A novel high-throughput genetic screen for stress-responsive mutants of Arabidopsis thaliana reveals new loci involving stress responses.
Activation sequence-1 (as-1) cognate promoter elements are widespread in the promoters of plant defense-related genes as well as in plant pathogen promoters, and may play important roles in the activation of defense-related genes. The as-1-type elements are highly responsive to multiple stress stimuli such as jasmonic acid (JA), salicylic acid (SA), H(2)O(2), xenobiotics and heavy metals, and therefore provide a unique opportunity for identifying additional signaling components and cross-talk points in the various signaling networks. A single as-1-type cis-element-driven GUS reporter Arabidopsis line responsive to JA, SA, H(2)O(2), xenobiotics and heavy metals was constructed for mutagenesis. A large-scale T-DNA mutagenesis has been conducted in the reporter background, and an efficient high-throughput mutant screen was established for isolating mutants with altered responses to the stress chemicals. A number of mutants with altered stress responses were obtained, some of which appear to identify new components in the as-1-based signal transduction pathways. We characterized a mutant (Delta8L4) with a T-DNA insertion in the coding sequence of the gene At4g24275. The as-1-regulated gene expression and GUS reporter gene expression were altered in the Delta8L4 mutant, but there was no change in the expression of genes lacking as-1 elements in their promoters. The phenotype observed with the Delta8L4 mutant was further verified using RNAi plants for At4g24275 (8L4-RNAi), suggesting the feasibility of use of this high-throughput mutant screening in isolating stress-signaling mutants.
Rama Devi
S
S
Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA 50011, USA.
Chen
Xi
X
Oliver
David J
DJ
Xiang
Chengbin
C
D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism*; D015536:Down-Regulation; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics*; D016254:Mutagenesis, Insertional; D009154:Mutation / Q000235:genetics*; D030821:Plants, Genetically Modified; D015854:Up-Regulation
D029681:Arabidopsis Proteins