Phytopathogenic Mollicutes

Hemipteran insects are known to be dependent on bacterial endosymbionts for survival. Haplaxius crudus is the vector of ‘Candidatus Phytoplasma palmae’ associated with lethal yellowing disease that affects more than 40 Arecaceae species around the world. In this study the bacterial composition of field-collected H. crudus is defined using high-throughput 16S rRNA gene sequencing. Insects either negative or positive to lethal yellowing phytoplasmas enclosed in 16SrIV-A and 16SrIV-D subgroups were analyzed. A total of 141 amplicon sequence variants (ASVs) distributed in seven phyla, 13 classes, 29 orders, 51 families, and 72 genera of bacteria were detected. The Bacteroidetes phylum was the dominant group followed by Proteobacteria and Tenericutes. Five endosymbionts not previously reported and with contrasting abundances, including the primary endosymbiont, ‘Ca. Sulcia muelleri’, ‘Ca. Cardinium’, Arsenophonus nasoniae, Lariskella sp., and Achromobacter xylosoxidans were identified. ‘Ca. S. muelleri’ was the dominant endosymbiont. Metagenome prediction revealed key functions of endosymbionts for the host, such as the synthesis of amino acids, sugars, vitamins, among others. These results provide insights into the endosymbionts of H. crudus and new information concerning the bacterial community of insect vectors of phytoplasmas with economic relevance such as lethal yellowing disease.