Toward Characterizing Seed Vigor in Alfalfa Through Proteomic Analysis of Germination and Priming

Abstract

Alfalfa, the most widely grown leguminous crop in the world, is generally exposed to severe salinity stress in Tunisia, notably affecting its germination performance. Toward a better understanding of alfalfa seed vigor, we have used proteomics to characterize protein changes occurring during germination and osmopriming, a pretreatment that accelerates germination and improves seedling uniformity particularly under stress conditions. The data revealed that germination was accompanied by dynamic changes of 79 proteins, which are mainly involved in protein metabolism, cell structure, metabolism, and defense. Comparative proteomic analysis also revealed 63 proteins specific to osmopriming, 65 proteins preferentially varying during germination, and 14 proteins common to both conditions. Thus, the present study unveiled the unexpected finding that osmopriming cannot simply be considered as an advance of germination-related processes but involves other mechanisms improving germination such as the mounting of defense mechanisms enabling osmoprimed seeds to surmount environmental stresses potentially occurring during germination. The present results therefore provide novel avenues toward understanding the mechanisms of invigoration of low vigor seeds by priming treatments that are widely used both in commercial applications and in developing countries (on farm seed priming) to better control crop yields.

Deciphering priming-induced improvement of rapeseed (Brassica napus L.) germination through an integrated transcriptomic and proteomic approach

“…Differential transcriptomic and proteomic studies have led to identification of many mRNAs and proteins during germination but without distinction between stored and de novo synthesized counterparts [10,11,55,58]. Galland et al [49] provided a detailed description of the dynamics of protein synthesis during the time course of germination, indicating that mRNA translation is both sequential and selective during this process.…”

“…Faster transition towards germinated state through priming may be considered as a result of the advanced germination metabolism [10,11], enhanced antioxidant activity [12,13] and repairing processes [14,15]. Moreover, seed priming often improves the stress tolerance of germinating seeds [11,16,17,18].…”

“…Moreover, seed priming often improves the stress tolerance of germinating seeds [11,16,17,18]. Priming procedure itself may generate a moderate abiotic stress during both soaking (e.g.…”

“…DNA microarray and proteomic analysis are now available as quite powerful complementary techniques for studying the complex interplay between genes and proteins during seed germination. Although separate transcriptome and proteome analyses of seed priming and germination have proven invaluable in identifying changes occurring during priming and postpriming germination [11,21], new strategies associating a holistic transcriptomic and proteomic approach are needed to distinguish protein accumulation driven directly by transcript abundance from that post-transcriptionally regulated.…”

Proteomic Analysis of Lettuce Seed Germination and Thermoinhibition by Sampling of Individual Seeds at Germination and Removal of Storage Proteins by Polyethylene Glycol Fractionation

“…Proteomics have been applied to investigate seed germination in many species, such as Arabidopsis (Arabidopsis thaliana; Gallardo et al, 2001Gallardo et al, , 2002Galland et al, 2014), rice (Oryza sativa; Yang et al, 2007), and pea (Pisum sativum; Wang et al, 2012b). These studies focused on seed germination at the optimal temperature under normal conditions or in response to chemical treatments, such as GA (Gallardo et al, 2002;Kim et al, 2008), ABA (Kim et al, 2008), and salicylic acid (Rajjou et al, 2006), and environmental stress, such as salinity (Yacoubi et al, 2011(Yacoubi et al, , 2013. To the best of our knowledge, no proteomic study has examined the effect of temperature on seed germination.…”