cDNA-AFLP reveals differentially expressed genes related to cell aggregation of Azospirillum brasilense

FEMS Microbiol Lett. 2006 Dec;265(2):186-94. doi: 10.1111/j.1574-6968.2006.00482.x.


The response regulatory gene flcA controls the differentiation process of Azospirillum brasilense from vegetative state to cyst-like forms, both in culture and in association with plants. In contrast to the wild type parental strain Sp7, strain Sp72002, a Tn5 induced flcA(-) mutant, does not aggregate, does not differentiate from motile, vibroid cells into nonmotile, cyst-like forms and lacks some of the exopolysaccharide material on its cell surface. Here we aimed to identify differentially expressed genes whose expression could be modulated by flcA. Using cDNA-amplified fragment length polymorphism, we detected 81 transcript-derived fragments showing differential expression during exponential growth phase in an aggregation-inducing medium containing high C : N ratio. The fragments were sequenced and analyzed, and expression of ten genes encoding known proteins was compared between the two strains by reverse transcriptase polymerase chain reaction-(RT-PCR). RT-PCR analyses confirmed the differential patterns observed by cDNA-AFLP in nine of those genes. Among them are genes homologous to nodQ, involved in sulfation; narK, involved in nitrite/nitrate transport, and flp, involved in autoaggregation; as well as genes encoding a biopolymer transport protein, and the signal recognition particle. This work demonstrates the usefulness of the cDNA-AFLP approach to reveal genes that are differentially expressed during aggregation in Azospirillum brasilense and provides insights into the aggregation process of this bacterium.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Azospirillum brasilense / genetics*
  • Azospirillum brasilense / physiology*
  • Bacterial Proteins / genetics*
  • DNA, Complementary
  • Flocculation
  • Gene Expression Profiling
  • Gene Expression Regulation, Bacterial / genetics*
  • Molecular Sequence Data
  • Nucleic Acid Amplification Techniques
  • Polymorphism, Genetic
  • Polysaccharides, Bacterial / genetics*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Transcription Factors / genetics*


  • Bacterial Proteins
  • DNA, Complementary
  • FlcA protein, Azospirillum brasilense
  • Polysaccharides, Bacterial
  • Transcription Factors

Associated data

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