title: Global changes in the transcript and metabolic profiles during symbiotic nitrogen fixation in phosphorus-stressed common bean plants.
abstract: Phosphorus (P) deficiency is widespread in regions where the common bean (Phaseolus vulgaris), the most important legume for human consumption, is produced, and it is perhaps the factor that most limits nitrogen fixation. Global gene expression and metabolome approaches were used to investigate the responses of nodules from common bean plants inoculated with Rhizobium tropici CIAT899 grown under P-deficient and P-sufficient conditions. P-deficient inoculated plants showed drastic reduction in nodulation and nitrogenase activity as determined by acetylene reduction assay. Nodule transcript profiling was performed through hybridization of nylon filter arrays spotted with cDNAs, approximately 4,000 unigene set, from the nodule and P-deficient root library. A total of 459 genes, representing different biological processes according to updated annotation using the UniProt Knowledgebase database, showed significant differential expression in response to P: 59% of these were induced in P-deficient nodules. The expression platform for transcription factor genes based in quantitative reverse transcriptase-polymerase chain reaction revealed that 37 transcription factor genes were differentially expressed in P-deficient nodules and only one gene was repressed. Data from nontargeted metabolic profiles indicated that amino acids and other nitrogen metabolites were decreased, while organic and polyhydroxy acids were accumulated, in P-deficient nodules. Bioinformatics analyses using MapMan and PathExpress software tools, customized to common bean, were utilized for the analysis of global changes in gene expression that affected overall metabolism. Glycolysis and glycerolipid metabolism, and starch and Suc metabolism, were identified among the pathways significantly induced or repressed in P-deficient nodules, respectively.
authors.affiliation: Centro de Ciencias Genómicas-Universidad Nacional Autónoma de México, 62209 Cuernavaca, Morelos, México. gina@ccg.unam.mx
authors.forename: Georgina
authors.initials: G
authors.lastname: Hernández
authors.forename: Oswaldo
authors.initials: O
authors.lastname: Valdés-López
authors.forename: Mario
authors.initials: M
authors.lastname: Ramírez
authors.forename: Nicolas
authors.initials: N
authors.lastname: Goffard
authors.forename: Georg
authors.initials: G
authors.lastname: Weiller
authors.forename: Rosaura
authors.initials: R
authors.lastname: Aparicio-Fabre
authors.forename: Sara Isabel
authors.initials: SI
authors.lastname: Fuentes
authors.forename: Alexander
authors.initials: A
authors.lastname: Erban
authors.forename: Joachim
authors.initials: J
authors.lastname: Kopka
authors.forename: Michael K
authors.initials: MK
authors.lastname: Udvardi
authors.forename: Carroll P
authors.initials: CP
authors.lastname: Vance
mesh_terms: D019295:Computational Biology; D020224:Expressed Sequence Tags; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D015723:Gene Library; D017343:Genes, Plant; D055442:Metabolome; D008969:Molecular Sequence Data; D009586:Nitrogen Fixation / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D027805:Phaseolus / Q000235:genetics / Q000378:metabolism*; D010758:Phosphorus / Q000172:deficiency / Q000378:metabolism*; D018749:RNA, Plant / Q000378:metabolism; D042162:Rhizobium tropici; D053204:Root Nodules, Plant / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D013559:Symbiosis; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D018749:RNA, Plant; D014157:Transcription Factors; D010758:Phosphorus