A rapid method for the isolation and identification of Rhizobium from root nodules

We developed a rapid, inexpensive method for isolating and identifying Rhizobium leguminosarum by. phaseoli strains from bean root nodules. The method can be used for other small or medium-sized nodules such as those of clover, alfalfa and peas. With this method, one person can process 115 nodules/h. Using a simple apparatus made of plexiglass and machine bolts, we simultaneously crushed 24 surface-sterilized nodules and then transferred the crushed nodule suspension to multiple plates containing various antibiotics or a dye. This versatile and broadly applicable method complements previously described techniques, which are effective only for large root nodules such as those of soybean.