Identification of ‘Candidatus Phytoplasma’ species in “huanglongbing” infected citrus orchards in the Caribbean

• Published in: European journal of plant pathology Vol. 160; no. 1; pp. 185 - 198
• Main Authors: Luis-Pantoja, Maritza, Paredes-Tomás, Camilo, Uneau, Youri, Myrie, Wayne, Morillon, Raphael, Satta, Eleonora, Contaldo, Nicoletta, Pacini, Francesco, Bertaccini, Assunta
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-05-2021; Springer Nature B.V
• Subjects: Agriculture; Biomedical and Life Sciences; Candidatus Liberibacter; Candidatus Phytoplasma; Cultivars; Diaphorina citri; Ecology; Fruits; Infections; Insects; Life Sciences; Mixed infection; Orchards; Pathogens; Phytoplasma; Plant bacterial diseases; Plant Pathology; Plant Sciences; Signs and symptoms; Species; Cuba; Caribbean area; Jamaica; Guadeloupe; Citrus greening; Mixed infection; Molecular detection; Insect vectors; Phloematic bacteria
• DOI: 10.1007/s10658-021-02234-7
• EISSN: 1573-8469
• ISSN: 0929-1873

“Huanglongbing” (HLB) is one of the most devastating diseases of citrus orchards worldwide. Samples from 183 citrus plants of different cultivars and rootstock/cultivar combinations, showing HLB symptoms in three Caribbean countries (Cuba, Jamaica, and Guadeloupe-France), were collected to verify the possible co-infection of ‘
Candidatus
Phytoplasma’ and ‘
Candidatus
Liberibacter’ species. The 64% of the samples resulted positive to the ‘
Ca
.
L. asiaticus
’ and the 27% to diverse ‘
Ca
. Phytoplasma’-related species, moreover about the 14% of the samples infected with ‘
Ca
. Liberibacter’ were also found positive to phytoplasmas, indicating the presence of mixed infection especially in the orchards located in Cuba. Moreover, in one of the samples from Jamaica mixed phytoplasma infection was detected. Moreover the detection of only phytoplasmas in 11 symptomatic citrus samples collected from Cuba and Guadeloupe without ‘
Ca
. Liberibacter’ detection, confirmed that the symptomatology cannot be the sole criterium to discriminate between the presence of the two pathogens, and molecular detection is necessary to identify single or mixed infections.
Diaphorina citri
insects collected from Cuba and Guadeloupe resulted infected with ‘
Ca
. L. asiaticus’ confirming its active role in the dissemination of the pathogen. Only one insect of the
Cicadidae
family, collected in Guadeloupe, was found positive for phytoplasma presence. Considering that the phytoplasmas belonging to some ‘
Candidatus
species’ were detected in the three countries in different citrus varieties, a relevant role as phytoplasma reservoir can be attribute to citrus orchards.