Abstract
In the root of Arabidopsis thaliana, the transcript of a gene encoding putative pathogenesis-related protein 1 (PR1) increases under far-red light illumination to the shoot. We designated the far-red light-inducible PR1-like gene as FPL. The deduced amino acid sequence of FPL shows about 60% identities to those of a basic PR1-like gene, AtPRB1 and a defense marker, PR-1, but its function and responses to various stimuli such as hormone, pathogen, and wounding remain unknown. Meanwhile, it has been reported that far-red light promotes ethylene production and increases sensitivity to ethylene. Therefore, we analyzed the response of FPL to ethylene in a wild-type plant and an ethylene receptor mutant, etr1. The level of FPL mRNA in the wild-type root was clearly increased by treatment with 1-aminocyclopropane-1-carboxylic acid, but in the etr1 mutant was not. The results indicate that the FPL gene is induced by ethylene in addition to far-red light.
