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

Abstract

Abstract Key message Adequate storability of black poplar (Populus nigraL.) seeds at temperatures below 0 °C was associated with preservation of proteins of energy and carbohydrate metabolism, protein turnover, and proteins maintaining long-term 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.