Hello,
Is it possible to request that the “Ralstonia nicotianae” taxon is reverted back to “Ralstonia pseudosolanacearum” on GTDB?
We ran a thorough ANI analysis for a data-driven critique of the paper that proposed this species separation. Our argument is here:
https://apsjournals.apsnet.org/doi/full/10.1094/PHYTOFR-06-23-0071-LE
Dear Tiffany,
Thank you for your request and I apologize for the delay in responding!
We are sorry to hear that the proposal of the new species has caused confusion…
We discussed the case of R. nicotianae within our team and considered possible actions we could take. However, we regret to inform you that we have concluded that this change (i.e., species union) cannot be implemented in our upcoming release for several reasons.
The first reason is that we rely on primary sources, such as NCBI and LPSN, for nomenclature and type strain information. At present, there have been no updates from their side to reflect R. nicotianae as a later synonym of R. pseudosolanacearum or to consider the former name as illegitimate or rejected.
The second reason is that we adhere to an operational definition of species as described here. Briefly, we aim to preserve existing species names anchored to type strains wherever possible. Therefore, our ANI thresholds are more permissive (please read more here). This approach has allowed us to maintain nomenclatural stability while relying on the gold standards of prokaryotic systematics. However, as there is no one-size-fits-all solution for defining prokaryotic species (see another recent example of outliers), our primary focus remains consistency. While we plan to re-evaluate this approach in the future, such changes will inevitably lead to the loss of other species names, making this a non-trivial decision.
The third reason is that we cannot make exceptions to the currently applied rules without strong justification. If the Judicial Commission of the ICSP issues an Opinion rejecting the name R. nicotianae, and LPSN and NCBI update their corresponding records, this can have a stronger case to implement the change. If we re-evaluate the current ANI-based definitions for all GTDB species, this may also result in desirable changes.
We truly wish we could assist further, and we hope you understand the need to approach such decisions carefully. If you need any further assistance or advice, please don’t hesitate to reach out.
Thank you!
Best wishes,
On behalf of the GTDB team,
Masha