Sym plasmid transfer to various symbiotic mutants of Rhizobium trifolii, R. leguminosarum, and R. meliloti

Djordjevic, Michael A.; Zurkowski, W; Shine, John; Rolfe, Barry G.

doi:10.1128/jb.156.3.1035-1045.1983

Cited by 73 publications

(28 citation statements)

References 20 publications

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“…trifolii Ti and the self-mobilizable R. leguminosarum bv. viciae Sym plasmid pJB5JI, and its transfer to other Rhizobium strains, have previously been outlined by Djordjevic et al (9). Nodulation of T. subterraneum in agar culture at low pH.…”

Section: Methodsmentioning

confidence: 88%

Construction of an Acid-Tolerant Rhizobium leguminosarum Biovar Trifolii Strain with Enhanced Capacity for Nitrogen Fixation

Chen

Richardson

Gärtner

et al. 1991

Appl Environ Microbiol

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Strain ANU1173 is an acid-tolerant Rhizobium leguminosarum biovar trifolii strain that is able to nodulate subterranean clover plants growing in agar culture at pH 4.4. At pH 6.5, its symbiotic effectiveness in association with Trifolium subterraneum cv. Mt. Barker was 80% relative to that of strain ANU794, a Smr derivative of the commercial inoculant R. kguminosarum bv. trifolii TAl. Strain ANU1173 contained four indigenous megaplasmids, the smallest of these being the symbiotic (Sym) plasmid. The critical pH requirement for growth of strain ANU1173 in laboratory media was shown not to be associated with this plasmid. When the Sym plasmid of strain ANU1173(pSym-1173) was mobilized into a Nod-strain of R. leguminosarum bv. viciae, the plasmid conferred to the transconjugant a level of symbiotic effectiveness in association with T. subterraneum that was similar to that observed with ANU1173. The symbiotic effectiveness of strain ANU1173 was improved by first curing pSym-1173 (generating strain ANU1184) and replacing it with another R. leguminosarum bv. trifolii Sym plasmid, pBRlAN. Subterranean clover plants inoculated with strain ANU1184 (pBR1AN) exhibited a 35 or 53% increase in acetylene reduction activity and a 20 or 17% increase in dry weight when grown at pH 6.5 and pH 4.4, respectively, compared with plants inoculated with strain ANU1173 and grown under the same pH conditions. It was further shown that pBRlAN was stably maintained in strain ANU1184 under free-living and symbiotic conditions. These results indicate that it is possible to construct an acid-tolerant strain of R. leguminosarum bv. trifolii with an enhanced capacity for nitrogen fixation.

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Section: Methodsmentioning

confidence: 88%

Construction of an Acid-Tolerant Rhizobium leguminosarum Biovar Trifolii Strain with Enhanced Capacity for Nitrogen Fixation

Chen

Richardson

Gärtner

et al. 1991

Appl Environ Microbiol

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“…Ainsi, les genes du Rhizobium impliquCs dans le developpement de la symbiose sont classifies en genes N O D (genes de nodulation) et genes FIX (genes de fixation de l'azote) qui incluent l'opkron NIF codant la Nitrogenase. Dans la symbiose a rhizobium a croissance rapide, les genes intervenant dans la reconnaissance de l'h6te sont localises dans de gros plasmides ( DJORDJEVIC et al 1983).…”

Section: Processus D'infectionunclassified

Comparaison du mode d'infection et du développement des nodosités racinaires et caulinaires chez quelques légumineuses des genres Sesbania et Aeschynomene

Ramaroson

Schramm

1989

J. Basic Microbiol.

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Comparaison du mode d'infection et du developpement des nodosites racinaires et caulinaires chez quelques legumineuses des genres Sesbania et Aeschynomene ESTHEL RAMAROSON' et MICHAEL SCHRAMMSesbania rostrata and fifteen species of Aeschjinomene are tropical legumes which can grow in flooded soils because they have both root and stem nodulation. They are of particular agronomic interest because of their potential for maintaining soil fertility. Three genera of rhizobia are associated symbiotically with these stem nodulating legumes: Rhizobium infects S. rostrata and some Aeschynomene species; Azorhizobium is specific to S. rostrafa and can live outside the plant; Brudyrhizobium infects only Aeschynomene species.In S . rostrata root infection occurs by root hair curling, whereas stem nodulation is achieved by entry of bacteria at the site of emerging adventitious rootlets. Many studies have reported that infection by thread formation is observed on both roots and stems of S. rostrata.In S. rostrata, the process of root infection has been shown to follow several stages: recognition and attachment of rhizobia to the root surfaces induction of root hair curling; formation of infection threads that guide bacteria to the adjacent cortical root cells; release of bacteria into the cytoplasm of host cells where they are enveloped by host plasmalemm.Stem infection of S . rostrata has been shown to have four stages: rhizobial penetration in degenerated cortical cells through cracks at the site of emerging rootlcts; Rhizobium proliferates in the intercellular cavities and initiates meristematic nodules; infection threads form in the intercellular cavities and in the host cells; rhizobia are intercellularly released by an endmytotic process.Most of the stem nodulated Aeschynomene spp. have displayed the same process of root infection as S. rostrata. A.indica is an exception in that it appears that the path of infection is constituted by the rupture of tissue restricted to the place of rootlet emergence. No infection thread formation is observed in A . indicu.The unique characteristic of all stem-nodulating legumes is the presence of pre-determined nodulation sites on their stems. In Aeschynomene, the process of stem infection does not involve formation of infection threads but is effected by penetration of Rhizobinwn through cracks which surround the root primordia. This penetration is followed by hydrolysis of host epidermic cell walls causing the release of the bacteria into cell cytoplasm.Stem-nodulating legumes infection depends on both ecological and intrinsic legumes factors. It is important to note that the nitrogen fixation of S. rostratu, A . ufraspera, and A . scahra was not inhibited by mineral nitrogen.The role of leaghemoglobin in the regulation and protection of nitrogenase activity is well establishcd. Recently, it was suggested that supcroxide dismutase, which is present at high levels in bactcroides isolated from root and stem nodules of a few stem-nodulating Icgumes, would be another regulator and protector ...

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“…The mechanisrn of host specificity is not well understood at the molecular level. Genes controlling host specificity of nodulation reside on symbiotic plasmids in fast-growing rhizobia such as R. meliloti, R. trifolii, and R. leguminosarum (3,4,7,12,13,15). Host specificity genes have not been identified or associated with plasmids in slow-growing rhizobia such as R. japonicum.…”

mentioning

confidence: 99%

“…The observation that selection for pSyml91 in USDA 257 resulted in recombination with pSym257 suggests that pSyml91 is unable to replicate or segregate properly in USDA 257, possibly owing to incompatibility between these two plasmids. Recombination between Sym plasmids from R. leguminosarum and R. trifolii has also been attributed to incompatibility between the plasmids (5,7). pSyml91 is apparently compatible with the resident plasmids and megaplasmids of the other recipient strains.…”

mentioning

confidence: 99%

Expression of symbiotic genes of Rhizobium japonicum USDA 191 in other rhizobia

Appelbaum¹,

McLoughlin²,

O’Connell³

et al. 1985

J Bacteriol

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Sym plasmid transfer to various symbiotic mutants of Rhizobium trifolii, R. leguminosarum, and R. meliloti

Cited by 73 publications

References 20 publications

Construction of an Acid-Tolerant Rhizobium leguminosarum Biovar Trifolii Strain with Enhanced Capacity for Nitrogen Fixation

Construction of an Acid-Tolerant Rhizobium leguminosarum Biovar Trifolii Strain with Enhanced Capacity for Nitrogen Fixation

Comparaison du mode d'infection et du développement des nodosités racinaires et caulinaires chez quelques légumineuses des genres Sesbania et Aeschynomene

Expression of symbiotic genes of Rhizobium japonicum USDA 191 in other rhizobia

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