The cis-elements included Ca2 +-responsive, abiotic stress responsive, light and circadian rhythm SP600125 molecular weight regulation, disease resistance and seed development, such as: ABRERATCAL, ABRELATERD1, ACGTATERD1, BOXLCOREDCPAL, CARGCW8GAT, CIACADIANLELHC, CTRMCAMV35S, DPBFCOREDCDC3, EECCRCAH1, DOFCOREZM, GT1CONSENSUS, INRNTPSADB, POLASIG2, RYREPEATGMGY2, RYREPEATLEGUMINBOX, SEBFCONSSTPR10A, SEF4MOTIFGM7S, SP70A, and TATABOX2 ( Table 2). EST data could provide useful information for gene expression

research. There are about 66,051 foxtail millet ESTs in the NCBI EST database. Thus, EST mining and thr whole-genome AZD2281 chemical structure shotgun (WGS) database were employed to analyze transcript levels of SiCKX genes. The coding sequences of SiCKX genes were used to query the EST database using the megablast tool. Based on tissue and organ types, the EST data were classified into eight groups ( Table 3). The results indicated that all SiCKX genes had expression data support. Expression data for all the SiCKX genes

were obtained for seedlings and leaves. The EST number for SiCKX3 was highest, up to 25. Expression data for SiCKX genes SiCKX1 and SiCKX10 were checked in eight tissue types. The relative transcript levels of the SiCKX genes in germinating embryos under 6-BA, NaCl, and PEG treatments are shown in Fig. 6. Transcripts of SiCKX1, SiCKX3, SiCKX4, SiCKX5, SiCKX8, SiCKX9, and SiCKX10 were induced

by all three treatments. SiCKX6 and SiCKX7 were up-regulated in embryos treated with 6-BA and PEG, whereas the expression levels were unchanged in embryos under NaCl treatment, and SiCKX2 and SiCKX11 expressions were induced only by 6-BA. In 1971, Pačes et al. described CKX activity in crude tobacco cell culture extracts [17]. Later, similar activity was found in maize kernels [51]. Since then many papers have reported CKX activity from a variety of tissues and species. In recent years, with whole genome sequencing, before the CKX gene family was thoroughly investigated in many plant species using comparative genomic approaches. CKX enzymes are encoded by a multigene family with varying numbers of members in different plant species [37]. In the present work, we isolated 11 CKX genes from foxtail millet in silico. cis-elements play essential roles in the regulation of gene expression by controlling the efficiency of promoters. Thus research on cis-elements could lay a foundation for further functional analysis of the SiCKX genes.