Identification of glassy winged sharpshooter, Homalodisca coagulata, endosymbionts utilizing in situ labeling by light and electron microscopy

Homalodisca coagulata, commonly referred to as the glassy winged sharpshooter (GWSS), is a significant agricultural pest in the vineyard industry of California, and more recently Texas, causing millions in damages. These insects house bacterial endosymbionts in insect cells called bacteriocytes, which are contained inside special organs known as bacteriomes. Studies have indicated that the bacterial endosymbionts are vital to host survival. Molecular methods have revealed the presence of two types of co-primary bacterial endosymbionts within the GWSS: the gamma-proteobacteria, Candidatus Baumannia cicadellinicola, and the Chlamydia, Candidatus Sulcia muelleri. In previous studies, we have utilized fluorescently labeled rDNA probes in conjunction with fluorescent in situ hybridization (FISH), and laser scanning confocal microscopy to localize these bacterial endosymbionts in situ in the bacteriomes. Our data supports previously published results, which indicate that Sulcia bacteria are pleomorphic in shape and cell wall deficient, while the Baumannia are coccoid shaped and have typical Gram-negative morphology. Currently, we are using a combination of digoxigenin labeled 16S rDNA probes, in situ hybridization, immunocytochemistry, and transmission electron microscopy (TEM) to correlate species identification with ultrastructural morphology.