Characterization of LIM Gene Family and Stress Induced Expression Profiling in Brassica

The formation of actin bundles, a major higher-order cytoskeletal assembly, have been reported to trigger by LIM (Lin-11, Isl-1 and Mec-3 domains) genes, in higher plants; however, the stress resistance related functions of these genes are still not well known. In this study, we collected 22 LIM genes designated as Brassica rapa LIM (BrLIM) from the Brassica database and confirmed as LIM genes by sequence analysis and found a high degree of homology with LIM genes of other species. These genes also showed clear grouping with other recognized LIM proteins upon phylogenetic analysis. Additionally, organ specific expression of these genes was observed in Chinese cabbage plants, with BrPLIM2a, b, c, BrWLIM3a, BrPLIM2e, f and g only being expressed in flower buds and expression of them was high in the early flowering stages except for BrWLIM3a and BrPLIM2e. The remaining genes were expressed in almost all organs tested. These organ specific expressions were clearly correlated with the phylogenetic grouping as well. In addition, two BrLIMs responded to Fusarium oxysporum f. sp. conglutinans infection, while nine, ten, six, seven and eight BrLIMs responded to salt, ABA, pH5, pH7 and pH9 stress treatments in Chinese cabbage plants, respectively. Thus, the results of this study suggest that BrLIM genes may be involved in resistance against biotic and abiotic stresses in Brassica and might be useful resources for breeding stress resistance crops.