Identification and Expression Analysis of Two Arabidopsis LRR-Protein Encoding Genes Responsive to Some Abiotic Stresses

AbstractTwo Arabidopsis thaliana genes, psr9.2 and psr9.4 appearedto be highly similar to a phosphate-starved induced gene,psr9, isolated from Brassica nigra suspension cells.Sequence analysis classified the encoded polypeptides asmembers of leucine-rich repeat (LRR) proteins superfamily.The sequence of psr9 proteins comprise a unique N-terminalregion encompassing a coiled-coil structure proceedingeleven LRRs along the C-terminal. Expression patternanalysis showed the responsiveness of these genes to variousenvironmental conditions. Although both psr9 genes,psr9.2 and psr9.4, are expressed throughout the plant, theexpression of psr9.2 was higher in the root whereas psr9.4expression was prominent in the shoot. The expression levelswere increased proportional to the duration of phosphatedeprivation treatment. Plants exposed to cold temperatureexpressed both genes at high levels in both roots andshoots. In contrast, heat shock increased the expressionlevels of both genes in the shoots while reducing it in roots.High-salt treatment upregulated the expression of psr9genes only in the roots. These data may suggest distinctroles for psr9 genes during plant response to various environmentalconditions.