‘Candidatus Phytoplasma’ and ‘Candidatus Liberibacter’ species detection in citrus

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.

Tropicsafe project: Detection and management of lethal yellowing and grapevine yellows diseases in partner countries

“…In Cuba, the phytoplasma was detected in coconut palms with lethal yellowing; however, also symptomatic palms positive for phytoplasmas belonging to the ribosomal groups 16SrI, 16SrVII and 16SrXII were identified TROPICSAFE project: detection and management of lethal yellowing and grapevine yellows diseases in partner countries (Paredes-Tomás et al, 2019). Moreover, in citrus infected with "huanglongbing" the 16SrIV phytoplasma was found mainly in mixed infection with 'Candidatus Liberibacter asiaticus' or other phytoplasmas in symptomatic plants (Bertaccini et al, 2019;Luis-Pantoja et al, 2021) indicating that in this specific ecosystem citrus could be an alternative host species for LY phytoplasmas. In Mexico transmission trials of 16SrIV phytoplasmas with adults of Haplaxius crudus to Pritchardia pacifica plants confirmed its vector role in this country (Narvaez et al, 2019;Dzido et al, 2020).…”

Possible economic losses on the oranges production chain of Peru due to introduction of Huanglongbing (HLB): Simulation of prospective scenarios to 2045

“…In the United States, it emerged in Florida in 2005 (Lin et al, 2023;Lopez & Durborow, 2014;Zapien-Macias et al, 2022) and California in 2008(McRoberts et al, 2019Nguyen et al, 2023). Cuba reported cases in 2007 (Bertaccini et al, 2019;Paredes-Tomás et al, 2023), and it entered Yucatán, Mexico, in 2009(López-Collado et al, 2013Pérez-Valencia et al, 2019). The Dominican Republic experienced its first cases in 2010 (Luis-Pantoja et al, 2021), followed by Belize in 2011 (Petri & Jorge, 2015) and Argentina in 2012 (Badaracco et al, 2017(Badaracco et al, , 2022Petri & Jorge, 2015).…”