Engineering Citrus Tolerance/Resistance against HLB, a Chronic Immune Disease, Via CRISPR Genome Editing

Citrus Huanglongbing (HLB) caused by Candidatus Liberibacter asiaticus (CLas) is one of the most devastating citrus diseases worldwide. Here, I will present our progress in improving citrus tolerance/resistance against HLB via CRISPR genome editing. Specifically, I will present our current progress in understanding the virulence mechanism of HLB and identification of the suitable target genes for genome editing. CLas triggers systemic and chronic immune responses, including reactive oxygen species (ROS) production and callose deposition, leading to phloem cell death and HLB symptoms. We have recently found the genetic evidence for such a disease model. The transgene-free CRISPR citrus genome editing technology is being used for generating transgene-free, HLB resistant/tolerant citrus varieties. The progress in editing the key genes responsible for the HLB disease development will be presented.