THE CONSTRUCTION, DETECTION AND USE OF BIOLUMINESCENT RHIZOBIUM-LEGUMINOSARUM BIOVAR TRIFOLII STRAINS

Citation
A. Cresswell et al., THE CONSTRUCTION, DETECTION AND USE OF BIOLUMINESCENT RHIZOBIUM-LEGUMINOSARUM BIOVAR TRIFOLII STRAINS, Journal of Applied Bacteriology, 77(6), 1994, pp. 656-665
Citations number
41
Categorie Soggetti
Microbiology,"Biothechnology & Applied Migrobiology
ISSN journal
00218847
Volume
77
Issue
6
Year of publication
1994
Pages
656 - 665
Database
ISI
SICI code
0021-8847(1994)77:6<656:TCDAUO>2.0.ZU;2-M
Abstract
The gene encoding the firefly luciferase enzyme (luc) was introduced t o Rhizobium leguminosarum biovar trifolii strains with a view to using the resulting bioluminescent strains to study the survival of genetic ally-engineered rhizobia in soil microcosms. The genetically-engineere d micro-organisms (GEMs) behaved similarly to their parent strains wit h respect to growth rate in laboratory media and in their symbiotic pe rformance with their host plants. No gene transfer could be detected i n laboratory mating experiments. When inoculated onto a non-sterile so il the population of the GEM declined sharply from an initial cell den sity of 2 x 10(7) g(-1) soil to approach a stable cell density of appr oximately 3 x 10(2) g(-1) after 150 d. Direct photography of biolumine scent rhizobia enabled the detection of colonies as small as 0.1 mm in diameter without the need for transferring colonies onto filter paper . When a Rhizobium strain carrying the luc marker on a plasmid was use d as inoculant it was possible to visualize differences in colonizatio n of the rhizosphere of white clover and ryegrass by contact print and colour transparency films. The photographic detection methods describ ed here demonstrate the possibilities of using bioluminescent rhizobia for assessing their survival in soil, and for looking at rhizosphere populations which may be an important site for potential gene transfer .