Proteomic Analysis of Seed Dormancy in Arabidopsis

Abstract

The mechanisms controlling seed dormancy in Arabidopsis (Arabidopsis thaliana) have been characterized by proteomics using the dormant (D) accession Cvi originating from the Cape Verde Islands. Comparative studies carried out with freshly harvested dormant and after-ripened non-dormant (ND) seeds revealed a specific differential accumulation of 32 proteins. The data suggested that proteins associated with metabolic functions potentially involved in germination can accumulate during after-ripening in the dry state leading to dormancy release. Exogenous application of abscisic acid (ABA) to ND seeds strongly impeded their germination, which physiologically mimicked the behavior of D imbibed seeds. This application resulted in an alteration of the accumulation pattern of 71 proteins. There was a strong down-accumulation of a major part (90%) of these proteins, which were involved mainly in energetic and protein metabolisms. This feature suggested that exogenous ABA triggers proteolytic mechanisms in imbibed seeds. An analysis of de novo protein synthesis by two-dimensional gel electrophoresis in the presence of [ 35 S]-methionine disclosed that exogenous ABA does not impede protein biosynthesis during imbibition. Furthermore, imbibed D seeds proved competent for de novo protein synthesis, demonstrating that impediment of protein translation was not the cause of the observed block of seed germination. However, the two-dimensional protein profiles were markedly different from those obtained with the ND seeds imbibed in ABA. Altogether, the data showed that the mechanisms blocking germination of the ND seeds by ABA application are different from those preventing germination of the D seeds imbibed in basal medium.

ROS Signaling in Seed Dormancy Alleviation

“…1), which suggests that seed imbibition increased the susceptibility of storage proteins to proteolysis, independently of the subsequent completion of germination. This would allow the imbibed nongerminating dormant seeds to sustain a minimal metabolic activity during imbibition, a finding that is in accordance with the recent results of Chibani et al 12 Therefore, in addition to the data provided by Job et al, 10 our results demonstrate that carbonylation can play a regulatory role and should not always be regarded as an unfavorable mechanism in developmental processes.…”

Protein Tyrosine Kinases and Protein Tyrosine Phosphatases Are Involved in Abscisic Acid-Dependent Processes in Arabidopsis Seeds and Suspension Cells

“…Similarly, Chibani et al (2006) estimated that the amounts of 57 proteins decreased and the amounts of seven proteins increased in nondormant Arabidopsis seeds in response to ABA. It was suggested, therefore, that protein abundance is modulated through proteolytic mechanisms (Chibani et al, 2006). We detected about 140 Tyr phosphorylated protein spots in extracts from Arabidopsis seeds.…”

Nitrile-specifier Proteins Involved in Glucosinolate Hydrolysis in Arabidopsis thaliana

“…Evidence that the transcripts of the AtNSP2 and related genes described in this paper are, however, translated in planta is provided by a series of proteomic studies. Peptides corresponding to AtNSP1 and AtNSP2 were identified in the A. thaliana seed proteome (59,60), and the protein encoded by At3g16410 was identified as major root protein in a proteomics study of eight A. thaliana ecotypes (61).…”