Temporal and Spatial Expression of PR-5 Linusitin-Like Gene in Healthy and Ethylene-Treated Flax Plants

Linusitin-like protein (LIN1) is a new osmotin-like protein isolated from flax radicles. The LIN1 gene is developmentally regulated and accumulated in an organ-specific manner in healthy flax plants. In an attempt to find the role and function of the LIN1 gene, we followed its temporal and spatial expression in different flax tissues during development and its induction after diverse osmotic stresses. The LIN1 mRNA was differentially expressed among the various organs during flax blooming. It was not detected in flowers, stems, or leaves, but a positive signal was found in roots. The major sites of LIN1 expression in roots were in the lateral roots. The LIN1 gene was activated in leaf by treatment with ethylene but not by methyl jasmonate or methyl salicylate. To understand its stress-response expression better, we isolated the promoter region of LIN1. Analysis of the promoter region revealed that it contains several ATATT "root motif" elements and one AGCCGCC sequence that is conserved in most basic pathogenesis-related (PR) protein genes and is responsible for ethylene induction.