03255nam a2200217 a 450000100080000000500110000800800410001910000190006024501020007926001570018150000140033852025630035265000110291565000260292665300110295265300080296365300100297170000170298170000170299870000220301518869522011-04-29       2011    bl uuuu     u00u1 u    #d1 aMARTINS, P. K.  aPhylogenetic and comparative gene expression analysis of citrus WRKY transcription factor family.  aIn: SIMPÓSIO BRASILEIRO DE GENÉTICA MOLECULAR DE PLANTAS, 3, 2011, Ilhéus. Resumos. [S. l.]: Sociedade Brasileira de Genética, 2011. 1 CD-ROM.c2011  apdf 35130  aPlants have a variety of active defense mechanisms to protect themselves from pathogen infection. Plant defense response results from the transcriptional activation of a large number of genes upon pathogen infection or treatment with pathogen elicitors. Among them, WRKY proteins are considered important transcriptional regulators in defense signaling, including the activation of SAR (systemic acquired resistance). Several genes regulating plant defense, such as NPR1 and PR (Pathogenesis-related proteins), have W-box elements in their promoters that are specifically recognized by WRKY proteins also required for induction or expression. The defining feature of WRKY transcription factors is their DNA binding domain. The WRKY domain is about 60 residues in length that contains the WRKY signature and also an atypical zinc-finger structure at the C-terminus (Cx4?5Cx22?23HxH or Cx7Cx23HxC). The aim of this work was to identify all potential WRKY transcription factors in citrus, retrieved from the CitEST (Citrus ESTs) database and to construct a phylogenetic tree with orthologs from Arabidopsis thaliana and Oryza sativa. To find ESTs coding for WRKY proteins in citrus we performed a tBLASTn search on the CitEST database. The WRKY domain sequences of seven Arabidopsis WRKY family members each representing one of the WRKY subgroups were used as query sequences. Phylogenetic tree were constructed by the neighbor-joining (NJ) method in MEGA 4. NJ analysis was performed with the Pairwise Deletion option and the Poisson correction. For statistical reliability, bootstrap analysis was conducted with 1,000 replicates to assess statistical support for each node. The primary search resulted in 71 non-redundant hits, of which 9 were removed as they did not contain the conserved WRKY domain signature. The remaining 62 sequences were used to construct the phylogenetic tree; this analysis identified 19 unigenes for the group 1; 6 unigenes for the subgroup 2a, 3 unigenes for the subgroup 2b, 12 unigenes for the subgroup 2c, 13 unigenes for the group 2d, 9 unigenes for subgroup 2e and 7 unigenes for the group 3. To complete the phylogenetic analysis, WRKY sequences from the draft sequencing of the genomes of Citrus clementina and C. sinensis will be included. We are particularly interested in WRKY proteins involved in biotic stress, so the next step will be to evaluate the transcriptional profile of some WRKY genes under different biotic stress conditions. This study will be crucial to select candidates for citrus genetic transformation.  aCitrus  atranscription factors  aCitEST  aSAR  aW-box1 aMAFRA, V. S.1 aKISHI, L. T.1 aFREITAS-ASTUA, J.