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

• DOI: 10.1007/s10658-021-02234-7
• Publication Date: 2021-02-19T20:51:53Z
• Authors: Maritza Luis-Pantoja; Camilo Paredes-Tomás; Youri Uneau; Wayne Myrie; Raphael Morillon; Eleonora Satta; Nicoletta Contaldo; Francesco Pacini; Assunta Bertaccini
• Keywords: 0301 basic medicine; Citrus; maladie bactérienne; Phytoplasma; ‘Candidatus Phytoplasma’, ‘Candidatus Liberibacter’ , mixed infections, citrus; http://aims.fao.org/aos/agrovoc/c_3406; http://aims.fao.org/aos/agrovoc/c_770; Candidatus; Huanglongbing; http://aims.fao.org/aos/agrovoc/c_26802; Plant Science; Horticulture; Gene; Biochemistry; Agricultural and Biological Sciences; Hemiptera; 03 medical and health sciences; http://aims.fao.org/aos/agrovoc/c_5962; phytoplasme; http://aims.fao.org/aos/agrovoc/c_3081; Genetics; Biology; H20 - Maladies des plantes; http://aims.fao.org/aos/agrovoc/c_4035; Bacteria; Plant Pathogens and Insect Vectors; http://aims.fao.org/aos/agrovoc/c_1637; http://aims.fao.org/aos/agrovoc/c_1997; http://aims.fao.org/aos/agrovoc/c_27187; Botany; Life Sciences; maladie des plantes; Cacao Agroforestry Management and Conservation; Polymerase chain reaction; 3. Good health; http://aims.fao.org/aos/agrovoc/c_3352; Citrus greening; Insect vectors; Mixed infection; Molecular detection; Phloematic bacteria; bactérie gram négatif; Diaphorina citri; Insect Science; FOS: Biological sciences; Rootstock; Cultivar; Citrus greening . Phloematic bacteria . Molecular detection . Mixed infection . Insect vectors; Insect Symbiosis and Microbial Interactions; Candidatus Liberibacter; Restriction fragment length polymorphism; 16S ribosomal RNA

Abstract“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.