| Abstract: | A chromosomal gene, required for nodule development on Phaseolus bean, was characterized from Rhizobium etli strain TAL182. MLC640 is a Tn5 insertion mutant of TAL182 which shows decreased motility in soft TY agar and is defective in nodule development. The site of Tn5 insertion in MLC640 mapped to a 3.6-kb EcoRI chromosomal fragment. The 3.6-kb fragment was subcloned from the cosmid pUHR80 which complemented MLC640. Further subcloning and site-directed Tn5 mutagenesis localized the gene for nodule development to a 1.7-kb region within the 3.6-kb EcoRI fragment. Southern hybridization using the 3.6-kb EcoRI fragment as the probe against genomic DNA of several Rhizobium spp. indicated that this gene is conserved in different rhizobia.The authors are with the Department of Plant Molecular Physiology, University of Hawaii, 3050 Maile Way, Gimore 402, Honolulu, Hawaii 96822. USA; |
