The ICTV's recommendation for how to write virus, species and other taxa names. (Updated September 16, 2020)
The ICTV Study Group recommends using TBRFV as the abbreviation for Tomato brown rugose fruit virus (see https://talk.ictvonline.org/ictv-reports/ictv_online_report/positive-sense-rna-viruses/w/virgaviridae/672/genus-tobamovirus). But keep in mind that this is just a recommendation. The ICTV does not officially endorse virus name abbreviations.