Salt stress is a major abiotic stress that threatens crop production globally. Among various growth stages, seed germination, crucial for seedling establishment and crop population, is highly sensitive to salt stress. Therefore, it is essential to explore the molecular mechanisms at this stage for the breeding of salt-tolerant crops and global food security. In this study, two salt-tolerant (B080 and B084) and two salt-sensitive (B004 and B005) naked barley landraces were exposed to salt stress for 7 days during germination and their transcriptome were compared to identify differentially expressed genes (DEGs) related to salt stress. In totally, 2348, 1847, 2251, and 1251 DEGs were obtained in B080, B084, B004, and B005, respectively. Then, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment of DEGs were analyzed. Eight DEGs were further validated by qPCR. Although there were only two genes significantly differential expressed, the upregulation and downregulation trends of all genes were consistent with mRNA-seq data. The analysis of DEGs between salt-tolerant and salt-sensitive naked barley landraces under salt stress, as well as their GO and KEGG enrichment, could reveal and enrich the molecular mechanism of salt tolerance in naked barley.

Epichloë endophytes have been found in cool-season grasses and can produce alkaloids that are toxic to vertebrates and insects. Due to their beneficial effects, Epichloë can provide plants with resistance to some abiotic and biotic stresses. The biological and physiological characteristics of the endophytic strains XJE1, XJE2, and XJE3 isolated from wild barley were measured across a range of pH, salt concentrations, and growth values. The phylogenetic position of the Epichloë isolates was examined using the tefA and actG genes. The optimal pH values for mycelial growth of XJE1, XJE2, and XJE3 were 7–8, 6–7, and 8–9, respectively. The isolates grew significantly better at 0.3 mol/L NaCl than at 0.5 mol/L and 0.1 mol/L NaCl. Based on the conidiophore and conidia morphology, growth characteristics, and phylogenetic relationships, the endophyte isolated from wild barley is likely Epichloë bromicola. These isolates exhibited differences in mating types and alkaloid biosynthesis genes. Screening for salt tolerance and alkaloid biosynthetic genes in endophytic strains will provide new insights into useful traits to breed into new forage germplasms.

β-glucan, a crucial trait in barley breeding programs, serves as a quality determinant of products intended for both human consumption and animal feed. Although genes involved in β-glucan synthesis have been reported, the genetic mechanisms regulating its accumulation in barley grain remain underexplored. In this study, we functionally characterized KOB1, a candidate gene identified from a genome-wide association study (GWAS) on barley seed β-glucan content, which encodes a glycosyltransferase. Haplotype analysis showed that haplotype E was associated with significantly elevated grain β-glucan levels compared to other haplotypes. Furthermore, overexpression of KOB1 in rice led to a significant increase in grain β-glucan content relative to the wild-type Zhonghua 11, confirming its critical role in β-glucan biosynthesis. Our findings establish the glycosyltransferase gene KOB1 as a valuable genetic resource for molecular breeding programs aimed at improving grain β-glucan content.

This study investigates the effects of low nitrogen (N) and phosphorus (P) stress on the growth and yield of nine barley (Hordeum vulgare L.) genotypes (1267-2, 1749-1, 1149-3, 2017Y-2, 2017Y-16, 2017Y-17, 2017Y-18, 2017Y-19, and XBZ17-1-61), all of which are spring two-rowed hulled barley types from the Economic Crops and Beer Material Institute, Gansu Academy of Agricultural Sciences. Data were collected over two consecutive growing seasons (2021–2022) at Huangyang Town (altitude 1766 m, irrigated desert soil with 1.71% organic matter, 1.00 g·kg⁻¹ total N, 0.87 g·kg⁻¹ total P in 0–20 cm plough layer) to elucidate the correlation between stress tolerance traits and yield performance. Field experiments were conducted under two treatment conditions: no fertilization (NP0) and normal fertilization (180 kg·hm⁻² N and P, NP180). Growth indicators (plant height, spike length, spikelets per unit area, etc.) and quality indicators (proportion of plump/shrunken grains, 1000-grain weight, protein, starch content) were measured, and data were analyzed using correlation analysis, principal component analysis, and structural equation modeling. The results revealed that low N and P stress significantly impacted quality indicators, such as the proportion of plump and shrunken grains, while having a minimal effect on growth indicators like plant height and spike length. Notably, the number of spikelets per unit area emerged as a critical factor positively influencing yield. Among the tested genotypes, 1749-1, 1267-2, 1149-3, 2017Y-16, 2017Y-18, 2017Y-19, and XBZ17-1-61 exhibited superior yield performance under low N and P stress conditions, indicating their potential for breeding programs focused on stress resilience. Included among these, the 1749-1 line showed the best overall performance and consistent results across both years.