SGM Journals

Research explained · Plant virus transmission

Why can thrips carry tomato spotted wilt virus without spreading it?

Both groups of thrips in a lab study could pick up tomato spotted wilt virus as larvae and support its replication in the gut. Only the western flower thrips passed it on as adults. Researchers found the virus in their salivary glands and did not detect it there in the tested onion thrips population. [1]

See original studies View the SGM research record

Where the virus was found

Larval midgut
The virus replicated in larvae of both populations, with less virus accumulating in the tested onion thrips.
Both groups could support replication in the gut, although their ability to transmit later differed. [1]
Tissues beyond the gut
In western flower thrips, researchers detected virus first in the gut lining, then in gut muscle, ligaments and salivary glands.
The virus reached tissues involved in delivering it to another plant. [1]
Adult transmission
The tested western flower thrips transmitted efficiently. Adults of the tested onion thrips population did not.
These results compare two specific populations under the same study conditions. [1]

What makes an insect a competent vector?

Vector competence is an insect’s ability to acquire and transmit a particular pathogen. A test can detect a virus inside an insect before anyone knows whether it can spread. In this study, the researchers tested the adults separately for transmission. [1]

Does reaching the salivary glands explain everything?

The adult transmission results tracked whether researchers could find the virus in the salivary glands. The two groups also differed in how much virus accumulated and how far it spread from the gut. The experiment did not isolate a single cause for the transmission difference. [1]

Can other onion thrips transmit it?

Yes. A later study paired several onion thrips lines with different virus isolates and recorded successful transmission in some pairings. The amount of virus detected did not consistently predict which pairings transmitted it. [1][2]

Original research

  1. Nagata et al. (2002), Journal of General Virology. Factors determining vector competence and specificity for transmission of Tomato spotted wilt virus. Primary tissue-localization and transmission comparison of two thrips populations.
  2. Linak et al. (2020), Scientific Reports. Relationships of virus titers and transmission rates among sympatric and allopatric virus isolates and thrips vectors support local adaptation. Independent measurements across multiple onion-thrips and virus-isolate pairings.