Profiling the eukaryotic microbiome of Schizaphis graminum biotypes E and K in response to host plant species, cultivar, and elapsed time

Authors: Crane, Yan; CRANE, CHARLES - US Department Of Agriculture (USDA); ANCIRA, JACOB - Microgen Bioproducts; TIPTON, CRAIG - Microgen Bioproducts; Schemerhorn, Brandon

Submitted to: Popular Publication
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/24/2026
Publication Date: N/A
Citation: N/A

Interpretive Summary: In recent years, more attention has been paid to the microbial and fungal co-inhabitants of many organisms, including humans, plants and insects. In many cases, these symbiotic organisms play an important role in maintaining the well-being of their host. Greenbug is an aphid that is known to affect multiple grass species, including important crops (wheat, barley, sorghum and rye) either through physical damage to the plant by their feeding, or the viruses they transmit. Increasing our understanding of the endosymbionts hosted by this insect is necessary for controlling infestations. This study looks at the diversity of the fungal symbiotes of Greenbug using a molecular marker common to all fungi. Some fungi were present in all samples, indicating that these are necessary for greenbug survival.

Technical Abstract: The fungal microflora of two biotypes, E and K, of greenbug aphid (Schizaphis graminum) was investigated with amplification of the internal transcribed spacer region in ribosomal RNA genes. The effects of biotype, host plant species, days post infestation, host plant cultivar, and host plant susceptibility to greenbug feeding, were analyzed for greenbugs feeding on 17 cultivars in wheat, rye, barley, sorghum, and Aegilops triuncialis. ANOVA demonstrated that the first three of these factors significantly influenced the microflora. Filamentous ascomycetes and tremellomycete yeasts dominated the diverse microflora, which ranged from 223 operational taxonomic units in sorghum to 277 operational taxonomic units in Aegilops triuncialis. Prominent genera included Aspergillus, Fusarium, Cladosporium, Linnemannia, Hannaella, and Cryptococcus. Most of the taxa have been previously reported in phylloplane microfloras and in/on other insects. Shannon entropy and Hill1 diversity were greater in biotype E and decreased at the last timepoint. The community in biotype E was more stable with respect to host species and cultivar. Host plant resistance to greenbug feeding had little effect on the fungal microflora.