The Xanthomonadaceae are a family of Proteobacteria, given their own order.
References
^Anzai, et al.; Kim, H; Park, JY; Wakabayashi, H; Oyaizu, H (2000, Jul). "Phylogenetic affiliation of the pseudomonads based on 16S rRNA sequence". Int J Syst Evol Microbiol50 (4): 1563–89. doi:10.1099/00207713-50-4-1563. PMID10939664.