Whats left from the brew? Investigating residual barley proteins in spent grains for downstream valorization opportunities
Authors: Gregersen Echers, S., Mikkelsen, R. K., Abdul-Khalek, N., Queiroz, L. S., Hobley, T. J., Schulz, B. L., Overgaard, M. T., Jacobsen, C., Yesiltas, B.
The study provides an in‑depth proteomic characterization of brewer's spent grain (BSG) and tracks proteome dynamics during malting and mashing, revealing that 29% of identified proteins change in abundance and that B3‑Hordein dominates the BSG protein pool. BSG contains a high proportion of intracellular proteins and over 45% of its proteins are potential allergens or antinutritional factors, underscoring the need for targeted downstream processing to create safe, functional food ingredients.
The study generated a high-quality genome assembly for Victoria cruziana and used comparative transcriptomics to identify anthocyanin biosynthesis genes and their transcriptional regulators that are differentially expressed between white and light pinkish flower stages. Differential expression of structural genes (VcrF3H, VcrF35H, VcrDFR, VcrANS, VcrarGST) and transcription factors (VcrMYB123, VcrMYB-SG6_a, VcrMYB-SG6_b, VcrTT8, VcrTTG1) correlates with the observed flower color change.
The study demonstrates that RNA extracted from herbarium specimens can be used to generate high‑quality transcriptomes, comparable to those from fresh or silica‑dried samples. By assembling and comparing transcriptomes across specimen types, the authors validated a plant immune receptor synthesized from a 1956 collection, proving archival RNA’s utility for functional genomics. These findings challenge the prevailing view that herbarium RNA is unsuitable for transcriptomic analyses.
The study profiled the Arabidopsis apoplastic proteome during pattern‑triggered immunity induced by the flg22 peptide, using apoplastic washing fluid with minimal cytoplasmic contamination followed by LC‑MS/MS. Results showed consistent PTI‑specific enrichment and depletion of peptides, a bias toward ectodomain peptides of receptor‑like kinases, and increased abundance of the exosome marker tetraspanin 8, indicating heightened exosome levels during PTI.
The study investigated unexpected leaf spot symptoms in Psa3‑resistant kiwifruit (Actinidia) germplasm, finding that Psa3 was detectable by qPCR and metabarcoding despite poor culturing. Metabarcoding revealed distinct bacterial community shifts in lesions versus healthy tissue, and whole‑genome sequencing identified diverse Pseudomonas spp. that, while not individually more pathogenic, could enhance Psa3 growth, suggesting pathogenic consortia on resistant hosts.