Proteomic Analysis of Arabidopsis Seed Germination and Priming

Abstract

To better understand seed germination, a complex developmental process, we developed a proteome analysis of the model plant Arabidopsis for which complete genome sequence is now available. Among about 1,300 total seed proteins resolved in two-dimensional gels, changes in the abundance (up-and down-regulation) of 74 proteins were observed during germination sensu stricto (i.e. prior to radicle emergence) and the radicle protrusion step. This approach was also used to analyze protein changes occurring during industrial seed pretreatments such as priming that accelerate seed germination and improve seedling uniformity. Several proteins were identified by matrix-assisted laser-desorption ionization time of flight mass spectrometry. Some of them had previously been shown to play a role during germination and/or priming in several plant species, a finding that underlines the usefulness of using Arabidopsis as a model system for molecular analysis of seed quality. Furthermore, the present study, carried out at the protein level, validates previous results obtained at the level of gene expression (e.g. from quantitation of differentially expressed mRNAs or analyses of promoter/reporter constructs). Finally, this approach revealed new proteins associated with the different phases of seed germination and priming. Some of them are involved either in the imbibition process of the seeds (such as an actin isoform or a WD-40 repeat protein) or in the seed dehydration process (e.g. cytosolic glyceraldehyde-3-phosphate dehydrogenase). These facts highlight the power of proteomics to unravel specific features of complex developmental processes such as germination and to detect protein markers that can be used to characterize seed vigor of commercial seed lots and to develop and monitor priming treatments.

The Effect of α-Amanitin on the Arabidopsis Seed Proteome Highlights the Distinct Roles of Stored and Neosynthesized mRNAs during Germination

“…Because our previous protein maps were obtained from seeds of the wild-type Ler ecotype (Gallardo et al, 2001(Gallardo et al, , 2002a, we first investigated the effect of the tt2-1 mutation on the mature dry seed proteome. Only a few protein spots showed reproducible variations in their accumulation level when comparing the tt2-1 seed proteome presently analyzed with that of the corresponding wild-type Ler seed proteome previously described.…”

“…We have initiated a global study of Arabidopsis seed germination by proteomics (Gallardo et al, 2001(Gallardo et al, , 2002a(Gallardo et al, , 2002b; http://seed.proteome.free.fr). In the present work, we wished to characterize those proteins for which accumulation level can be affected by a-amanitin during germination, thereby allowing the identification of genes that are under transcriptional control during this process.…”

“…Although it is widely documented that, in addition to the storage proteins, mature dry seeds accumulate during maturation a number of proteins that are involved in various cellular processes such as DNA replication and transcription, translation, metabolism, or defense mechanisms (e.g. see Bewley and Black, 1994;Gallardo et al, 2001Gallardo et al, , 2002aGallardo et al, , 2002b, their role and functionality has not yet been thoroughly documented. It is also known that mature dry seeds contain mRNAs stored during maturation, also called long-lived mRNAs to indicate that they can survive desiccation and remain active in dry quiescent embryos.…”

“…While the processes and genes regulating embryogenesis and maturation are being identified (Errampalli et al, 1991;Girke et al, 2000;BrocardGifford et al, 2003;Gallardo et al, 2003;Tzafrir et al, 2003), only very recent studies addressed the question of the exact requirements for germination, particularly in terms of de novo RNA and protein syntheses (Bradford et al, 2000;Bove et al, 2001;Gallardo et al, 2001Gallardo et al, , 2002aKoornneef et al, 2002;Potokina et al, 2002;van der Geest, 2002;Duque and Chua, 2003;Jabrin et al, 2003;Ogawa et al, 2003). Although it is widely documented that, in addition to the storage proteins, mature dry seeds accumulate during maturation a number of proteins that are involved in various cellular processes such as DNA replication and transcription, translation, metabolism, or defense mechanisms (e.g.…”

Focus Issue on Metabolism: Metabolites, Metabolites Everywhere

“…Whereas the recent quantum leap in our ability to study plant metabolism began with the development of transcriptomics and genomic sequencing, proteomics and metabolomics followed swiftly thereafter, with early examples of the application of these approaches also being published in Plant Physiology (Girke et al, 2000;Zhu and Wang, 2000;Gallardo et al, 2001;Roessner et al, 2001). These developing technologies have both confirmed a number of long-held hypotheses and additionally provided novel insights into plant function.…”