Alejandro García de los Santos

Genome Engineering Researcher

Associate Professor

Academic history

Biographical Sketch
Alejandro García de los Santos, PhD
Full Time Assistant Professor at the Center for Genomic Sciences, UNAM
Dr. Alejandro García de los Santos started his science training at the School of Sciences of the National Autonomous University of Mexico (UNAM) where he studied Biology. His work for his bachelor´s thesis introduced him to the microbial world that participates in cellulose degradation. After three years of work in this area, he moved to the Nitrogen Fixation Research Center (now Center for Genomic Sciences, UNAM) where he started to work on the organization of the bacterial culture collection of the Molecular Genetics department. He later on started to work as an assistant to Professor Susana Brom, who introduced him to the fascinating world of Rhizobium and the role of their large plasmids in genome plasticity and adaptation. Alejandro contributed to the systematic elimination of R. etli plasmids, which facilitated the identification of genes required for adaptation to different stresses. In his doctoral thesis, supervised by Susana Brom, Alejandro demonstrated that two plasmid-encoded genes are essential for the synthesis of lipopolysaccharides (lps), a cell surface component of gram-negative bacteria. His PhD thesis proposed that in the Rhizobium species, lps are required for interactions with plants.
Alejandro completed a postdoctoral stay with Michael Hynes, at the University of Calgary in Canada, searching for rhizobial genes that are turned on by sugars present in plant root exudates.
After that, Alejandro began to investigate the role of plasmid-encoded genes in the adaptation of Rhizobium to free life, their symbiosis with common bean plants, and their environmental stresses.
Alejandro and his colleagues found the uncommon location of housekeeping genes, essential for central metabolism, coded in plasmids. These findings contribute to support the definition of a new kind of replicon called chromid. The study of metabolic pathways in Rhizobia led him to find gaps in the pantothenate biosynthesis pathway in different Rhizobia. He has a project focused on reconstructing this metabolic pathway.
In the last five years, his research has been centered on mining the transportome of divalent metal ions (the repertory of proteins involved in metal uptake, intracellular trafficking and efflux processes) to understand how these bacteria maintain metal homeostasis. Although multiple genes encoding putative metal transport proteins are annotated in the genomes of Rhizobia, only few have been functionally characterized. Alejandro and his colleagues recently reported the characterization of three transporters that efflux nickel, cobalt, and manganese, belonging to the CDF superfamily (Cation diffusion facilitators), a porin-like protein involved in copper uptake, an In Silico analysis of occurrence, diversity and evolution of PIB-type ATPases in Rhizobia, and the main PIB-type ATPase of R. tropici which detoxify intracellular copper. The aim of the new projects is to analyze the global response of bacteria with high metal tolerance, using RNA-seq.



Telephone: (777) 3175867


2020López-Sámano, M., Beltrán, L.F.L.A., Sánchez-Thomas, R., Dávalos, A., Villaseñor, T., García-García, J.D., García-de los Santos, A.. (2020). "A novel way to synthesize pantothenate in bacteria involves ß-alanine synthase present in uracil degradation pathway". MICROBIOLOGYOPEN. 9(4):-. [doi:10.1002/mbo3.1006]32112625
2019Elizalde-Díaz JP, Hernández-Lucas I, Medina-Aparicio L, Dávalos A, Leija A, Alvarado-Affantranger X, García-García JD, Hernández G, Garcia-de Los Santos A. (2019). "Rhizobium tropici CIAT 899 copA gene plays a fundamental role in copper tolerance in both free life and symbiosis with Phaseolus vulgaris.". MICROBIOLOGY-SGM. 165(6):651-661. [doi:10.1099/mic.0.000803]31081746
2018González-Sánchez A, Cubillas CA, Miranda F, Dávalos A, García-de Los Santos A. (2018). "The ropAe gene encodes a porin-like protein involved in copper transit in Rhizobium etli CFN42". MICROBIOLOGYOPEN. 7(3):-. [doi:10.1002/mbo3.573]29280343
2017Cubillas, C., Miranda-Sánchez, F., González-Sánchez, A., Elizalde, J.P., Vinuesa, P., Brom, S., García-de los Santos, A.. (2017). "A comprehensive phylogenetic analysis of copper transporting P1BATPases from bacteria of the Rhizobiales order uncovers multiplicity, diversity and novel taxonomic subtypes". MICROBIOLOGYOPEN. 6(4):-. [doi:10.1002/mbo3.452]28217917
2014Cubillas, Ciro, Vinuesa, Pablo, Tabche, Maria Luisa, Davalos, Araceli, Vazquez, Alejandra, Hernandez-Lucas, Ismael, Romero, David, Garcia-de los Santos, Alejandro. (2014). "The cation diffusion facilitator protein EmfA of Rhizobium etli belongs to a novel subfamily of Mn<sup>2+</sup>/Fe<sup>2+</sup> transporters conserved in a-proteobacteria". Metallomics. 6(10):1808-1815. [doi:10.1039/c4mt00135d]25054342
2014Chang, F.M.J., Coyne, H.J., Cubillas Ramírez, Ciro Alberto, Vinuesa Fleischmann, Pablo, Fang, X.Y., Ma, Z., Ma, D.J., Helmann, J.D., García de los Santos, Alejandro, Wang, Y.X., Dann, C.E., Giedroc, D.P.. (2014). "Cu(I)-mediated allosteric switching in a copper-sensing operon repressor (CsoR)". JOURNAL OF BIOLOGICAL CHEMISTRY. 289(27):19204-19217. [doi:10.1074/jbc.M114.556704]24831014
2013Cubillas Ramírez, Ciro Alberto, Vinuesa Fleischmann, Pablo, Tabche, M.L., García de los Santos, Alejandro. (2013). "Phylogenomic analysis of Cation Diffusion Facilitator proteins uncovers Ni2+/Co2+ transporters". Metallomics. 5(12):1634-1643. [doi:10.1039/c3mt00204g]24077251
2011Villaseñor Toledo, Tomas, Dávalos Rodríguez, Araceli Elvira, Lozano Aguirre Beltrán, Luis Fernando, Romero Camarena, David René, García de los Santos, Alejandro. (2011). "Housekeeping genes essential for pantothenate biosynthesis are plasmid-encoded in Rhizobium etli and Rhizobium leguminosarum". Bmc Microbiology. 11():66-66. [doi:10.1186/1471-2180-11-66]21463532
2008Garcfa-de los Santos, Alejandro, Lopez, Erika, Cubillas, Ciro A., Noel, K. Dale, Brom, Susana, Romero, David. (2008). "Requirement of a plasmid-encoded catalase for survival of Rhizobium etli CFN42 in a polyphenol-rich environment". Applied And Environmental Microbiology. 74(8):2398-2403. [doi:10.1128/AEM.02457-07]18310436
2007Romero, David, Garcia-De Los Santos, Alejandro, Brom, Susana. (2007). "Essential plasmids in Rhizobium.". Plasmid. 57(2):227-227.
2007Brom, Susana, Garcia-De Los Santos, Alejandro, Romero, Laura Cervantes David. (2007). "Conjugative transfer of Rhizobium plasmids.". Plasmid. 57(2):220-220.
2007Ramirez-Trujillo, J. A., Encarnacion, S., Salazar, E., de los Santos, A. Garcia, Dunn, M. F., Emerich, D. W., Calva, E., Hernandez-Lucas, I.. (2007). "Functional characterization of the Sinorhizobium meliloti acetate metabolism genes aceA, SMc00767, and glcB". Journal Of Bacteriology. 189(16):5875-5884. [doi:10.1128/JB.00385-07]17526694
2005Guillen-Navarro, K, Araiza, G, Garcia-de los Santos, A, Mora, Y, Dunn, MF. (2005). "The Rhizobium etli bioMNY operon is involved in biotin transport". Fems Microbiology Letters. 250(2):209-219. [doi:10.1016/j.femsle.2005.07.020]16099603
2004Brom Klanner, Susana, Girard Cuesy, María de Lourdes, Tun Garrido, Cristina Soleda, García de los Santos, Alejandro, Bustos Arcos, Virginia Patricia, González Zúñiga, Víctor Manuel, Romero Camarena, David René. (2004). "Transfer of the symbiotic plasmid of Rhizobium etli CFN42 requires cointegration with p42a, which may be mediated by site-specific recombination". Journal Of Bacteriology. 186(22):7538-7548. [doi:10.1128/JB.186.22.7538-7548.2004]15516565
2003Vargas, MD, Encarnacion, S, Davalos, A, Reyes-Perez, A, Mora, Y, Garcia-de los Santos, A, Brom, S, Moral, J. (2003). "Only one catalase, katG, is detectable in Rhizobium etli, and is encoded along with the regulator OxyR on a plasmid replicon". MICROBIOLOGY-SGM. 149(5):1165-1176. [doi:10.1099/mic.0.25909-0]12724378
2002Garcia-de los Santos, A, Morales, A, Baldoma, L, Clark, SRD, Brom, S, Yost, CK, Hernandez-Lucas, I, Aguilar, J, Hynes, MF. (2002). "The glcB locus of Rhizobium leguminosarum VF39 encodes an arabinose-inducible malate synthase". Canadian Journal Of Microbiology. 48(10):922-932. [doi:10.1139/w02-091]12489782
2002Brom Klanner, Susana, Girard Cuesy, María de Lourdes, García de los Santos, Alejandro, Sanjuan-Pinilla, J.M., Olivares, J., Sanjuan, J.. (2002). "Conservation of plasmid-encoded traits among bean-nodulating Rhizobium species". Applied And Environmental Microbiology. 68(5):2555-2561. [doi:10.1128/AEM.68.5.2555-2561.2002]11976134
2000Brom, S, Garcia-de los Santos, A, Cervantes, L, Palacios, R, Romero, D. (2000). "In Rhizobium etli symbiotic plasmid transfer, nodulation competitivity and cellular growth require interaction among different replicons". Plasmid. 44(1):34-43. [doi:10.1006/plas.2000.1469]10873525
1999Wang, ET, Roel, MA, Garcia-de los Santos, A, Martinez-Romero, Julio, Cevallos, MA, Martinez-Romero, E. (1999). "Rhizobium etli bv. mimosae, a novel biovar isolated from Mimosa affinis". INTERNATIONAL JOURNAL OF SYSTEMATIC BACTERIOLOGY. 49(4):1479-1491. [doi:10.1099/00207713-49-4-1479]10555329
1997GarciadelosSantos, A, Brom, S. (1997). "Characterization of two plasmid-borne lps beta loci of Rhizobium etli required for lipopolysaccharide synthesis and for optimal interaction with plants". Molecular Plant-Microbe Interactions. 10(7):891-902. [doi:10.1094/MPMI.1997.10.7.891]9304861
1992BROM, S, DELOSSANTOS, AG, STEPKOWSKI, T, FLORES, M, DAVILA, G, ROMERO, D, PALACIOS, R. (1992). "DIFFERENT PLASMIDS OF Rhizobium-leguminosarum BV phaseoli ARE REQUIRED FOR OPTIMAL SYMBIOTIC PERFORMANCE". Journal Of Bacteriology. 174(16):5183-5189. [doi:10.1128/jb.174.16.5183-5189.1992]1644746
1991BROM, S, DELOSSANTOS, AG, DELOURDESGIRARD, M, DAVILA, G, PALACIOS, R, ROMERO, D. (1991). "High-frequency rearrangements in Rhizobium leguminosarum bv. phaseoli plasmids". Journal Of Bacteriology. 173(3):1344-1346. [doi:10.1128/jb.173.3.1344-1346.1991]1991727