Submitted to: Current Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/27/1997
Publication Date: N/A
Interpretive Summary: Nitrogen fixation is a process by which certain plants obtain the essential nutrient nitrogen. To obtain this nitrogen from the atmosphere, these leguminous plants maintain a relation with a bacteria called Brady rhizobium japonicum. These bacteria have long been known to have differences in chemically measurable characteristics such as their ability to grow on different media, and they have been classified by these differences into strains. Some of these strains are more efficient at obtaining nitrogen than others, and some are more environmentally tolerant than others. It was observed that bacteria could alter the plant tolerance of soybean to drought even when the bacteria were from the same strain but maintained in different laboratories. These bacteria were not distinguishable by classical methods. Therefore, a new genetic method was used to show that the bacteria not only were different in their association with soybean drought tolerance but also genetically different. This procedure has the possibility of both helping maintain more consistent cultures of bacteria and advancing greater understanding of drought tolerance in soybean.
Technical Abstract: The polymerase chain reaction with arbitrary primers (RAPD) discriminated between two separately maintained cultures of Bradyrhizobium japonicum USDA 110 differing in symbiotic performance under drought conditions. Since strain 110 is used in inoculum production, the use of RAPD to monitor inoculum cultures could help preserve their genetic composition and prevent the loss of important symbiotic properties. The use of RAPD could also be extended to other B. japonicum strains currently used in inoculum production.