Regulation Of Storage Protein Synthesis Research Articles

Mutants at gliadin loci on the basis of the common wheat cultivar Bezostaya 1

Aim. The aim of this study was to isolate and propagate mutants at gliadin loci developed on the basis of the common wheat cultivar Bezostaya 1. Methods. We searched for spontaneous and gamma-irradiation induced mutations at gliadin loci among the progeny of F1 and F2 plants from crosses between near-isogenic lines by gliadin loci on the basis of the cultivar Bezostaya 1, including lines with the wheat-rye 1BL.1RS translocation. To identify mutations, we performed acid polyacrylamide gel electrophoresis and SDS-electrophoresis of storage proteins. Results. On the basis of the common wheat cultivar Bezostaya 1, five mutants (six mutations) at gliadin loci were isolated and propagated, four of which were described for the first time. Three mutations occurred at the Gli-R1 locus involved in the wheat-rye 1BL.1RS translocation (the loss of secalins, intensification of a secalin component, and increased mobility of a secalin component). Two mutations were identified in the allele Gli-B1b, one caused the null-allele at the Gli-A2 locus. Conclusions. The material of mutants is of importance for studying the role of certain groups of storage proteins and their components in quality determination, as well as mechanisms of regulation of storage protein synthesis.
 Keywords: Triticum aestivum, gliadin, secalin, mutation, 1BL.1RS translocation.

Transcriptional Regulation of Storage Protein Synthesis During Dicotyledon Seed Filling

Seeds represent a major source of nutrients for human and animal livestock diets. The nutritive value of seeds is largely due to storage products which accumulate during a key phase of seed development, seed filling. In recent years, our understanding of the mechanisms regulating seed filling has advanced significantly due to the diversity of experimental approaches used. This review summarizes recent findings related to transcription factors that regulate seed storage protein accumulation. A framework for the regulation of storage protein synthesis is established which incorporates the events before, during and after seed storage protein synthesis. The transcriptional control of storage protein synthesis is accompanied by physiological and environmental controls, notably through the action of plant hormones and other intermediary metabolites. Finally, recent post-genomics analyses on different model plants have established the existence of a conserved seed filling process involving the master regulators (LEC1, LEC2, ABI3 and FUS3) but also revealed certain differences in fine regulation between plant families.

Developmental-regulation and tissue-specific expression of two different seed promoter GUS-fusions in transgenic lines of Vicia narbonensis

Summary Two different promoter/GUS fusions driven either by the leguminB4 promoter (leB4) or the promoter of the unknown seed protein (usp) from Vicia faba were introduced into Vicia narbonensis to study the regulation and the activity of seed specific promoters under homologous conditions. For each construct two lines with a single copy insertion of the T-DNA were propagated and subjected to further analysis. Hemi- and homozygous subpopulations were produced up to the sixth generation and the amount of β-glucuronidase as well as the course of transcript accumulation of GUS mRNA and several seed protein mRNAs were determined during seed development. Quantitative GUS assays revealed a correlation between GUS accumulation and the allelic state of the plants (hemWhomozygous for the transgene). The two lines expressing the usp-GUS fusion showed GUS activity from the globular stage of seed development (day 5 to 7 after pollination), whereas in lines containing the leB4-GUS fusion, the GUS expression and transcript accumulation started at the mid-cotyledon stage (approx. 15 DAP). In one of the two leB4-GUS lines GUS expression was not restricted to the embryo exclusively, activity was also found in the seed coat. The expression of the GUS gene driven by the two seed specific promoters in Vicia narbonensis is very similar to that which has been reported on the developmental expression of the original genes in Vicia faba . The transgenic lines generated in the present study are useful tools for examining the functions, the mechanisms, and the regulation of storage protein synthesis.

Regulation of Storage Protein Synthesis in Cereal Seeds: Developmental and Nutritional Aspects

Summary The major seed storage proteins of cereals are deposited in the maturation phase of endosperm development, starting at 12 days after pollination (dap) in maize and continuing up to around 30dap. Cell types-pecific expression in the endosperm is conferred by a multicomponent promoter motif, the endosperm box sequence. Proteins interacting at this motif include the gene product of the regulatory gene Opaque-2 (O2). O2 encodes a b2IP transcription factor, which is capable of activating its target promoters, 22kD α-zein and b-32, in a number of experimental systems. Storage protein accumulation, and storage protein promoter activity, are modulated according to available levels of nitrogen (N). In barley, nitrogen regulation is mediated by the endosperm box via interaction of the endosperm and GCN 4 motifs. The nitrogen- responsive components of the 22kd zein promoter have been shown to include the O2-binding sites Z1–Z3 but to display N-responsiveness even in the absence of O2 protein.

Temporal and nutritional factors modulate responses to abscisic acid and osmoticum in their regulation of storage protein synthesis in developing seeds of alfalfa (Medicago sativaL.)

Storage protein synthesis during alfalfa (Medicago saliva L.) seed development displays a temporal pattern and is regulated both by ABA and low osmotic potentials. Deposition of the 2S, 7S and 11S storage proteins occurs maximally at the mid- to late stages of development. Osmoticum, but not ABA alone could effectively induce storage protein synthesis at early stages of development in isolated alfalfa embryos placed on water for several days. Neither ABA nor osmoticum alone could maintain storage protein synthesis in isolated late-stage embryos placed on water. On the other hand, isolated developing embryos cultured on a nutrient (Murashige and Skoog) medium could maintain storage protein synthesis in the presence of ABA and osmoticum, alone or in combination, for up to 14 d after being dissected from the pod. Of the components of this medium, the inorganic salts appeared to be the most important. The response to ABA and osmoticum varied with the time of isolation during development with the greatest enhancement of storage protein synthesis in isolated embryos coinciding with the time of maximum synthesis within the seed when in planta. Addition of ABA and osmoticum after the time of maximum storage protein synthesis did not elevate the amount of synthesis, but rather prolonged the time over which it could take place. Thus, while the amplitude of storage protein synthesis could be modified by ABA or osmoticum, the inherent temporal pattern, with maximum synthesis occurring only at mid- to late stages of embryo development, could not

Regulation of storage protein synthesis by nitrogen and sulfur nutrients in alfalfa ( Medicago sativa L.) somatic embryos

The low vigor of seedlings from dry somatic embryos of alfalfa ( Medicago sativa L.) limits the establishment of plants from artificial seeds. slow growth and development may be associated with low storage protein deposition in the somatic embryo. The nutritional regulation of storage protein accumulation by nitrogen and sulfur nutrients was investigated to improve ultimately the vigor of dry somatic embryos. All somatic embryos were induced from petiole explants on 2,4-dichlorophenoxyacetic acid-containing medium, dispersed in a suspension, sieved, and developed to the torpedo stage before application of the treatments. During the period of reserve deposition (phase I maturation), different forms and levels of nitrogen and sulfur nutrients were supplied. Subsequently, all somatic embryos were matured on phase II maturation medium for induction of desiccation tolerance, and then dried at a relative humidity of 43%. Somatic embryo quality was assessed by germination (root elongation) and conversion (root and leaf development) after imbibition on moist filter paper. The addition of 50 mM glutamine to the maturation medium prior to autoclaving enhanced accumulation of the sulfur-poor 7S alfin and 11S medicagin storage proteins. Autoclaving the medium converted glutamine to pyroglutamic acid (5-oxoproline) and ammonia. Addition of these end-products simulated the autoclaved-glutamine effect, whereas filter-sterilized glutamine promoted cell expansion and precocious germination. The addition of inorganic sulfates (10–25 mM) increased the accumulation of the sulfur-rich 2S storage proteins and the B 1 and B 2 subunits of the 11S medicagin. The combination of pyroglutamic acid, ammonium and sulfate in the maturation phase I medium dramatically increased accumulation of the 2S proteins and all subunits of the 11S medicagin. Application of ammonium nitrate as the major inorganic nitrogen source did not replace the requirement for pyroglutamic acid. The results indicate that pyroglutamic acid, ammonia and sulfate had nutritive and regulatory roles in storage protein accumulation. The increased accumulation of storage proteins, especially low molecular weight 2S and 11S medicagin, was correlated positively with quality of somatic embryos. The sulfur nutrients had an additional unexpected effect. Somatic embryos that were matured on high sulfate containing media were unable to germinate unless they were desiccated, indicating some form of metabolically-imposed quiescence. This confirms that sulfate has an important regulatory role in somatic embryo development.

Regulation of storage-protein synthesis in pea (Pisum sativum L.) cotyledons under conditions of sulphur deficiency

The effects of sulphur deficiency on the expression of storage-protein genes in developing pea (Pisum sativum) cotyledons were studied. Legumin-gene transcription was decreased by S-deficiency, but not to the same extent as the decrease in the level of legumin mRNA. Vicilin-gene transcription was not significantly affected. Control of gene expression may thus occur during transcription and/or post-transcriptional events.

Regulation of Storage Protein Synthesis by Sulphur and Nitrogen Nutrition in Cultured Immature Caryopses of Barley

Regulation of Storage Protein Synthesis by Sulphur and Nitrogen Nutrition in Cultured Immature Caryopses of Barley

Developmental and sex-dependent regulation of storage protein synthesis in the silkworm, Bombyx mori

The mechanism of sex-dependent expression of a major plasma protein, referred to as storage protein 1 (SP-1) was studied during development of the silkworm, Bombyx mori. SP-1 occurred in the hemolymph of the female as well as in the male larvae until the end of the fourth larval instar. In the last instar larvae, the amount of SP-1 in the hemolymph greatly increased in females, but markedly declined in males. The level of fat body mRNA for SP-1 reflected the developmental and sex-dependent changes in the hemolymph concentration of SP-1. The developmental patterns of hemolymph proteins in the third and the fourth instar larvae of sex-mosaic individuals were quite analogous to those observed in normal larvae at the same developmental stages. The hemolymph concentration of SP-1 at the last larval instar of the sex mosaics varied among individuals irrespective of the gonad compositions. In vitro culture of the fat body cells dissected from several locations of a sex-mosaic larva provided evidence that each fat body cell in a common hemolymph milieu synthesizes a high (female type) or a low (male type) level of SP-1 depending on the sex chromosome composition. The amount of vitellogenin in the hemolymph of the sex-mosaic pupae was in proportion to that of SP-1 at the last larval instar. From these results, it is suggested that the sex-dependent expression of SP-1 and vitellogenin in B. mori is genetically determined and developmentally regulated without participation of the reproductive organs or any sex-specific humoral factors.