Abstract
Citrus huanglongbing (HLB) is currently the greatest threat to the Florida citrus industry. Many efforts are focused on the development of methods to detect this disease in early stages. This research focuses on the characterization of metabolite differences between healthy and HLB-infected leaves. A visual infection scale based on the appearance of infected ‘Valencia’ orange leaves was created to determine the intensity of the symptoms. Results obtained from HPLC-MS showed three marked chromatogram zones in which there was a significant variation of certain compounds with increasing HLB infection scale value. Some early and mid eluting compounds had an increase in peak areas, whereas other late eluting compounds such as chlorophyll derivatives had a reduction in peak areas with increasing infection scale value. Most of the compounds showed mass to charge ratio values between 50 and 800 units. GC-MS, HPLC-MS-MS, and 2D electrophoresis are currently being performed for better compound identification and protein characterization. Further research is needed to differentiate HLB-induced variations from other stress-induced variations that may cause similar changes in citrus leaves.
