Survey for phytoplasmas and Candidatus Liberibacter sp. from HLB-like symptomatic citrus plants in Brazil

Abstract

The huanglongbing (HLB) is the most important citrus disease in the world. In Brazil, phytoplasmas from 16SrIX group were associated with symptomatic-HLB citrus plants without Candidatus Liberibacter spp. in São Paulo and Bahia States. This work objectives to investigate the presence of phytoplasmas in HLB-symptomatic citrus plants in other regions of Brazil to monitor the spread of these phytoplasmas and their association with HLB. Leaves of sweet orange, lime and mandarin from commercial citrus orchards in the States of Rio Grande do Sul (RS), Minas Gerais (MG), Distrito Federal (DF), Bahia (BA) and Pará (PA) with HLB-like symptoms were collected and submitted to diagnosis. The PCR or qPCR with specific primers for Ca. Liberibacter asiaticus/ americanus and 16SrIX phytoplasma were used. A total of 150 samples were analyzed from 141 orchards inspected. Group IX phytoplasmas were detected in six samples from Brazlândia-DF. Candidatus Liberibacter asiaticus was detected in MG in the regions of Bonfim, Campanha and Perdões. There was no detection of both 16Sr group IX and Ca. Liberibacter asiaticus in RS, BA and PA, currently HLB-free areas. Moreover, Ca. Liberibacter americanus was not detected in the samples. The survey will continue to elucidate the importance of phytoplasmas in HLB-like symptomatic citrus plants.