Abstract
Arabidopsis JB101 line, which contains a mutation in the fad7 locus, is defective in an ω-3 fatty acid desaturase. This line shows an increased tolerance to salt stress. However, wild-type FAD7 gene failed to complement the salt-tolerant phenotype of JB101, suggesting that the salt tolerance was not due to the fad7 mutation. Genetic mapping revealed that JB101 contained the second mutation close to the fad7 locus, designated stm1 (for salt tolerant mutant1), that conferred the tolerance to salt stress. STM1 gene encodes a novel protein with putative ankyrin repeat and transmembrane regions. Expression analysis using an STM1 promoter::GUS fusion gene and RT-PCR suggested that STM1 is expressed in roots, leaves, stems, and floral tissues. Additionally, the expression of STM1 was induced by salt stress. Involvement of STM1 in salt stress response will be discussed.
