Identification of four distinct 'Candidatus Phytoplasma' species in pomegranate trees showing witches' broom, little leaf and yellowing in Jordan, and preliminary insights on their putative insect vectors and reservoir plants. (5th September 2022)

• Record Type: Journal Article
• Authors: Abu Alloush, Asem Habes; Bianco, Piero Attilio; Amashah, Sadeer; Busato, Enrico; Mahasneh, Amre; AlShoubaki, Mahmoud; Alma, Alberto; Tedeschi, Rosemarie; Quaglino, Fabio
• Is Part Of: Annals of applied biology. Volume 182:Number 2(2023)
• Page Start: 159
• Page End: 170
• Publication Date: 2022-09-05
• Subjects: 'Candidatus Phytoplasma asteris' -- 'Candidatus Phytoplasma aurantifolia' -- 'Candidatus Phytoplasma solani' -- 'Candidatus Phytoplasma ulmi' -- Macrosteles sexnotatus; Crop science -- Periodicals; Plants, Protection of -- Periodicals; Crops -- Ecology -- Periodicals; 630
• DOI: 10.1111/aab.12803
• Languages: English
• ISSNs: 0003-4746

Abstract

Abstract: During field surveys conducted in northern Jordan from June to November 2020, phytoplasma‐like symptoms, including leaf yellowing/reddening and rolling, little leaf and witches' broom were observed in pomegranate. Disease incidence in 22 surveyed orchards ranged from 30% to 65%. Nested PCR‐based amplification of 16S rRNA gene detected phytoplasmas in 17% of collected symptomatic pomegranate trees. Amplicon nucleotide sequence analyses allowed attributing the detected phytoplasmas to ' Candidatus Phytoplasma solani', ' Ca. P. aurantifolia', ' Ca. P. asteris' and ' Ca. P. ulmi'. These phytoplasmas were found in plants showing specific symptoms and differentially distributed in the considered locations. Additionally, three cicadellids ( Macrosteles sexnotatus, Cicadulina bipunctata and Psammotettix striatus ) and two non‐crop plants ( Plantago major and Capsicum annuum ) resulted hosting ' Ca. P. asteris' strains, and one cicadellid ( Balclutha incisa ) was carrying a ' Ca . P. solani' strain. A new pomegranate disease complex associated with multiple phytoplasmas, including ' Ca . P. aurantifolia' and ' Ca . P. ulmi', never reported before in this host plant, is described here. Moreover, preliminary indications are provided on its possible epidemiology in Jordan, involving two putative insect vectors ( M. sexnotatus, B. incisa ) first reported in the Country. Abstract : PCR‐based amplification and sequence analyses of 16S rRNA gene detected ' Candidatus Phytoplasma solani', ' Ca . P. aurantifolia', ' Ca . P. asteris' and ' Ca . P. ulmi' in pomegranate trees showing phytoplasma‐like symptoms (leaf yellowing/reddening and rolling, little leaf and witches' broom) in Jordan. Three cicadellids ( Macrosteles sexnotatus, Cicadulina bipunctata and Psammotettix striatus ) and two non‐crop plants ( Plantago major and Capsicum annuum ) resulted hosting ' Ca . P. asteris' strains, and one cicadellid ( Balclutha incisa ) was carrying a ' Ca . P. solani' strain. Further studies are needed to verify the diffusion of pomegranate phytoplasma‐associated diseases in the region and demonstrate the transmission capability of the identified phytoplasma positive insects.