Physiological and biochemical characteristics of a fast-growing strain of lupin rhizobia isolated from the sonoran desert

An effective, fast-growing strain of lupin rhizobia was isolated from a species of Lupinus native to the Sonoran Desert near San Felipe, Baja, Mexico (generation time, 3.6 h). Bacteria isolated from the roots of lupins are normally slow growing, however. Lupin 43 was fast-growing, possessed multiple flagella and produced acid in a denned medium. In comparison to a slow-growing lupin strain. Nitragin 96AII; Lupin 43 had a low intrinsic resistance to antibiotics and was able to utilize a wider range of C and N-sources. When compared to a fast-growing strain of Rhizobium meliloti, also isolated from the Sonoran Desert, Lupin 43 had a slightly faster growth rate, was less resistant to antibiotics and produced alkaline end products when asparagine was supplied as N-source. Based on these characteristics. Lupin 43 was more similar to other fast-growing rhizobia than the slow growing lupin rhizobia.