Lipo-chito oligosaccharides (LCOs) are produced by culturing rhizobacteria cells in or on a culture medium comprising at least one of: jasmonic acid or a derivative thereof; linoleic acid or a derivative thereof; or linolenic acid or a derivative thereof. Preferably, the rhizobacteria cells are Bradyrhizobium japonicum cells having the identifying characteristics of B. japonicum strain USDA 3. Preferably, the derivative of jasmonic acid is an ester thereof, preferably methyl jasmonate. Also provided are methods for improving LCO production at low temperatures, particularly temperatures below 25.degree. C.