Nodulation gene factors and plant response in the Rhizobium-legume symbiosis. [Nodulation]
Our original application aimed to identify genes outside the common nod region involved in nodulation and host range of alfalfa. This has been revised by adding other studies on nodulation gene action and removing molecular studies of gene action. Our restated goals and progress are as follows. An early goal was identification and characterization of additional nodulation genes. By means of transposon mutagenesis, mapping and marker exchange we have established 87 independent mutations in a 20kb area represented by plasmid pRmJT5. We discovered four new genes: nodP, nodD3, syrA and syrM. The sequence, start site and protein product for nodFe, nodG, and nodH were also identified. Regulation of nod FEGH was studied. nod FEGH can be induced by luteolin in the presence of noodle; nodD1; noD3 and syrM, a symbiotic regulator gene also increase transcription of nod FEGH. syrA will interact with syrM; syrM also regulates exopolysaccharide genes and is believed to be a master regulator. As part of these studies, an in vitro transcription/translation system for Rhizobium was developed. Adjacent to nodP we discussed nodQ, nodPQ occurrs in two highly consumed copies. nodQ appears by sequence analysis to be similar to initiation and elongation factors, with the highest homology in the GDP binding domain. We have also investigated the nod strain, WL131. WL131 has an insertion, ISRm3, interrupting nodG, and a nonsase mutation in nodH, nodH is responsible for the lack of nodulation. We are currently investigating supernatant factors, host range effects C by spot inoculation, glucaronidase fusion proteins, and are developing, a single root hair inoculation protocol. 7 refs., 6 figs., 1 tab.
- Research Organization:
- Stanford Univ., CA (USA). Dept. of Biological Sciences
- Sponsoring Organization:
- DOE/ER
- DOE Contract Number:
- AT03-82ER12084
- OSTI ID:
- 6150676
- Report Number(s):
- DOE/ER/12084-T1; ON: DE91008216
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
60 APPLIED LIFE SCIENCES
ALFALFA
GENE REGULATION
GENES
RHIZOBIUM
GENE MUTATIONS
TRANSPOSONS
MUTAGENESIS
DNA SEQUENCING
GENETIC MAPPING
INOCULATION
NITROGEN FIXATION
PLASMIDS
PROGRESS REPORT
ROOTS
SYMBIOSIS
TRANSCRIPTION
BACTERIA
CELL CONSTITUENTS
DOCUMENT TYPES
LEGUMINOSAE
MAGNOLIOPHYTA
MAGNOLIOPSIDA
MAPPING
MICROORGANISMS
MUTATIONS
PLANTS
STRUCTURAL CHEMICAL ANALYSIS
550400* - Genetics
550700 - Microbiology
553000 - Agriculture & Food Technology
550200 - Biochemistry