Expression of Storage Protein Genes in Developing Wheat (Triticum aestivum L.) Seeds

Abstract

Ribonucleic acid and protein synthesis in developing wheat kernels have been studied through in vivo labeling of wheat heads in culture. In INIA 66R wheat labeled with 15-'Hluridine for 24-hour periods between 9 and 33 days after flowering, the total rate of RNA accumulation in endosperm/ testa pericarp tissues was highest in the youngest seeds, and declined with increasing seed age. In contrast, the rate of accumulation of po1y (A) events related to the initiation and duration of mRNA synthesis, the efficiency of mRNA translation, and the operational stability of mRNA in the cell are important as determinants of yield because they influence the ability ofthe seed to accumulate reserve materials. They also constitute an attractive system for the study of differentiation and of regulation of gene expression.Storage protein synthesis in cereals continues over an extended time period, and it is of interest to identify factors that facilitate this. Developmental studies of cereal seeds have included investigations of in vitro protein synthesis capacity of maize endosperm polysomes (15, 24), protein (7) and nucleic acid synthesis (28) in wheat, and nucleic acid synthesis in sorghum (14), but the synthesis and stability of mRNA have not been extensively examined, and most relevant observations have been made on legume seeds (10,22,23). This report examines RNA and protein synthesis as functions of development in the wheat kernal via in vivo labeling of RNA and protein of developing wheat kernels, and in vitro translation of kernel RNA. Evidence is presented that wheat storage protein mRNAs are long-lived species, and it is concluded that mRNA transcription and persistence are controlling factors in the synthesis of storage proteins. MATERIALS AND METHODSReagents. Radiochemicals were purchased from New England Nuclear.2 Boston, Mass. Agarose poly(U), type 6 was purchased from P-L Biochemicals, Milwaukee, WI. Wheat germ was a generous gift of Herbert Sanguinetti, General Mills, Inc., Vallejo, CA. SDS (specially purified) was purchased from Gallard-Schlesinger Corp., Carle Place, NY. Other biochemical reagents were purchased from Sigma, Calbiochem-Behring, or

Genomic regions influencing gene expression of the HMW glutenins in wheat

“…In a previous study, Wanous et al (2003) showed chromosomes 1BL and 1DL had the most significant effects on Glu-B1 and Glu-D1 protein expression. The corresponding results of these studies and a preceding investigation by Greene (1983) suggest HMW glutenin RNA transcript levels predict the final protein concentration and confirm the consistency and reliability of ditelosomic genetic stocks for expression analysis. The HMW glutenin genes shared effects of putative regulatory loci on groups B and D, based on strong correlations of expression effects of group B and D chromosome arms.…”

Gene Expression in Developing Wheat Endosperm

“…On SDS polyacrylamide gels, the purified y-gliadin fraction ipea chlorotic mottle virus RNA (gift of Dr. S. D. gave two bands with mol wt of 41 and 37 kD, while the a/fl-J). SDS-PAGE of the in vitro translation products gliadin fraction gave major and minor bands of 34 and 31 kD, similar to those of Greene (8). The putative gliadin respectively.…”

“…Although gliadin mRNAs accumulate early in the middle phase of endosperm development (8), it is not clear whether the individual genes are coordinately or differentially expressed. We have recently characterized the sequence diversity of the a/fl-and y- ' Supported by Grants type gliadin gene subfamilies which encode most of the gliadin polypeptides (19).…”

Regulation of Protein Synthesis in Plant Embryo by Protein Phosphorylation

“…It is known that after fertilization, the synthesis of RNA and protein is quite high during the first 15 d and slows down thereafter (8). Seeds reach a maximum weight by the 30th d after which they dehydrate.…”