Proteome-Wide Characterization of Seed Aging in Arabidopsis: A Comparison between Artificial and Natural Aging Protocols  

Abstract

A variety of mechanisms have been proposed to account for the extension of life span in seeds (seed longevity). In this work, we used Arabidopsis (Arabidopsis thaliana) seeds as a model and carried out differential proteomics to investigate this trait, which is of both ecological and agricultural importance. In our system based on a controlled deterioration treatment (CDT), we compared seed samples treated for different periods of time up to 7 d. Germination tests showed a progressive decrease of germination vigor depending on the duration of CDT. Proteomic analyses revealed that this loss in seed vigor can be accounted for by protein changes in the dry seeds and by an inability of the low-vigor seeds to display a normal proteome during germination. Furthermore, CDT strongly increased the extent of protein oxidation (carbonylation), which might induce a loss of functional properties of seed proteins and enzymes and/or enhance their susceptibility toward proteolysis. These results revealed essential mechanisms for seed vigor, such as translational capacity, mobilization of seed storage reserves, and detoxification efficiency. Finally, this work shows that similar molecular events accompany artificial and natural seed aging.

Substrates of the Arabidopsis thaliana Protein Isoaspartyl Methyltransferase 1 Identified Using Phage Display and Biopanning

“…Translation of stored mRNA but not production of new transcripts is known to be vital for the completion of seed germination (75,76). Together, the stored proteome and intact, stored mRNA provide the germinating seed with two options for obtaining a particular functional enzyme system after storage in the dehydrated state and without recourse to transcription; 1) use of pre-existing protein X that is functional or can be made to be functional or 2) use of pre-existing mRNA from which to manufacture de novo, functional protein X.…”

Noninvasive diagnosis of seed viability using infrared thermography

“…The bars on the far right of the graphs show time windows in which seed types differed significantly at P < 0.001. are critical to whether a seed will germinate or die (23,24). Nucleic acids, proteins, and lipids are inevitably subject to oxidative damage during seed maturation drying and, even more so, during storage and aging (25)(26)(27)(28); repair very early in imbibition is key to successful germination (23-25).…”

An Arabidopsis ATP-Dependent, DEAD-Box RNA Helicase Loses Activity upon IsoAsp Formation but Is Restored by PROTEIN ISOASPARTYL METHYLTRANSFERASE

“…From these and other data (Rajjou et al, 2004(Rajjou et al, , 2008(Rajjou et al, , 2012Kimura and Nambara, 2010;An and Lin, 2011;He et al, 2011;Kushwaha et al, 2012), it has been hypothesized that the proteins of the translational machinery could be viewed as an Achilles heel of orthodox seed longevity (Kushwaha et al, 2013) and may be a major target requiring protection and PIMT-mediated repair in organisms capable of entering a period of quiescence. One such target of rPIMT1 was PLANT RNA HELICASE75 (PRH75), a presumptive ATP-dependent, DEAD-box, RNA helicase (EC 3.6.4.13) targeted to the nucleolus and presumably involved in translation by assisting ribosome maturation (Lorkovic et al, 1997(Lorkovic et al, , 2004.…”