Abstract
Huanglongbing (HLB) is one of the main problems in citrus areas of many orange producing countries. It is caused by the bacterium Candidatus Liberibacter spp. and the symptoms of the disease have been related with the accumulation of callose and phloem proteins (PP2) in the tubes of sieve elements of the phloem of the infected plant. The mechanism of accumulation of PP2 proteins in sieve …