Post-genomics dissection of seed dormancy and germination

Studies of genome expression in Arabidopsis have provided important new information about mechanisms controlling germination and suggest new avenues to explore. Unexpectedly, changes in transcription and protein metabolism were observed in the ‘dry’ 1 1 Mature seeds are usually described as dry, although they contain some water, typically in the range of 5–10%, depending on the species. Furthermore, recent data (see Ref. [23]) indicate that this residual water is not uniformly distributed in the seed tissues, but rather that some areas may contain enough water to support gene expression. Within the text, we use quotes to specify this important point. quiescent seed state, suggesting that careful controls are required for seed expression-profiling experiments. Changes in the transcriptome following seed imbibition suggest a dynamic relationship between RNAs ‘stored’ from seed maturation, and synthesis of new RNAs related to post-imbibition germinating- or dormant-seed states. Recent post-genomics approaches suggest that RNA translation or post-translation are the major levels of control for germination completion and that transcriptome changes might reflect alteration in dormancy status or enhancement of germination vigour and effects on post-germination functions that relate to seedling growth.