Variability of Candidatus Liberibacter asiaticus and production of citrus plants with prophage genes

Abstract

Huanglongbing is a major threat to the citriculture worldwide. The fast and efficient dissemination of Candidatus Liberibacter spp. by the psyllid Diaphorina citri, the absence of genetic resistance in Citrus spp., are main factor driving the severity of the disease. In Brazil, we have associated with HLB Ca. L. asiaticus (Las) and Ca. L. americanus (Lam). The development of citrus cultivars with good agronomical traits and resistant to HLB is an efficient, economic and environmental sustainable way to control diseases. However, classical breeding of citrus is a long process, due to the genetic and reproductive aspect of this genus, with the additional aspect of lack of resistance do HLB and to the psyllid. The production of genetically modified citrus resistant to the HLB is an alternative to the difficulties of breeding and to the management practices. This could allow the citriculture to resist to the HLB from the disease and economic point of view and allow Brazil to keep the first place in the ranking of orange juice exporters. Our hypothesis is to control Liberibacter using bacteriocin from Las to control Lam. Diversity analysis will help to understand the predominance in the field of Las isolates. Orthologous genes to the Las bacteriocin from Lam and Ca. L. solanacearum, will also be tested to the control of HLB caused by Las in sweet orange. (AU)