid and lyscine were significantly reduced by 42.0%, 52.1% and 27.5%, respectively. There were also significant changes in the levels of FAAs in the Zebra chip (ZC) infected tubers compared with the healthy tubers, and the levels of six of the FAAs increased, and the levels of nine of the FAAs decreased. The results from this study indicate that potato psyllid causes major changes in free amino acid composition of plant tissues, and this change in plant metabolism may contribute to the plant stress as indicated by increased levels of proline in the leaves and hence promoting the development of plant diseases such as ZC disease.