Ardley et al. have recently proposed three novel  Microvirga species, namely: Microvirga lupini (Lut6T = LMG26460T, = HAMBI 3236) Microvirga lotononidis (WSM3557T = LMG26455T, = HAMBI 3237) and Microvirga zambiensis (WSM3693T = LMG26454T, = HAMBI 3238), which correspond to nitrogen-fixing rhizobia. Read more about this interesting finding in their paper: "Ardley JK, Parker MA, De Meyer SE, Trengove RD, O'Hara GW, Reeve WG, Yates RJ, Dilworth MJ, Willems A, Howieson JG. Microvirga lupini sp. nov., Microvirga lotononidis sp. nov., and Microvirga zambiensis sp. nov. are Alphaproteobacterial root nodule bacteria that specifically nodulate and fix nitrogen with geographically and taxonomically separate legume hosts. Int J Syst Evol Microbiol. 2011 Dec 23. [Epub ahead of print]". PubMed PMID: 22199210 . Microvirga classification: Class -> Alphaproteobacteria; Order -> Rhizobiales; Family -> Methylobacteriaceae