Location: Great Basin Rangelands ResearchTitle: Global spread of wheat curl mite by the most polyphagous and pestiferous lineages) Author
Submitted to: Annals of Applied Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/25/2014
Publication Date: N/A
Citation: Interpretive Summary: The wheat curl mite (WCM) is an important pest of grains that has spread worldwide from its presumed native range in Europe. It causes direct damage to grain crops and also is a known vector of several plant viruses, including wheat streak mosaic virus. The goal of this study was to compare invasive WCM populations from Australia and North and South America to the eight known WCM lineages described in Europe using a combination of host-specificity and DNA fingerprint data. The eight known WCM lineages differ in host range (i.e. generalist vs. host-specific) as well as in the particular host plants that they infest, from grain crops and even bulbs (e.g. onion, garlic) for the most generalist lineages to wild grasses for many of the host-specific lineages. This study revealed that the invasive WCM populations outside of Europe belong to the three lineages that are known to attack grain crops, while lineages that do not attack crops were not found outside Europe. The results highlight the need for extensive surveys for WCM on both crops and wild grasses on continents that is has invaded, including North America.
Technical Abstract: The wheat curl mite (WCM), Aceria tosichella, is an important pest of wheat and other cereal crops that transmits wheat streak mosaic virus and several other plant viruses. WCM has long been considered a single polyphagous species, but recent studies in Poland revealed a complex of genetically distinct lineages with divergent host acceptance traits, ranging from highly polyphagous to host-specific. This diversity of WCM genotypes and host-acceptance phenotypes in Europe, the presumed native range of WCM, raises questions about the lineage identities of invasive WCM populations on other continents and their relationship to European lineages. The goals of this study were to examine the global presence of WCM and determine the relatedness of lineages established on different continents, on the basis of phylogenetic analyses of mitochondrial and nuclear DNA sequence data. Host-range bioassays on a highly polyphagous WCM lineage were performed to supplement existing data on its ability to colonize graminaceous and non-graminaceous hosts. Our results showed that invasive WCM populations in North and South America and Australia assorted with the only three known polyphagous and pestiferous WCM lineages ('MT-1', 'MT-7' and 'MT-8') from a total of eight currently described lineages. These results highlight the importance that the most polyphagous lineages were more successful colonizers and reflect a need for extensive surveys for WCM on both crops and wild grass species on invaded continents. The most invasive lineage ('MT-1') was shown to successfully colonize all 10 plant species tested in three families and has spread to five continents.