(Iron regulation of gene expression in the Bradyrhizobium japonicum/soybean symbiosis)

Technical Report · Wed Jan 01 04:00:00 EST 1992

DOI:https://doi.org/10.2172/5312051· OSTI ID:5312051

Guerinot, M L

We wish to address the question of whether iron plays a regulatory role in the Bradyrhizobium japonicum/soybeam symbiosis. Iron may be an important regulatory signal in planta as the bacteria must acquire iron from their plant hosts and iron-containing proteins figure prominently in all nitrogen-fixing symbioses. For example, the bacterial partner is believed to synthesize the heme moiety of leghemoglobin, which may represent as much as 25--30% of the total soluble protein in an infected plant cell. For this reason, we have focused our attention on the regulation by iron of the first step in the bacterial heme biosynthetic pathway. The enzyme which catalyzes this step, 5-aminolevulinic acid synthase, is encoded by the hemA gene which we had previously cloned and sequenced. Specific objectives include: to define the cis-acting sequences which confer iron regulation on the B. japonicum hemA gene; to identify trans-acting factors which regulate the expression of hemA by iron; to identify new loci which are transcriptionally responsive to changes in iron availability; and to examine the effects of mutations in various known regulatory genes for their effect on the expression of hemA.

• Research Organization: Dartmouth Coll., Hanover, NH (United States). Dept. of Biological Sciences
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: FG02-91ER20032
• OSTI ID: 5312051
• Report Number(s): DOE/ER/20032-1; ON: DE92013715
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
550400 -- Genetics
550700 -- Microbiology
553000 -- Agriculture & Food Technology
59 BASIC BIOLOGICAL SCIENCES
60 APPLIED LIFE SCIENCES
BACTERIA
BIOCHEMISTRY
BIOSYNTHESIS
CHEMISTRY
DOCUMENT TYPES
ELEMENTS
FOOD
GENES
IRON
METALS
MICROORGANISMS
MUTATIONS
ORGANIC COMPOUNDS
PLANTS
PROGRESS REPORT
PROTEINS
SOYBEANS
SYMBIOSIS
SYNTHESIS
TRANSITION ELEMENTS
VEGETABLES