Abstract
Soybean is the most important leguminous crop in Brazil and the nitrogen required for plant growth is supplied byBradyrhizobium bacteria through the symbiotic relation established by the inoculation process. Since 1992, two new strains, CPAC 7 and CPAC 15, which have been shown to increase yields in several field experiments, have been recommended in Brazilian commercial inoculants. CPAC 15 is a natural variant of theB. elkanii SEMIA 566 strain, and was isolated after several years of adaptation to a Brazilian Cerrado soil, while CPAC 7 is a variant ofB. japonicum strain CB 1809, selected under laboratory conditions for higher nodulation and yield. The comparison between parental and variant strains, under greenhouse conditions, showed that both CPAC 15 and CPAC 7 increased N2 fixation rates in relation to the parental strains. The better performance of CPAC 15 was related to an increase in nodule efficiency (mg N2 fixed mg-1 nodule) while with CPAC 7 the higher N2 fixation rates were due to increased nodulation. Both CPAC 15 and CPAC 7 increased nodule occupancy, when co-inoculated at a ratio of 1:1 withB. elkanii 29w, in relation to their parental strains. Variant strains also differed from parental in their ability to increase numbers of root hairs (Hai phenotype) either when inoculated onto plants, or when supernatants of bacteria exposed to seed exudates were used as inoculants. This results lead to the hypothesis that a modification in some of the “common” nodulation genes had occurred. However, the increase in Hai phenotype with CPAC 7 was dependent on the soybean cultivar, indicating a possible alteration in some genotypic specific nodulation gene. Apparently, there were no differences in Nod metabolites produced by strains CPAC 15 and SEMIA 566, but a more detailed chemical analysis would be required to rule out subtle differences. On the contrary, significant differences were found between CPAC 7 and the parental strain CP 1809, in the profile of Nod metabolites. Consequently, it may be possible that diffusable molecules, responsible for Hai phenotype, would be related to nodulation ability, competiviveness, and N2 fixation, resulting in the higher yields that have been associated with CPAC 7 and CPAC 15. For the CPAC 7 strain, the increase in Hai phenotype could be atributed to the differences found in the Nod molecules. Consequently, a high degree of physiological and genetic variability can result from the adaptation of rhizobial strains to the soil. Also, this variability can be found under laboratory conditions, when searching single colonies with specific properties. ei]Section editor: R O D Dixon
Similar content being viewed by others
References
Canter Cremers H C J, vanBrussel A A N, Plazinski J and Rolfe B G 1986 Sym plasmid and chromosomal gene products ofRhizobium trifolii elicit developmental responses on various legume roots. J. Plant Physiol. 122, 25–40.
Carlson R W, Sanjuan J, Bhat U R, Glushka J, Spaink H P Wijfjes A H M, vanBrussel A A N, Stokkermans T J W, Peters N K and Stacey G 1993 The structures and biological activities of the lipo-oligosaccharide nodulation signals produced by type I and type II strains ofBradyrhizobium japonicum. Proc. Natl. Acad. Sci. USA 268, 18372–18381.
Cattelan A J and Hungria M 1994 Nitrogen nutrition and inoculation.In Tropical Soybean-Improvement and Production. Ed. FAO. pp 201–215. FAO, Rome.
Faucher C, Camut S, Dénarié J and Truchet G 1989 ThenodH andnodQ host range genes ofRhizobium meliloti behave as avirulence genes inR. leguminosarum bv.viciae and determine changes in the production of plant-specific extracellular signals. Mol. Plant-Microb. Interact. 2, 291–300.
Faucher C, Maillet F, Vasse J, Rosenberg C, vanBrussel A N N Truchet G and Dénarié J 1988Rhizobium meliloti host rangenodH determines production of an alfalfa-specific extracellular signal. J. Bacteriol. 170, 5489–5499.
Feije F and Anger V 1972 Spot tests in inorganic analyses. Anal. Chem. Acta 149, 363–367.
Fuhrmann J 1990 Symbiotic effectiveness of indigenous soybean bradyrhizobia as related to serological morphological, rhizobiotoxine and hydrogenase phenotypes. Appl. Environ. Microbiol. 56, 224–229.
Hanus FJ, Albrecht S L, Zablotowicz R M, Emerich D W, Russell S A and Evans H J 1981 Yield and N content of soybean seed as influencedby Rhizobium japonicum inoculants possessing the hydrogenase characteristic. Crop Sci. 73, 368–372.
Hungria M, Joseph C M and Phillips D A 1991a Anthocyanidins and flavonols, majornod gene inducers from seeds of a black-seeded common bean (Phaseolus vulgaris L.). Plant Physiol. 97, 751–758.
Hungria M, Joseph C M and Phillips D A 1991bRhizobium nod gene inducers exuded naturally from roots of common bean (Phaseolus vulgaris L.). Plant Physiol. 97, 759–764.
Hungria M, Neves M C P and Döbereiner J 1989 Relative efficiency, ureide transport and harvest index in soybeans inoculated with isogenic HUP mutants ofBradyrhizobium japonicum. Biol. Fert. Soils 7, 325–329.
Hungria M, Vargas M A T, Suhet A R and Peres J R R 1994 Fixação biológica do nitrogênio em soja.In Microganismos de Importância Agricola. Eds. R SAraujo and MHungria. pp 9–89. EMBRAPA-SPI, Brasília, Brazil.
Kosslak R M, Bookland R, Barkei J, Paaren H E and Appelbaum E R 1987 Induction ofBradyrhizobium japonicum commonnod genes by isoflavone isolated fromGlycine max. Proc. Natl. Acad. Sci. USA 84, 7428–7432.
Lerouge P, Roche P H, Faucher C, Maillet F, Truchet G, Promé J C and Dénarié J 1990 Symbiotic host-specificity ofRhizobium meliloti is determined by a sulphated and acylated glucosamine oligosaccharide signal. Nature 344, 781–784.
Liu R, Tran V M and Schimidt E L 1989 Nodulating competitiveness of a nonmotileTn7 mutant ofBradyrhizobium japonicum in non-sterile soil. Appl. Environ. Microbiol. 55, 1895–1900.
Neves M C P and Hungria M 1987 The physiology of nitrogen fixation in tropical grain legumes. CRC Crit. Rev. Plant Sci. 6, 267–321.
Nishi C Y M, Boddey L H, Vargas M A T and Hungria M 1996 Morphological, physiological and genetic characterization of two newBradyrhizobium strains recently-recommended in Brazilian commercial inoculants for soybean. Symbiosis 20, 147–162.
Peres J R R, Vargas M A T and Suhet A R 1984 Variabilidade de eficiência em fixar nitrogênio entre isolados de uma mesma estirpe deRhizobium japonicum. Rev. Bras. Cienc. Solo 8, 193–196.
Peters N K, Frost J W and Long S R 1986 A plant flavone, luteolin, induces expression ofRhizobium meliloti nodulation genes. Science 233, 977–980.
Sadowsky M J, Cregan P B, Gottfert M, Sharma A, Gerhold D, Rodrigues-Quinones F, Keyser H H, Hennecke H and Stacey G 1991 TheBradyrhizobium japonicum nolA gene and its involvement in the genotype-specific nodulation of soybeans. Proc. Natl. Acad. Sci. USA 88, 637–641.
Sanjuan J, Carlson R W, Spaink H P, Bhat U R, Barbour W M, Glushka J and Stacey G A 1992 A 2-O-methylfucose moiety is present in the lipo-oligosaccharide nodulation signal ofBradyrhizobium japonicum. Proc. Natl. Acad. Sci. USA 89, 8789–8793.
Smith G B and WollumII A G 1989 Nodulation ofGlycine max by sixBradyrhizobium japonicum strains with different competitive abilities. Appl. Environ. Microbiol. 55, 1957–1962.
Somasegaran P and Hoben H J 1985 Methods in Legume-Rhizobium Technology. Niftal, Hawaii, USA. 367 p.
Spaink H, Aaarts A, Stacey G, Bloemberg G, Lugtenberg B J and Kennedy E P 1992 Detection and separation ofRhizobium andBradyrhizobium Nod metabolites using thin layer chromatography. Mol. Plant-Microbe Interact. 6, 72–80.
Sprent J I and Sprent P 1990 nitrogen Fixing Organisms: Pure and Applied Aspects. Chapman and Hall, New York, USA. 256 p.
Streeter J G, Salminen S O, Whitmoyer R E and Carlson R W 1992 Formation of novel polysaccharides byBradyrhizobium japonicum bacteroids in soybean nodules. Appl. Environ. Microbiol. 58, 607–613.
VanBrussel A A N, Zaat S A J, Canter Cremers H C J Wijffelman C A, Pees E, Tak T and Lugtenberg B J J 1986 Role of plant root exudate and Sym plasmid-localized nodulation genes in the synthesis byRhizobium leguminosarum ofTsr factor which causes thick and short roots on common vetch. J. Bacteriol. 165, 517–522.
Vargas M A T, Mendes I D C, Suhet A R and Peres J R R 1992, Duas 084 novas estirpes de rizóbio para a inoculação da soja. (Comunicado Técnico 62). EMBRAPA-CPAC, Planaltina Brazil. 3 p.
Vargas M A T, Peres J R R and Suhet A R 1982 Adubação nitrogenada, inoculação e épocas de calagem para a soja em um solo sob Cerrado. Pesq. Agropec. Bras. 17, 1127–1132.
Vasse J M and Truchet G L 1984 TheRhizobium-legume symbiosis: Observation of root infection by bright-field microscopy after staining with methylene blue. Planta 161, 487–489.
Vincent J M 1970 Manual for the Practical Study of Root Nodule Bacteria. IBP Handbook 15. Blackwell Scientific Publications, Oxford, UK, 164 p.
Vincet J M 1980 Factors controlling the legume-Rhizobium symbiosis.In Nitrogen Fixation. Eds. W ENewton and W HOrme-Johnson. pp 103–129. Univ. Park, Baltimore, UK.
Viteri S E and Schmidt E L 1987 Ecology of indigenous soil rhizobia: Response ofBradyrhizobium japonicum to readily available substrate. Appl. Environ. Microbiol. 53 1872–1875.
Zaat S A J, vanBrussel A A N, Tak T, Pees E and Lugtenberg B J J 1987 Flavonoids induceRhizobium leguminosarum to producenodDABC gene-related factors that cause thick short roors and root hair responses on common vetch. J. Bacteriol. 169, 3388–3391.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Hungria, M., Nishi, C.Y.M., Cohn, J. et al. Comparison between parental and variant soybeanBradyrhizobium strains with regard to the production of lipo-chitin nodulation signals, early stages of root infection, nodule occupancy, and N2 fixation rates. Plant Soil 186, 331–341 (1996). https://doi.org/10.1007/BF02415528
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF02415528