Proteomic analysis of black poplar (Populus nigra L.) seed storability

Abstract

& Key message Adequate storability of black poplar (Populus nigra L.) seeds at temperatures below 0°C was associated with preservation of proteins of energy and carbohydrate metabolism, protein turnover, and proteins maintaining longterm stability of dehydrated tissue. & Context Understanding seed storability is a key factor for effective seed preservation and conservation. Black poplar is an endangered tree species and its seed loses rapidly viability during storage. & Aims The aim of this study was to determine, and functionally characterise, the proteins associated with storability of black poplar seeds. & Methods Dried seeds (7.1% MC) were stored at 3°C, − 3°C, − 20°C, and − 196°C, for a period of 12 and 24 months. Proteins were extracted and separated according to their isoelectric point (pI) and mass using 2-dimensional electrophoresis. Proteins that varied in abundance for temperature and time of storage were identified by mass spectrometry. & Results A germination test showed that seeds remained viable at − 3, − 20, and − 196°C. Storage at 3°C caused loss of seed viability. This loss in seed vigour was related to the largest changes in protein abundance. As storage temperature decreased, a smaller number of proteins displayed changed abundance. & Conclusion Good storability of black poplar seeds under freezing conditions may be associated with the following: an inhibition of synthesis of energy and carbohydrate metabolism and protein turnover proteins, LEA proteins that maintain long-term stability of dehydrated tissue, GDSL esterases/lipases that inhibit hydrolysing activity, and by chaperonins that protect protein functionality. Storage conditions influence the preservation of protein function that governs seed viability.

Variability in seeds’ physicochemical characteristics, germination and seedling growth within and between two French Populus nigra L. populations

“…As the weight of a seed is linked to the energy reserves available as an embryo develops into a seedling, it seems reasonable to assume that a difference in mass should lead to a difference in vigour, and that seeds' sizes should correlate with their survival rates. However, the relationships are highly taxon-dependent, as demonstrated by previously reported positive and negative correlations between these parameters (González-Rodríguez et al, 2012;Rajjou et al, 2012;Zhang et al, 2015;Ghaffaripour et al, 2017;Wang et al, 2018). We observed no significant differences in three consecutive years in seedlings' germination rates, between either families or populations.…”

“…seeds has negative consequences for breeding and genetic conservation programs (Muller et al, 1982;Stanton & Villar, 1996). Hence, attempts have been recently made to address these problems and identify optimum protocols for ex situ seed conservation (Suszka et al, 2014;Michalak et al, 2015;Pawłowski et al, 2019). Following demonstrations that they can be stored up to several years in specific conditions, seeds of the species have been re-classified as intermediate between orthodox seeds, which can withstand dehydration to water contents as low as 50 mg.g -1 (Roberts, 1973), and recalcitrant seeds (Bonner, 2008;Suszka et al, 2014;Michalak et al, 2015).…”

Seed integrity, effect of temperature and storage time on germination of <em>Populus luziarum</em> and <em>P. primaveralepensis</em>, endangered subtropical species from Mexico

“…Bonner (2008) and Pritchard & Nadarajan (2008) mentions that seeds can be kept viable for several years, when stored at sub-zero temperatures and in a dry atmosphere. For future research, we suggest to include treatments at temperatures below 0 °C and cryopreservation for more promising ex situ seed conservation of these species (Suszka et al 2014), as it has been shown that these techniques could obtain favorable results in longevity and maintain viability for longer periods (Pawłowski et al 2019).…”

Regulation of Seed Dormancy and Germination Mechanisms in a Changing Environment

“…The environmental variability (seasonality) is crucial to explaining the existence or absence of dormancy and evolutionary transitions between these states [ 46 ]. In addition to the genetic background of this adaptation, environmental factors can shape the depth of dormancy and seed germination [ 8 , 47 ]. Models developed for climate change scenarios show that many species would face a significant decrease in suitable habitat area [ 48 ], also because of disturbances in the reproduction process ( Figure 1 ).…”