Microbiome diversity in wheat curl mite genotypes and their role in virus transmission

Wheat streak mosaic virus (WSMV) and Triticum mosaic virus (TriMV) are transmitted by the wheat curl mite (WCM; Aceria tosichella Keifer), impacting US wheat production. In the field, WCM exists as two distinct genotypes (Type-1 and Type-2), and they differ in their ability to transmit WSMV and TriMV. WSMV is transmitted by Type-2 mites with higher efficiency than Type-1. TriMV is only transmitted by Type-2 mites. The reason behind this differential transmission is unknown. One possible explanation could be the presence and influence of diverse microbiomes in both mite types. We hypothesize that the microbiome of Type-2 WCM is more diverse than Type-1 WCM. The objective of this study is to compare the microbial communities present in nonviruliferous and viruliferous WCM of each type. To reduce genetic variability, clonal populations of Type-1 and Type-2 mites were established on susceptible wheat plants (cv. Settler CL). Mite genotypes were confirmed using PCR amplification of mitochondrial- and ribosomal-DNA, followed by restriction fragment length polymorphism. Mites reared on mock-inoculated wheat, WSMV-, TriMV- and co-infected wheat were used to identify microbial shifts that may occur based on the presence or absence of viruses. Initial qPCR assay on non-viruliferous WCM suggests that the Type-2 WCM possesses a greater diversity of microbial communities compared to the Type-1 WCM. Ongoing research includes shotgun metagenome sequencing to identify microbial communities (bacteria, viruses, eukaryotes) present in both nonviruliferous and viruliferous WCM. This research will improve our understanding of microbial interactions underlying WCM-mediated virus transmission.