title: Transcriptomic analysis of the process of biofilm formation in Rhizobium etli CFN42.
abstract: Organisms belonging to the genus Rhizobium colonize leguminous plant roots and establish a mutually beneficial symbiosis. Biofilms are structured ecosystems in which microbes are embedded in a matrix of extracellular polymeric substances, and their development is a multistep process. The biofilm formation processes of R. etli CFN42 were analyzed at an early (24-h incubation) and mature stage (72 h), comparing cells in the biofilm with cells remaining in the planktonic stage. A genome-wide microarray analysis identified 498 differentially regulated genes, implying that expression of ~8.3 % of the total R. etli gene content was altered during biofilm formation. In biofilms-attached cells, genes encoding proteins with diverse functions were overexpressed including genes involved in membrane synthesis, transport and chemotaxis, repression of flagellin synthesis, as well as surface components (particularly exopolysaccharides and lipopolysaccharides), in combination with the presence of activators or stimulators of N-acyl-homoserine lactone synthesis This suggests that R. etli is able to sense surrounding environmental conditions and accordingly regulate the transition from planktonic and biofilm growth. In contrast, planktonic cells differentially expressed genes associated with transport, motility (flagellar and twitching) and inhibition of exopolysaccharide synthesis. To our knowledge, this is the first report of nodulation and nitrogen assimilation-related genes being involved in biofilm formation in R. etli. These results contribute to the understanding of the physiological changes involved in biofilm formation by bacteria.
authors.affiliation: Programa de Genómica Funcional de Procariotes, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Cuernavaca, Morelos, Mexico.|Facultad de Ciencias, Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de México, Apartado Postal 70-153, C.P. 0415, Cuernavaca, D.F., Mexico.|Centro de Investigación en Dinámica Celular, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, Cuernavaca, Morelos, 62209, Mexico.
authors.forename: Agustín
authors.initials: A
authors.lastname: Reyes-Pérez
authors.affiliation: Programa de Genómica Funcional de Procariotes, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Cuernavaca, Morelos, Mexico.
authors.forename: María Del Carmen
authors.initials: Mdel C
authors.lastname: Vargas
authors.affiliation: Programa de Genómica Funcional de Procariotes, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Cuernavaca, Morelos, Mexico.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Hernández
authors.affiliation: Red de Estudios Moleculares Avanzados, Instituto de Ecología, A. C. Coatepec 351, El Haya, Xalapa, Veracruz, Mexico.
authors.forename: Eneas
authors.initials: E
authors.lastname: Aguirre-von-Wobeser
authors.affiliation: Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, UNAM, Av. Universidad s/n, Col. Chamilpa, Cuernavaca, Morelos, Mexico.
authors.forename: Ernesto
authors.initials: E
authors.lastname: Pérez-Rueda
authors.affiliation: Programa de Genómica Funcional de Procariotes, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Cuernavaca, Morelos, Mexico. encarnac@ccg.unam.mx.
authors.forename: Sergio
authors.identifier: http://orcid.org/0000-0001-7889-1681
authors.initials: S
authors.lastname: Encarnacion
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives / Q000378:metabolism; D018441:Biofilms / Q000254:growth & development*; D004269:DNA, Bacterial / Q000032:analysis; D015964:Gene Expression Regulation, Bacterial; D046228:Microarray Analysis; D012329:RNA, Bacterial / Q000032:analysis; D042163:Rhizobium etli / Q000235:genetics* / Q000502:physiology; D059467:Transcriptome / Q000502:physiology*
chemical_list: D004269:DNA, Bacterial; D012329:RNA, Bacterial; C088386:homoserine lactone; D015107:4-Butyrolactone
keywords: Biofilm; Microarrays; Planktonic; Rhizobium etli; Sessile