Identification of desiccation tolerance transcripts potentially involved in rape (Brassica napus L.) seeds...

To investigate regulatory processes and protective mechanisms leading to desiccation tolerance (DT) in seeds, cDNA amplified fragment length polymorphism (cDNA-AFLP) in conjunction with 128 primer combinations was used to detect differential gene expression in rape seeds in response to DT during seed development and germination. We obtained approximately 8000 transcript-derived fragments (TDFs), of which 394 TDFs with differential expression patterns ("sustained expression", "up-regulated", "couple with seed DT", and "down-regulated") were excised from gels and re-amplified by polymerase chain reaction (PCR). After sequencing and comparison with the National Center for Biotechnology Information database, 176 TDFs presented significant similarity with known genes that could be classified into the following categories: metabolism and energy, stress resistance and defense, storage, signal transduction, and other functional categories. Using semiquantitative reverse-transcription PCR and real-time PCR approaches, the significance of the differences was further confirmed in fresh seeds and dehydrated seeds. The genes that encode superoxide dismutase, peroxiredoxin, caleosin, oleosin S3, steroleosin, late embryogenesis abundant protein, glutathione reductase, β-glucosidase, S23 transcriptional repressor, and some heat-shock proteins could be associated with DT. The results of this study will aid in the identification of candidate genes for future experiments that seek to understand seed DT.