Gene expression programs during Brassica oleracea seed maturation, osmopriming, and germination are indicators of progression of the germination process and the stress tolerance level

• Published in: Plant physiology (Bethesda) 2005, Vol.137 (1), p.354-368
• Main Authors: Soeda, Y, Konings, M.C.J.M, Vorst, O, Houwelingen, A.M.M.L. van, Stoopen, G.M, Maliepaard, C.A, Kodde, J, Bino, R.J, Groot, S.P.C, Geest, A.H.M. van der
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Brassica - genetics; Brassica - growth & development; Brassica - physiology; Brassica oleracea; Complementary DNA; desiccation (plant physiology); Drying; Environmental Stress and Adaptation; expressed sequence tags; Fundamental and applied biological sciences. Psychology; Gene expression; Gene Expression Profiling; gene expression regulation; Gene Expression Regulation, Developmental - physiology; Gene Expression Regulation, Plant - physiology; Genes; Germination; Germination and dormancy; microarray technology; Oligonucleotide Array Sequence Analysis; osmotic pressure; Oxidative Stress; Plant physiology and development; Plants; RNA; seed germination; Seed maturation; seed quality; Seeds; Seeds - physiology; Stress tolerance; Time Factors; Water; water stress
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.104.051664

During seed maturation and germination, major changes in physiological status, gene expression, and metabolic events take place. Using chlorophyll sorting, osmopriming, and different drying regimes, Brassica oleracea seed lots of different maturity, stress tolerance, and germination behavior were created. Through careful physiological analysis of these seed lots combined with gene expression analysis using a dedicated cDNA microarray, gene expression could be correlated to physiological processes that occurred within the seeds. In addition, gene expression was studied during early stages of seed germination, prior to radicle emergence, since very little detailed information of gene expression during this process is available. During seed maturation expression of many known seed maturation genes, such as late-embryogenesis abundant or storage-compound genes, was high. Notably, a small but distinct subgroup of the maturation genes was found to correlate to seed stress tolerance in osmoprimed and dried seeds. Expression of these genes rapidly declined during priming and/or germination in water. The majority of the genes on the microarray were up-regulated during osmopriming and during germination on water, confirming the hypothesis that during osmopriming, germination-related processes are initiated. Finally, a large group of genes was up-regulated during germination on water, but not during osmopriming. These represent genes that are specific to germination in water. Germination-related gene expression was found to be partially reversible by physiological treatments such as slow drying of osmoprimed seeds. This correlated to the ability of seeds to withstand stress.