Abstract
The glyoxylate cycle is an anaplerotic pathway of the tricarboxylic acid cycle that allows bacteria to grow using acetate, fatty acids, or poly-β-hydroxybutyrate (PHB). In Sinorhizobium meliloti, activities of the glyoxylate cycle enzymes isocitrate lyase (AceA) and malate synthase (GlcB) are present during growth on these kinds of carbon sources, but a study of the importance of these enzymes in utilizing these carbon compounds under starvation conditions has not been done. We therefore evaluated the role of AceA and GlcB in the utilization of PHB by determining the PHB degradative and growth capacities of the S. meliloti wild type and aceA and glcB mutants under carbon starvation conditions in culture. We found that only the aceA gene product was essential for bacterial growth and PHB degradation under these conditions, presumably by generating succinate from the acetyl-CoA derived from PHB catabolism, thus allowing the cells to grow in the absence of an external carbon source.
This is a preview of subscription content, log in via an institution to check access.
References
Bergersen FJ, Turner GL (1990) Bacteroids from soybean root nodules: accumulation of poly-β-hydroxybutyrate during supply of malate and succinate in relation to N2 fixation in flow-chamber reactions. Proc R Soc Lond B 240:39–59
Bradford MM (1976) A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem 72:248–254
Cai GQ, Driscoll BT, Charles TC (2000) Requirement for the enzymes acetoacetyl coenzyme A synthetase and poly-3-hydroxybutyrate (PHB) synthase for growth of Sinorhizobium meliloti on PHB cycle intermediates. J Bacteriol 182:2113–2118
Cevallos MA, Encarnación S, Leija A, Mora Y, Mora J (1996) Genetic and physiological characterization of a Rhizobium etli mutant strain unable to synthesize poly-ß-hydroxybutyrate. J Bacteriol 178:1646–1654
Dunn MF (1998) Tricarboxylic acid cycle and anaplerotic enzymes in rhizobia. FEMS Microbiol Rev 22:105–123
Dunn MF, Ramírez-Trujillo JA, Hernández-Lucas I (2009) Major roles of isocitrate lyase and malate synthase in bacterial and fungal pathogenesis. Microbiology 155:3166–3175
Finan TM, Hartwieg E, LeMieux K, Bergman K, Walker GC, Signer ER (1984) General transduction in Rhizobium meliloti. J Bacteriol 159:120–124
Galibert F, Finan TM, Long SR et al (2001) The composite genome of the legume symbiont Sinorhizobium meliloti. Science 293:668–672
García-de los Santos A, Morales A, Baldomá L, Clark SR, Brom S, Yost CK, Hernández-Lucas I, Aguilar J, Hynes MF (2002) The glcB locus of Rhizobium leguminosarum VF39 encodes an arabinose-inducible malate synthase. Can J Microbiol 48:922–932
Geddes BA, Oresnik IJ (2014) Physiology, genetics, and biochemistry of carbon metabolism in the alphaproteobacterium Sinorhizobium meliloti. Can J Microbiol 60:491–507
Karunakaran R, Ramachandran VK, Seaman JC, East AK, Mouhsine B, Mauchline TH, Prell J, Skeffington A, Poole PS (2009) Transcriptomic analysis of Rhizobium leguminosarum biovar viciae in symbiosis with host plants Pisum sativum and Vicia cracca. J Bacteriol 191:4002–4014
Kornberg HL, Krebs HA (1957) Synthesis of cell constituents from C2-units by a modified tricarboxylic acid cycle. Nature 179:988–991
Kornberg HL, Madsen NB (1957) Synthesis of C4-dicarboxylic acids from acetate by a glyoxylate bypass of the tricarboxylic acid cycle. Biochim Biophys Acta 24:651–653
Law JH, Slepecky RA (1961) Assay of poly-ß-hydroxybutyric acid. J Bacteriol 82:33–36
Ramachandran VK, East AK, Karunakaran R, Downie JA, Poole PS (2011) Adaptation of Rhizobium leguminosarum to pea, alfalfa and sugar beet rhizospheres investigated by comparative transcriptomics. Genome Biol 12:R106
Ramírez-Trujillo JA, Encarnación S, Salazar E, García-de los Santos A, Dunn MF, Emerich DW, Calva E, Hernández-Lucas I (2007) Functional characterization of the Sinorhizobium meliloti acetate metabolism genes aceA, SMc00767 and glcB. J Bacteriol 189:5875–5884
Ratcliff WC, Denison RF (2010) Individual-level bet hedging in the bacterium Sinorhizobium meliloti. Curr Biol 20:1740–1744
Ratcliff WC, Denison RF (2011) Bacterial persistence and bet hedging in Sinorhizobium meliloti. Commun Integr Biol 4:98–100
Ratcliff WC, Kadam SV, Denison RF (2008) Poly-3-hydroxybutyrate (PHB) supports survival and reproduction in starving rhizobia. FEMS Microbiol Ecol 65:391–399
Tal S, Okon Y (1985) Production of the reserve material poly-3-hydroxybutyrate and its function in Azospirillum brasilense Cd. Can J Microbiol 31:608–613
Tombolini R, Nuti MP (1989) Poly(β-hydroxyalkanoate) biosynthesis and accumulation by different Rhizobium species. FEMS Microbiol Lett 60:299–304
Trainer MA, Charles TC (2006) The role of PHB metabolism in the symbiosis of rhizobia with legumes. Appl Microbiol Biotechnol 71:377–386
Trainer MA, Capstick D, Zachertowska A, Lam KN, Clark SR, Charles TC (2010) Identification and characterization of the intracellular poly-3-hydroxybutyrate depolymerase enzyme PhaZ of Sinorhizobium meliloti. BMC Microbiol 10:92
Wong PP, Evans HJ (1971) Poly-3-hydroxybutyrate utilization by soybean (Glycine max Merr.) nodules and assessment of its role in maintenance of nitrogenase activity. Plant Physiol 47:750–755
Acknowledgments
We would like to thank A. Vazquez, F. J. Santana, and M. Fernández-Mora for technical help.
Funding
This work was supported by grants from Dirección General de Asuntos del Personal Académico, DGAPA/UNAM (IN203215 to I.H.-L) and Consejo Nacional de Ciencia y Tecnología, CONACYT (89337, 127298 to I.H.-L).
Conflict of interest
The authors declare that they have no conflict of interest.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Ramírez-Trujillo, J.A., Dunn, M.F., Suárez-Rodríguez, R. et al. The Sinorhizobium meliloti glyoxylate cycle enzyme isocitrate lyase (AceA) is required for the utilization of poly-β-hydroxybutyrate during carbon starvation. Ann Microbiol 66, 921–924 (2016). https://doi.org/10.1007/s13213-015-1131-0
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s13213-015-1131-0