Deep 16S rRNA gene sequencing of anterior foregut microbiota from the blue-green sharpshooter (Graphocephala atropunctata)
Graphocephala atropunctata or the blue-green sharpshooter (BGSS) has been long recognized as the principal native vector of Xylella fastidiosa in coastal, wine-grape-growing areas of California. X. fastidiosa is the causative agent of Pierce's disease of grapevine and of numerous other leaf-scorching diseases of agronomically important plants. X. fastidiosa has been shown to colonize the cibarium and precibarium (anterior foregut) of sharpshooters, where it may encounter other naturally occurring bacterial species. Here, deep 16S rRNA sequencing was used to survey the microbiota associated with the BGSS anterior foregut. DNA was extracted from dissected cibaria and precibaria; a portion of the 16S rRNA gene was amplified and sequenced using Illumina MiSeq technology. An average of approximately 32 000 sequence reads per insect was obtained. Agrobacterium was the most common genus detected; additional sequencing of the full-length 16S rRNA gene further identified this as Agrobacterium tumefaciens or A. fabrum. A number of additional plant-associated bacterial genera were also detected (Pseudomonas and Ensifer), along with genera known to be associated with insects (Baumannia), and soil (Stenotrophomonas, Caulobacter, Delftia, Achromobacter, Acinetobacter and Novosphingobium). Approximately half of the genera reported here have been previously reported to be prevalent in the cibarium and precibarium of glassy-winged sharpshooter (GWSS; Homalodisca vitripennis). Many of these cibariumand precibarium-associated genera likely interact with X. fastidiosa.