An interolog-based barley interactome as an integration framework for immune signaling

The barley MLA nucleotide-binding, leucine-rich-repeat (NLR) receptor and its orthologs confer recognition specificity to many cereal diseases, including powdery mildew, stem and stripe rust, Victoria blight, and rice blast. We used interolog inference to construct a barley protein interactome (HvInt) comprising 66133 edges and 7181 nodes, as a foundation to explore signaling networks associated with MLA. HvInt was compared to the experimentally validated Arabidopsis interactome of 11253 proteins and 73960 interactions, verifying that the two networks share scale-free properties, including a power-law distribution and small-world network. Then, by successive layering of defense-specific 'omics' datasets, HvInt was customized to model cellular response to powdery mildew infection. Integration of HvInt with expression quantitative trait loci (eQTL) enabled us to infer disease modules and responses associated with fungal penetration and haustorial development. Next, using HvInt and an infection-time-course transcriptome, we assembled resistant (R) and susceptible (S) subnetworks. The resulting differentially co-expressed (R-S) interactome is essential to barley immunity, facilitates the flow of signaling pathways and is linked to Mla through trans eQTL associations. Lastly, next-generation, yeast-two-hybrid screens identified fifteen novel MLA interactors, which were incorporated into HvInt, to predict receptor localization, and signaling response. These results link genomic, transcriptomic, and physical interactions during MLA-specified immunity.

Barley Protein Properties, Extraction and Applications, with a Focus on Brewers’ Spent Grain Protein

Barley is the most commonly used grain in the brewing industry for the production of beer-type beverages. This review will explore the extraction and application of proteins from barley, particularly those from brewers’ spent grain, as well as describing the variety of proteins present. As brewers’ spent grain is the most voluminous by-product of the brewing industry, the valorisation and utilisation of spent grain protein is of great interest in terms of sustainability, although at present, BSG is mainly sold cheaply for use in animal feed formulations. There is an ongoing global effort to minimise processing waste and increase up-cycling of processing side-streams. However, sustainability in the brewing industry is complex, with an innate need for a large volume of resources such as water and energy. In addition to this, large volumes of a by-product are produced at nearly every step of the process. The extraction and characterisation of proteins from BSG is of great interest due to the high protein quality and the potential for a wide variety of applications, including foods for human consumption such as bread, biscuits and snack-type products.

Impact of Ultrasound Treatment and pH-Shifting on Physicochemical Properties of Protein-Enriched Barley Fraction and Barley Protein Isolate

Ultrasonication alone or in combination with a pH-shifting method could be applied as means for improving the techno-functional properties and performance of barley protein ingredients in liquid food matrix. Ultrasound technology was utilised with and without pH-shifting to 3, 7 and 9 aiming at investigating their impact on primary protein structure, protein solubility, particle size and colloidal stability of an air-classified protein-enriched barley fraction and a barley protein isolate. Shifting the pH of sample dispersion to 9 followed by neutralisation to pH 7 improved protein solubility and colloidal stability of the isolate whereas it had less impact on the protein-enriched fraction. Ultrasound treatment improved both protein solubility and colloidal stability of the protein-enriched fraction at alkaline pH and particle size reduction by ultrasonication was observed at all the studied pH-values. For protein isolate, ultrasonication improved protein solubility at all pH-values and colloidal stability was improved at acidic and neutral pH whereas the sample was inherently stable at alkaline pH. The protein profiles of both ingredients remained unaffected by ultrasound treatment. The results suggest adopting ultrasonication as a promising tool for improving applicability of barley protein ingredients in liquid food systems.

Mutation of the ALBOSTRIANS Ohnologous Gene HvCMF3 Impairs Chloroplast Development and Thylakoid Architecture in Barley due to Reduced Plastid Translation

ABSTRACTGene pairs resulting from whole genome duplication (WGD), so-called ohnologous genes, are retained only if at least one gene of the pair undergoes neo- or subfunctionalization. Sequence-based phylogenetic analyses of the ohnologous genes ALBOSTRIANS (HvAST/HvCMF7) and ALBOSTRIANS-LIKE (HvASL/HvCMF3) of barley (Hordeum vulgare) revealed that they belong to a newly identified subfamily of genes encoding CCT domain proteins with putative N-terminal chloroplast transit peptides. Recently, we showed that HvCMF7 is needed for chloroplast ribosome biogenesis. Here we demonstrate that mutations in HvCMF3 lead to seedlings delayed in development. They exhibit a xantha phenotype and successively develop pale green leaves. Compared to the wild type, plastids of the mutant seedlings show decreased PSII efficiency and lower amounts of ribosomal RNAs; they contain less thylakoids and grana with a higher number of more loosely stacked thylakoid membranes. Site-directed mutagenesis of HvCMF3 identified a previously unknown functional region, which is highly conserved within this subfamily of CCT domain containing proteins. HvCMF3:GFP fusion constructs localized to plastids. Hvcmf3Hvcmf7 double mutants indicated epistatic activity of HvCMF7 over HvCMF3. The chloroplast ribosome deficiency is discussed as the primary defect of the Hvcmf3 mutants. Our data suggests that HvCMF3 and HvCMF7 have similar but not identical functions.One-sentence summaryPhylogenetic and mutant analyses of the barley protein HvCMF3 (ALBOSTRIANS-LIKE) identified, in higher plants, a subfamily of CCT domain proteins with essential function in chloroplast development.