Genomics and domestication of wheat: Modern wheat, which underlies the diet of many across the globe, has a long history of selection and crosses among different species. Avni et al. used the Hi-C method of genome confirmation capture to assemble and annotate the wild allotetraploid wheat ( Triticum turgidum ). They then identified the putative causal mutations in genes controlling shattering (a key domestication trait among cereal crops). They also performed an exome capture–based analysis of domestication among wild and domesticated genotypes of emmer wheat. The findings present a compelling overview of the emmer wheat genome and its usefulness in an agricultural context for understanding traits in modern bread wheat. Science , this issue p. 93

The domestication of wild emmer wheat led to the selection of modern durum wheat, grown mainly for pasta production. We describe the 10.45 gigabase (Gb) assembly of the genome of durum wheat cultivar Svevo. The assembly enabled genome-wide genetic diversity analyses revealing the changes imposed by thousands of years of empirical selection and breeding. Regions exhibiting strong signatures of genetic divergence associated with domestication and breeding were widespread in the genome with several major diversity losses in the pericentromeric regions. A locus on chromosome 5B carries a gene encoding a metal transporter (TdHMA3-B1) with a non-functional variant causing high accumulation of cadmium in grain. The high-cadmium allele, widespread among durum cultivars but undetected in wild emmer accessions, increased in frequency from domesticated emmer to modern durum wheat. The rapid cloning of TdHMA3-B1 rescues a wild beneficial allele and demonstrates the practical use of the Svevo genome for wheat improvement.

To acquire information on the relationships between structural maturation of proteins in the endoplasmic reticulum (ER) and their transport along the secretory pathway, we have analyzed the destiny of an assembly-defective form of the trimeric vacuolar storage glycoprotein phaseolin. In leaves of transgenic tobacco, where assembly-competent phaseolin is correctly targeted to the vacuole, defective phaseolin remains located in the ER or a closely related compartment where it represents a major ligand of the chaperone BiP. Defective phaseolin maintained susceptibility to endoglycosidase H and was slowly degraded by a process that is not inhibited by heat shock or brefeldin A, indicating that degradation does not involve transport along the secretory pathway. These results provide evidence for the presence of a quality control mechanism in the ER of plant cells that avoids intracellular trafficking of severely defective proteins and eventually leads to their degradation.

The postruminal supply of the sulfur-containing amino acids, methionine and cysteine, has been reported to be a major limitation to wool growth in sheep. We aim to improve the protein quality of forage for ruminants by introducing into alfalfa chimeric genes encoding a ruminally stable, sulfur amino acid-rich protein from sunflower seeds. Four gene constructs were transferred to Australian commercial cultivars of alfalfa using Agrobacterium tumefaciens-mediated transformation and selection with phosphinothricin (PPT). Modification of the sunflower seed albumin protein-coding region by addition of the coding information for an endoplasmic reticulum (ER) retention signal was found to greatly increase the level to which the sulfur amino acid-rich protein accumulated in the leaves of transgenic alfalfa plants. The Cauliflower Mosaic Virus (CaMV) 35S promoter and two light-regulated plant gene promoter regions were compared for their ability to direct high-level expression of the introduced genes in alfalfa leaves. The highest expression of sunflower seed albumin was found in transformants bearing a gene incorporating the promoter from the Arabidopsis thaliana ats1A gene, which encodes the ribulose bisphosphate carboxylase small subunit. The highest level of sunflower seed albumin found in transgenic alfalfa leaves was estimated to constitute .1% of soluble leaf protein. This level of accumulation of the foreign protein would be predicted to supply an extra 40 mg of sulfur amino acids daily to sheep fed the modified forage. Published studies in which wool growth rates were significantly increased employed supplementation of approximately 1 to 2 g of sulfur amino acids daily. Copyright © . .

Protein folding in the endoplasmic reticulum (ER) often involves the formation of disulfide bonds. The oxidizing conditions required within this organelle were shown to be maintained through the release of small thiols, mainly cysteine and glutathione. Thiol secretion was stimulated when proteins rich in disulfide bonds were translocated into the ER, and secretion was prevented by the inhibition of protein synthesis. Endogenously generated cysteine and glutathione counteracted thiol-mediated retention in the ER and altered the extracellular redox. The secretion of thiols might link disulfide bond formation in the ER to intra- and intercellular redox signaling.

The growing world population and global increases in the standard of living both result in an increasing demand for food, feed and other plant‐derived products. In the coming years, plant‐based research will be among the major drivers ensuring food security and the expansion of the bio‐based economy. Crop productivity is determined by several factors, including the available physical and agricultural resources, crop management, and the resource use efficiency, quality and intrinsic yield potential of the chosen crop. This review focuses on intrinsic yield potential, since understanding its determinants and their biological basis will allow to maximize the plant's potential in food and energy production. Yield potential is determined by a variety of complex traits that integrate strictly regulated processes and their underlying gene regulatory networks. Due to this inherent complexity, numerous potential targets have been identified that could be exploited to increase crop yield. These encompass diverse metabolic and physical processes at the cellular, organ and canopy level. We present an overview of some of the distinct biological processes considered to be crucial for yield determination that could further be exploited to improve future crop productivity.