Use of reporter gus-gene to study the colonization of rice roots by Azospirillum lipoferum

抄録

Azospirillum lip oferum gus-marked strain T 137-1 was constructed by Tn5 mutagenesis using E. coli S 17-1::mTn5SSgusA 20. The frequency of Tn5 mutagenesis was 2 x 10^<-7>. The transconjugant retained most of the properties of the wild strain as confirmed by biochemical tests and the reaction of the antiserum to A. lipoferum. The colonization ability of the gus-marked strain of Azospirillum was studied in growth pouches in a greenhouse at 5, 10, 20 and 30 days after inoculation (DAI). At 5 DAI, Azospirillum strains abundantly colonized the root surface. At 20 and 30 DAI, Azospirillum strains were still observed on young lateral roots and root hairs but the attachment sites were sparse and highly variable between the replicates Abbreviation: DAI-days after inoculation, ARA-acetylene reduction activity.