An in silico approach to identify key elements in a subset of Spermine induced genes in A. thaliana

GONZALEZ, ME; RUIZ, OA; PIECKENSTAIN, FL

Mendoza

Congreso; XLVIII Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2012

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

A role for spermine (Spm) in A. thaliana resistance to Pseudomonas viridiflava  was previously described by our group. A. thaliana plants that accumulate Spm by overexpressing the SPERMINE SYNTHASE gene (35S::SPMS-9) were less susceptible to P. viridiflava than spermine synthase null mutants (spms-2) with reduced Spm levels, and wild type plants. Global changes in gene expression resulting from perturbation of Spm levels in planta was analized by transcript profiling of 35S::SPMS-9 and spms-2 plants. Analysis of gene ontology term enrichment demonstrated that many genes overexpressed in 35S::SPMS-9 participate in pathogen perception and defense responses. The aim of this work was to identify enrichment of cis-regulatory elements related to defense mechanisms within the subset of genes overexpressed in 35S::SPMS-9. Notably three known promoter motifs associated with defense responses were enriched within the gene subset. In addition, five genes (MPK3, NHL2, NHL3, AZF1 and AZF2) with a putative role in Spm-mediated resistance were found within the three subsets of genes enriched in cis-elements. Particularly, MPK3 is the A. thaliana orthologue of tobacco WIPK, a well-known Spm-responsive gene. The other four are probable orthologues of tobacco Spm-responsive genes. The obtained results and their implications on Spm-mediated resistance of A. thaliana to P. viridiflava are discussed.