Higher Plant Stress Signaling Network Of Mutants And Analysis Of Transfer Of The Preliminary Study Of The Hs1 Gene Plant Drought Project

Activation sequence-1 (as-1) cognate promoter elements are widespread in the promoters of plant defense related genes as well as in plant pathogen gene promoters, playing 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), H₂O₂, xenobiotics and heavy metals, 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, H₂O₂, xenobiotics and heavy metals was constructed for mutagenesis. A large-scale T-DNA mutagenesis has been conducted in this 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 (D8L4) 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 D8L4 mutant, but there was no change in the expression of genes lacking as-1 elements in their promoters. The phenotype observed with the D8L4 mutant was further verified using At4g24275 RNAi plants (8L4-RNAi), suggesting the feasibility of use of this high-throughput mutant screening in isolating stress-signaling mutants.