Mesorhizobium loti, formerly known as Rhizobium loti,[1] is a Gram negative species of bacteria found in the root nodules of many plant species.

[2] Its name is a reference to Lotus corniculatus, a flowering plant from which it was originally isolated.

The complete genome sequence of a strain of M. loti was determined in 2000.

[3] Unusually, M. loti has two Ku genes (mlr9624 and mlr9623) instead of the usual one in each bacterial species.

(Ku is involved in NHEJ repair.