Expression profiling of genes involved in somatic and zygotic embryo development in cotton
We used a next-generation sequencing approach, Illumina Digital Gene Expression II (DGEII) technology, to Genome-wide profiling of gene expression during somatic (SE) and zygotic embryo (ZE) development. As a result, 4242 differentially expressed genes (DEGs) were identified between SE and ZE. Expression pattern cluster and functional classification analysis of the differentially expressed genes revealed that large number of genes indicative of response to stress highly expressed in somatic embryos. Combined with KEGG analysis and BLAST annotation, genes related to stress response in DEGs have been comprehensively analyzed, mainly including: ABA biosynthesis, ABA and JA (jasmonic acid) response, LEA (late embryogenesis abundant protein) family members, RD (responsive to dehydration) and ERD (early responsive to dehydration) family members, Hot Shock Proteins, WRKY family members and NAC family members. Semi-quantitative Reverse Transcriptase-PCR (RT-PCR) analysis was performed on 27 selected genes and and the results enhance that genes related to stress response were involved in SE development. Our main goal is to adapt the RNA-Seq technology to this notable development process and to analyse the gene expression profile. This is a systematical expression analysis focusing on somatic embryo development, and also a global comparison between somatic and zygotic embryo at transcript level. Therefore, this study might bring new insights into the regulation of somatic embryo development. Overall design: An analysis of differentially expressed genes at 3 parallel stages during somatic and zygotic embryo development in cotton by next-generation sequencing, using Illumina Digital Gene Expression II (DGE II) .