Location: Foreign Disease-Weed Science Research
Title: Rathayibacter toxicus: development of a gene knock-out system and interactions with Anguina and Afrina nematodes native to the U.S.Author
|
Submitted to: Meeting Abstract
Publication Type: Abstract Only Publication Acceptance Date: 3/25/2024 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Rathayibacter toxicus is a gram-positive bacterium and USDA-listed Select Agent plant pathogen that is the causative agent of annual ryegrass toxicity, a toxicosis that has caused devastating losses to the Australian livestock industry. R. toxicus exhibits a complex life cycle, using the seed gall nematodes Anguina funesta and A. paludicola as a physical vector, attaching to the cuticle and being carried up to the developing seed head of annual ryegrass (Lolium rigidum). Infected grass seed contains both nematode and bacterial colonized galls; bacterial galls may contain a highly toxic, tunicamycin-like toxin. We have identified the probable tunicamycin biosynthetic cluster (TGC) based on homology to tunicamycin biosynthetic clusters in other related bacteria[1]. We are developing a gene knock-out system to disrupt the TGC and conclusively demonstrate that it is responsible for toxin biosynthesis. It is not known whether R. toxicus may be capable of interacting with and therefore potentially be vectored by other Anguinid nematodes, including species present in the U.S. To test this possibility, nematode agglutination assays are being performed between R. toxicus and Afrina sporoboliae, Anguina tritici, and Anguina agrostis. If R. toxicus adheres to the nematode cuticle, the nematodes will agglutinate, or clump, indicating it is likely that nematode could serve as a vector of R. toxicus. This type of information will inform risk assessment should R. toxicus ever be identified outside of Australia. [1] Sechler, et. al, 2017. PloS One 12(8): e0183005. |
