Mini transposon vector mediated foreign gene expression in <i>Mesorhizobium huakuii</i> subsp. <i>rengei</i>

Abstract

Among the transposable elements, mini-Tn5 transposon vector has proven to be of greater utility for insertion mutagenesis of variety of Gram negative bacteria. The mini-Tn5 vector containing promoter less <i>egfp </i>gene and gentamycin resistant gene was used for the present study. The transposon vector was introduced to <i>M. huakuii </i>from E. coli S17 by conjugation. The conjugants were screened for stable expression of <i>egfp </i>both in free-living and in nodules of <i>Astragalus sinicus. </i>The result showed that the conjugant #3 showed stable expression of green fluorescent both in free-living and bacteroid stage. The visualization of <i>sym </i>plasmid of wild strain and conjugants showed that conjugant #3 had a fragmentation of large sized plasmid into two but without affecting the nodulating ability. These results clearly indicated that mini-Tn5 vectors (Transposon vectors) the best alternate tools for plasmid vectors for integration of foreign genes in chromosomal DNA or symbiotic plasmid and expression, both in free-living and bacteroid stage of <i>Rhizobium.</i>