title: Identification of differentially expressed genes by cDNA-AFLP technique during heat stress in cowpea nodules.
abstract: Legume nodules formed by diazotrophic microorganisms are active sites for biological nitrogen fixation (BNF). In tropical regions, a significant part of N supply for soybean, peanut and bean crops is derived from BNF, which is nevertheless often limited by high temperature stress. In contrast, cowpea nodules are very resistant to high temperatures. To understand the molecular bases of thermotolerance during BNF under heat stress, we have used cDNA-amplified fragment length polymorphism experiments to identify differentially expressed transcripts from cowpea nodules subjected to heat shock treatment. The expression profiles obtained showed approximately 600 bands, 55 up-regulated and nine corresponding to genes repressed by heat stress. Twenty transcript-derived fragments were isolated, cloned and sequenced. The Vigna unguiculata nodule and stress response transcripts present similarities to those that encode low molecular weight heat shock proteins, wound-induced proteins, disease resistance protein, and xylan endohydrolase isoenzyme, as well as different housekeeping genes. The differential expression of 15 genes was confirmed by using Northern blot or reverse Northern hybridization experiments.
authors.affiliation: Laboratório de Genética Molecular Vegetal, Departamento de Genética, Universidade Federal do Rio de Janeiro, CP 68011, CEP 21941-970, Rio de Janeiro, Brazil.
authors.forename: Jean Luiz
authors.initials: JL
authors.lastname: Simões-Araújo
authors.forename: Roberta L
authors.initials: RL
authors.lastname: Rodrigues
authors.forename: Liliane B
authors.initials: LB
authors.lastname: de A  Gerhardt
authors.forename: Jorge M C
authors.initials: JM
authors.lastname: Mondego
authors.forename: Márcio
authors.initials: M
authors.lastname: Alves-Ferreira
authors.forename: Norma Gouvêa
authors.initials: NG
authors.lastname: Rumjanek
authors.forename: Márcia
authors.initials: M
authors.lastname: Margis-Pinheiro
mesh_terms: D020869:Gene Expression Profiling / Q000379:methods*; D006360:Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D018869:Heat-Shock Response / Q000502:physiology*; D008969:Molecular Sequence Data; D018532:Pisum sativum / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D018514:Plant Structures / Q000378:metabolism*; D012150:Polymorphism, Restriction Fragment Length; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
chemical_list: D006360:Heat-Shock Proteins; D010940:Plant Proteins