Graduate Research Assistant (GRA) University of Florida Lake Alfred, Florida
Body of Abstract: Citrus Huanglongbing (HLB), also known as citrus greening disease, is caused by the phloem-colonizing bacterium Candidatus Liberibacter asiaticus (CLas) and is vectored by the Asian citrus psyllid Diaphorina citri. HLB is the most devasting citrus disease worldwide. CLas triggers systemic and chronic production of reactive oxygen species (ROS) which causes cell death of phloem tissues. Antioxidant enzymes are responsible for scavenging ROS and minimizing oxidative damage. Both ascorbate peroxidase (APX) and superoxide dismutase (Cu-Zn SOD) are antioxidant enzymes. Specifically SODs catalyze the dismutation of O2− into O2 and H2O2; whereas APXs convert H2O2 to H2O. We hypothesize that overexpressing APX and SOD could reduce the harmful effects of ROS thus mitigate HLB symptoms. In this study, we generated Citrus sinensis cv. Hamlin lines that overexpress APX and SOD genes in combination. The overexpressing lines will be inoculated with CLas to test their effect on ROS production, callose deposition, cell death of phloem tissues, and HLB symptoms triggered by CLas.