The seed proteins of white spruce and their mobilization following germination

Abstract

Buffer‐soluble proteins that have subunit molecular weights, in the presence of sodium dodecyl sulphate (SDS), of 47, 31 and 27 kilodaltons (kDa) form the major storage proteins in the mature white spruce [Picea glauca (Moench) Voss] seed. These proteins were found mainly in the megagametophyte. but smaller amounts were identified in the embryo. Following the completion of germination, this reserve was rapidly hydrolyzed in both tissues and probably plays a major nutritional role in the germinated seed. Buffer‐insoluble proteins were also found in megagametophytes and embryos from the mature seed. These proteins were soluble in buffer only if SDS was present. Predominant in this class of proteins were several that have a subunit molecular weight and structure that is characteristic of seed crystalloid storage proteins; the subunits were shown to be heterodimers with polypeptide molecular weights in the 33 kDa to 37 kDa and 23.5 kDa to 25 kDa ranges. This reserve was rapidly hydrolyzed in the germinated seed. Storage protein hydrolysis was accompanied by a significant increase in the soluble amino acid pool in both megagametophytes and embryos. Cell‐free extracts of mature seed megagametophytes and embryos contained leucine‐naphthylamidase (leuNAase) activity. Following germination. this activity was maintained at a constant level in megagametophytes but increased substantially in embryos.

Embryogeny of gymnosperms: advances in synthetic seed technology of conifers

“…Studies of seed storage proteins of a number of conifer species e.g., Gifford 1988;Gifford & Tolley 1989;Misra & Green 1990;Hakman et al 1990;Flinn et al 1991a;Green et al 1991;Groome et al 1991;Hakman 1993;Leal & Misra 1993a, have shown that conifer protein bodies are composed of a buffer-soluble protein matrix containing water insoluble crystalloid and globoid proteins. The crystalloids are the main storage protein for conifers and their synthesis is developmentally regulated.…”

“…Seed storage proteins are considered to be useful for identifying lineages as they are encoded by multigene families which show considerable homology and appear to have been conserved by evolution (Borroto & Dure 1987). This is demonstrated by the presence of legumin-type proteins in conifers and angiosperms (Gifford & Tolley 1989), and Ginkgo (Jensen & Berthold 1989). Molecular techniques are being increasingly used for determining phylogenetic relationships among plant groups.…”

Storage protein dynamics in zygotic and somatic embryos of white fir

“…At the genera level, A. concolor shared only 43, 22 and 14 kDa major storage proteins with Picea abies Hakman, 1993) and Pinus species (Gofford, 1988) differing from them by its 27 and 24 kDa major proteins in the female gametophyte, as well as by the 24 and 16 kDa components in the embryo. The differences are even more profound in relation to the species Picea glauca (Gifford & Tolley, 1989) and Pinus taeda (Groome et al, 1991).…”

“…The function of storage reserves in Abies seeds is shared by the globulins which were reported to be similar but not identical with soluble proteins of other Pinaceae (Gifford & Tolley, 1989). In Abies, their main components are characterized by the molecular weights of 43, 28 and 16 kDa, respectively, (Jensen & Lixue, 1991) deviating from the corresponding storage protein molecular weight parameters in seeds of Picea abies Hakman, 1993), Picea glauca (Gifford & Tolley, 1989) Pinus species (Gifford, 1988). The seeds of the latter possess three electrophoretically distinguished storage protein components of different molecular masses.…”

Proteolytic enzymes in storage protein mobilization and cell death of the megagametophyte of Araucaria bidwillii Hook. post-germinated seeds

“…A partial characterization of some proteolytic activities during germination of Pinus sylvestris seeds (Salmia et al 1978), suggested that the bulk of storage protein mobilization was carried out by the sulfydrilic enzymes proteinase I and II, with smaller contributions by pepstain-sensitive proteinase(s), acid carboxypeptidase(s) and naphtylamidase(s) (Salmia and Mikola 1976a, b). The presence of amino-and carboxypeptidase activities in Pinus contorta and Picea glauca germinated seeds with a possible involvement in the storage protein mobilization, has been demonstrated Gifford and Tolley 1989).…”