Gut compartments and ovary bacterial symbionts of the Sunn pest

Abstract

• Sunn pest gut bacterial symbionts are polyphyletic. • Sunn pest symbionts belonging to Firmicutes, Tenericutes, and Proteobacteria. • Gut V1 harbor Enterococcus and V2 and V3 were inhabited by Acetobacteraceae. • Gut V4 harbor Pantoea and Spiroplasma. • Hindgut and ovary nurture Spiroplasma and Pantoea , respectively. The Sunn pest, Eurygaster integriceps (Hemiptera: Scutelleridae), is the severe pest of cereals, especially of wheat in many parts of the world. Many insect species, including the Sunn pest that feed solely on nutritionally restricted diets, harbor symbiotic microorganisms. In the current study, we isolated and identified the Sunn pest bacterial symbionts of gut fractions and ovary. The phylogenetic analysis indicated that Sunn pest gut bacterial symbionts are polyphyletic and contained a taxonomic diversity belonging to three different phyla, including Firmicutes, Tenericutes, and Proteobacteria. Firmicutes was represented by Enterococcus, Proteobacteria by Pantoea and Acetobacteraceae, and Tenericutes by Spiroplasma. We isolated and identified Enterococcus , Acetobacteraceae, Spiroplasma and Pantoea from Sunn pest different gut compartments, and Pantoea from ovaries. There was considerable overlap between recognized symbionts from the 2nd and 3rd midgut sections (Acetobacteraceae), the 4th midgut section and hindgut ( Spiroplasma ), and 4th midgut section and ovary ( Pantoea ). Niche heterogeneity within a microbial habitat of gut fractions resulted in colonizing and adaptation of various communities of symbionts in each fraction. The Sunn pest gut compartments and ovary symbionts have been demonstrated to be of multiple evolutionary origins. This diversity may be of great importance to the Sunn pest fitness and survival in various overwintering niches.