Abstract
We isolated a recessive Arabidopsis slh1 mutant which showed growth defect in low humidity condition from Ds-transposon tagged mutant lines. We observed dead cells, callose and autofluorescence compounds accumulated in rosette leaves and upregulation of marker genes for hypersensitive response by low humidity, suggesting that slh1 mutant exhibits constitutive expression of the defense responses and cell death. NahG transgene partially suppressed slh1 phenotype, implying the activation of salicylic acid dependent signaling pathway in slh1. Ds inserts into the R-gene that locates in the complex R-gene cluster locus over 50kb on chromosome 5. Unfortunately, 2 alleles showed no phenotype and genomic fragment of this R-gene could not suppress slh1 phenotype, indicating that Ds insertion is not cause of slh1. slh1 was mapped within 83.6kb around the Ds insertion site. We found a candidate gene which contains 3bp insertion mutation typical for the footprint of Ds transposition. Complementation experiment is in progress.
