title: A comparative transcriptomic analysis of the extremely boron tolerant plant Puccinellia distans with the moderately boron tolerant Gypsophila arrostil.
abstract: The Turkish ecotype of Puccinellia distans displays exceptional boron (B) tolerance, >1,250 mg B L⁻¹, compared to <50 mg B L⁻¹ for Gypsophila arrostil. In the present study, we compare the molecular basis for the difference in B tolerance between the two species by constructing high B-responsive suppression subtractive hybridization libraries to identify the upregulated genes. A total of 219 and 113 unique non-redundant expressed sequence tags (ESTs) were identified and functionally classified in P. distans and G. arrostil, respectively. In addition, 63 ESTs were down-regulated in P. distans in response to high B. The majority of the high B upregulated genes belong to four categories: metabolism, protein synthesis, cellular organization, and stress/defense. We hypothesize that the superior B tolerance exhibited by P. distans may be due to its ability to restrict the accumulation of B in plant tissues through the upregulated expression of efflux transporters comparable to the Bot1 transporter of barley. In addition, our results are consistent with the view that other molecular mechanisms involved in stress/defense, such as detoxification, anti-oxidative, and signaling pathways, are needed to tolerate B-toxicity stress.
  
  
  CONCLUSIONS
  The molecular basis of boron tolerance of two plant species (Puccinellia distans and Gypsophila arrostil) that differ greatly in their boron tolerance was studied in this manuscript.
authors.affiliation: Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3102, USA. priya_padma999@yahoo.com
authors.forename: Priya
authors.initials: P
authors.lastname: Padmanabhan
authors.forename: Mehmet
authors.initials: M
authors.lastname: Babaoğlu
authors.forename: Norman
authors.initials: N
authors.lastname: Terry
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects / Q000235:genetics*; D001692:Biological Transport / Q000187:drug effects / Q000235:genetics; D001895:Boron / Q000633:toxicity*; D029748:Caryophyllaceae / Q000187:drug effects* / Q000235:genetics* / Q000378:metabolism; D020224:Expressed Sequence Tags; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D006109:Poaceae / Q000187:drug effects* / Q000235:genetics* / Q000378:metabolism; D014176:Protein Biosynthesis / Q000187:drug effects / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics
chemical_list: D010940:Plant Proteins; D001895:Boron