Published 2017-05-15
Abstract
The systemic movement of Candidatus Liberibacter asiaticus (CLas) in citrus trees remains partially unresolved. Here, we report on additional experiments conducted in an effort to elucidate the mechanisms of HLB pathogenicity. Our results based on grafting and girdling experiments confirmed that CLas (or a genetic component) can spread within the xylem tissue. By blocking phloem transport and testing additional phloem-free tissues, we also confirmed that CLas genetic components detectable by qPCR analysis are capable analysis are capable of moving through plasmodesmata connections of living cells, but not by apoplastic pathways as evidenced by its absence in pollen, embryo, and nectar. The data in this communication support the presence of alternative pathways for the spread of HLB within citrus trees