The Citrus Genome: Past, Present and Future

Abstract

Within this introductory chapter, I would like to briefly discuss the contribution of the genomic revolution to the science of Citrus. Genomics undoubtedly plays a central role in the ongoing reconstruction of evolutionary history of the Citrus clade, but elucidation of the role played by man in the more recent wandering and distribution of citrus relies on other disciplines, such as Archaeobotany and Historic documentation. As to the current challenges faced by the Citrus Industry, the most serious threat of the 21st century is the pandemic, devastating HLB disease. In this case implementation of the genomic tools has not yet lead to a real breakthrough. Can anything meaningful be said about the future? Two major frontiers are evident; breeding and physiology. Modern plant breeding includes by now techniques for precise editing of the genome, which hold a bright promise for targeted crop improvement. The term ‘physiology’ means, in this context, an advanced understanding of all the developmental and biochemical traits responsible for the citrus phenotype. This is a tremendous challenge, since the citrus phenome is still rather mysterious, even the genetic basis of the ‘Hesperidium’ fruit unit is as yet poorly understood.