Phylogeny and expression profile analyses of oleate- and linoleate-desaturase genes in soybean

Oleate desaturase (FAD2) and linoleate desaturase (FAD3) are key genes regulating C18 fatty acids in plants. This paper presented a comparative analysis of the molecular evolution and gene-expression profile of all six FAD2 (FAD2.1~FAD2.6) and four FAD3 (FAD3.1~FAD3.4) genes in soybean. It showed that the FAD2 and FAD3 sequences were divided into two distinct clades, and significant collinearity was detected within the FAD2 or FAD3 group. The expression of FAD2.3 and FAD2.6 was high in seeds, while that of FAD2.1 and FAD2.5 was high in leaves and other tissues, indicating the function differentiations of these genes. FAD3.1, FAD3.3, FAD3.4 also perform specific tissue- or stage-expression. These genes perform transcription characteristics of multiple duplicate genes. Make a combination of molecular evolution and transcription analyses could obtain more information of gene function and evolutionary trends.