Re-examination of the Gene Family in Barley ( L.) Indicates a Role in the Regulation of Starch Synthesis.

The factor () gene family is a large plant-specific transcription factor family, which plays important roles in regulating plant growth and development. A role in starch synthesis is among the multiple functions of this family of transcription factors. Barley ( L.) is one of the most important cereals for starch production. However, there are limited data on the contribution of AP2 transcription factors in barley. In this study, we used the recently published barley genome database (Morex) to identify 185 genes of the family. Compared with previous work, we identified 64 new genes in the gene family and corrected some previously misannotated and duplicated genes. After phylogenetic analysis, genes were classified into four subfamilies and 18 subgroups. Expression profiling showed different patterns of spatial and temporal expression for genes. Most of the 12 genes analyzed using quantitative reverse transcription-polymerase chain reaction had similar expression patterns when compared with those of starch synthase genes in barley, except for and . is homologous to , which negatively regulates the synthesis of rice starch. Luciferase reporter gene, and yeast one-hybrid assays showed that bound the promoter of and . Thus, might be an interesting candidate gene to further explore the mechanisms involved in the regulation of starch synthesis in barley.