Lipidomics studies reveal dynamic changes in polar lipids of developing endosperm of oat and wheat varieties with differing oil contents

Polar lipids have biosynthetic pathways which intersect and overlap with triacylglycerol biosynthesis; however, polar lipids have not been well characterized in the developing endosperms of oat with high oil accumulation. The polar lipids in endosperms of oat and wheat varieties having different oil contents were analyzed and compared at different developmental stages. Our study shows that the relative contents of polar lipid by mass were decreased more slowly in wheat than in oat. Phosphatidylcholine and phosphatidylethanolamine were the major phospholipids, which showed similar abundance and gradual decreases during endosperm development in oat and wheat, while lysophospholipids were noticeably higher in oat. Monogalactosyldiacylglycerol showed a gradual increase in wheat and a decrease in oat during endosperm development. The relative contents of some polar lipid species and their unsaturation index were significantly different in their endosperms. These characteristics of polar lipids might indicate an adaption of oat to accommodate oil accumulation.

Large flour aggregates containing ordered B + V starch crystals significantly improved the digestion resistance of starch in pretreated multigrain flour

The starch digestibility of flour is influenced by both physicochemical treatment and flour particle size, but the interactive effect of these two factors is still unclear. In this study, the effect of pullulanase debranching, combined with heat-moisture treatment (P-HMT), on starch digestibility of multi-grain flours (including oat, buckwheat and wheat) differing in particle size was investigated. The results showed that the larger-size flour always resulted in a higher resistant starch (RS) content either in natural or treated multi-grain flour (NMF or PHF). P-HMT doubled the RS content in NMFs and the large-size PHF yielded the highest RS content (78.43 %). In NMFs, the cell wall integrity and flour particle size were positively related to starch anti-digestibility. P-HMT caused the destruction of cell walls and starch granules, as well as the formation of rigid flour aggregates with B + V starch crystallite. The largest flour aggregates with the most ordered B + V starch were found in large-size PHF, which contributed to its highest RS yield, while the medium- and small-size PHFs with smaller aggregates were sensitive to P-HMT, resulting in the lower ordered starch but stronger interactions between starch and free lipid or monomeric proteins, eventually leading to their lower RS but higher SDS yield.

Comparison of the anti-diabetic effects of various grain and legume extracts in high-fat diet and streptozotocin-nicotinamide-induced diabetic rats

The anti-diabetic properties of whole groats and dietary fibers from various grains and legumes are well known. Nevertheless, studies on the anti-diabetic effects of their extracts are limited, and it is difficult to compare their efficacy. This study investigated the anti-diabetic potential of ethanol extracts from oats (OE), sorghum (SE), foxtail millet (FE), proso millet (PE), adzuki bean (AE), and black soybean (BE) in a high-fat diet and streptozotocin-nicotinamide-induced diabetic rat models. The extracts, obtained using 99.9 % ethanol, were orally administered to diabetic rats for four weeks. Various parameters were evaluated, including fasting blood glucose levels, glucose tolerance, insulin sensitivity, serum insulin levels, and pancreas histological analysis. OE and SE effectively reduced fasting blood glucose levels and the area under the curve (AUC) in the oral glucose tolerance test. Only OE significantly decreased the AUC in the insulin tolerance test and increased insulin concentration and homeostatic model assessment of the β-cell function index, indicating improved insulin sensitivity and β-cell function. Histological and immunohistochemical analysis of the pancreas supported these findings, demonstrating that OE protected against pancreatic cell damage. In contrast, FE, PE, AE, and BE did not have a significant effect on diabetes-related parameters. These findings identify OE as the most promising natural intervention for diabetes management.

Sodium doping and trapped ion mobility spectrometry improve lipid detection for novel MALDI-MSI analysis of oats

Oat (Avena sativa L.) is an important cereal grain with a unique nutritional profile including a high proportion of lipids. Understanding lipid composition and distribution in oats is valuable for plant, food and nutritional research, and can be achieved using MALDI mass spectrometry imaging (MALDI-MSI). However, this approach presents several challenges for sample preparation (hardness of grains) and analysis (isobaric and isomeric properties of lipids). Here, oat sections were successfully mounted onto gelatin-coated indium tin oxide slides with minimal tearing. Poor detection of triacylglycerols was resolved by applying sodium chloride during mounting, increasing signal intensity. In combination with trapped ion mobility spectrometry (TIMS), lipid identification significantly improved, and we report the separation of several isobaric and isomeric lipids with visualisation of their "true" spatial distributions. This study describes a novel MALDI-TIMS-MSI analytical technique for oat lipids, which may be used to improve the discovery of biomarkers for grain quality.

The pleiotropic role of Salinicoccus bacteria in enhancing ROS homeostasis and detoxification metabolism in soybean and oat to cope with pollution of triclosan

Triclosan has been extensively used as a preservative in cosmetics and personal care products. However, its accumulation represents a real environmental threat. Thus, its phytotoxic impact needs more consideration. Our study was conducted to highlight the phytotoxic effect of triclosan on the growth, ROS homeostasis, and detoxification metabolism of two different plant species i.e., legumes (Glycine max) and grass (Avena sativa). Moreover, we investigated the potentiality of plant growth-promoting bacteria (ST-PGPB) in mitigating the phytotoxic effect of triclosan. Triclosan induced biomass (fresh and dry weights) reduction in both plants, but to a higher extent in oats. This decline was associated with a noticeable increment in the oxidative damage (e.g., MDA and H2O2) and detoxification metabolites such as metallothionein (MTC), phytochelatins (PCs), and glutathione-S-transferase (GST). This elevation was associated with a remarkable reduction in both enzymatic and non-enzymatic antioxidants. On the other hand, the bioactive strain of ST-PGPB, Salinicoccus sp. JzA1 significantly alleviated the harmful effect of triclosan on both soybean and oat plants by enhancing their biomass, photosynthesis, as well as levels of minerals (K, Ca, P, Mn, and Zn). In parallel, a striking quenching in oxidative damage and an obvious improvement in non-enzymatic (polyphenols, tocopherols, flavonoids) and enzymatic antioxidants were observed. Furthermore, Salinicoccus sp. JzA1 augmented the detoxification metabolism by enhancing the levels of phytochelatins, metallothionein, and glutathione-S-transferase (GST) activity in a species-specific manner which is more apparent in soybean rather than in oat plants. To this end, stress mitigating impact of Salinicoccus sp. JzA1 provides a basis to improve the resilience of crop species under cosmetics and personal care products toxicity.

Genome-wide identification and functional analysis of the cellulose synthase-like gene superfamily in common oat (Avena sativa L.)

Hemicelluloses constitute approximately one-third of the plant cell wall and can be used as a dietary fiber and food additive, and as raw materials for biofuels. Although genes involved in hemicelluloses synthesis have been investigated in some model plants, no comprehensive analysis has been conducted in common oat at present. In this study, we identified and systematically analyzed the cellulose synthase-like gene (Csl) family members in common oat and investigated them using various bioinformatics tools. The results showed that there are 76 members of the oat Csl gene family distributed on 17 chromosomes, and phylogenetic analysis indicated that the 76 Csl genes belong to the CslA, CslC, CslD, CslE, CslF, CslH, and CslJ subfamilies. A total of 14 classes of cis-acting elements were identified in the promoter regions, including hormone response, light response, cell development, and defense stress elements. The collinearity analysis identified 28 pairs of segmentally duplicated genes, most of which were found on chromosomes 2D and 6A. Expression pattern analysis showed that oat Csl genes display strong tissue-specific expression; of the 76 Csl genes, 33 were significantly up-regulated in stems and 30 were up-regulated in immature seeds. The expression of most members of the AsCsl gene family is repressed by abiotic stress, while the expression of some members is up-regulated by light. Immunoelectron microscopy shows that the product of AsCsl61, a member of CslF subfamily, mediates (1,3; 1,4)-β-D-glucan synthesis in transgenic Arabidopsis. These findings provide a fundamental understanding of the structural, functional, and evolutionary features of the oat Csl genes and may contribute to our general understanding of hemicellulose biosynthesis. Moreover, this information will be helpful in designing experiments for genetic manipulation of mixed-linkage glucan (MLG) synthesis with the goal of quality improvement in oat.

Phylogenetic analysis of Microdochium spp. associated with turfgrass and their pathogenicity in cereals

Turfgrass is frequently used today in the arrangement and aesthetic beautification of grounds in parks, gardens, median strips, recreation and sports areas. In this study, surveys were conduct in turfgrass areas in the three provinces of Türkiye. As a result of isolations from the collected samples, 44 Microdochium isolates obtained belonging to five different species including M. bolleyi, M. majus, M. nivale, M. paspali and M. sorghi which have different virulences. Identification of the isolates were performed by rDNA-ITS sequence analyzes. According to the pathogenicity tests results, the most virulent species was M. nivale M62 with a disease severity value of 91.93%. This was followed by M. bolleyi M1584 and M. majus M63, with disease severity values of 91.12% and 91.08%, respectively. The virulence of M. bolleyi isolates varied among the species. Only 13 of the 31 M. bolleyi species were found to be virulent in turfgrass, M. paspali was less virulent than the others in Poa pratensis. The most virulent isolate of each Microdochium species was tested on four different cereal varieties. M. sorghi and M. paspali had low virulence values in barley and oat than the other Microdochium species, while the other three species showed high virulence in turfgrass, wheat and barley, other than oat. In the phylogenetic neighboor-joining tree belonging to 44 Microdochium isolates clearly demonstrated that the isolates were grouped into five distinct clusters. M. nivale and M. majus were considered genetically close isolates.

Starch of oat derived nanostructured Fe/Mn bimetallic carbon materials for sulfamethoxazole degradation via peroxymonosulfate activation

Fe/Mn bimetallic carbon materials were synthesized by combining oat and urea, followed by and carbonization processes, the activity and mechanism of the obtained materials in activating peroxymonosulfate (PMS) for sulfamethoxazole (SMX) degradation were determined. Data suggested that the obtained material (CN@FeMn-10-800) showed the optimal performance for SMX degradation under the1:8:0.05:0.05 mass ratios of oat/urea/Fe/Mn. Around 91.2 % SMX (10 mg L-1) was removed under the conditions of 0.15 g L-1 CN@FeMn-10-800 and 0.20 g L-1 PMS. The CN@FeMn-10-800 showed great adaptability under different conditions, satisfactory activation repeatability and versatility. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) demonstrated that core-shell structure with rich porous of CN@FeMn-10-800 was achieved. Quenching test and electron paramagnetic resonance (EPR) indicated that surface bound oxygen and singlet oxygen (1O2) were the dominate reactive groups in this system. X-ray photoelectron spectroscopy (XPS) suggested that graphite N, Fe0, Fe3C and Mn(II) were the dominant active sites. Through the work, a simple strategy could be found to make high-value use of biomass and use it to effectively purified wastewater.

Influence of 10 MeV electron beam irradiation on the lipid stability of oat and barley during storage

This study investigated the effect of electron beam irradiation (EBI) on the lipid stability of oat and barley during long-term storage. Results showed that the initial free fatty acid content in oat was higher than that in barley. This may mean that lipid hydrolysis started under the function of lipase when oat and barley were milled into flours. Both storage and EBI factors influenced lipid-degrading enzyme activity and promoted lipid oxidation in oat and barley. However, it seemed that storage had higher impacts because the DPPH scavenging activity decreased greatly, and the contents of both malondialdehyde and volatile lipid oxidation products increased in all samples. Thus, the antioxidant capacity and level of lipid oxidation after EBI treatment should be considered when producing oat and barley foods. Overall, this study shows the high potential of EBI for use as a non-thermal technique in stabilising the storage quality of oat and barley.

Genome-wide expansion and reorganization during grass evolution: from 30 Mb chromosomes in rice and Brachypodium to 550 Mb in Avena

BACKGROUND

The BOP (Bambusoideae, Oryzoideae, and Pooideae) clade of the Poaceae has a common ancestor, with similarities to the genomes of rice, Oryza sativa (2n = 24; genome size 389 Mb) and Brachypodium, Brachypodium distachyon (2n = 10; 271 Mb). We exploit chromosome-scale genome assemblies to show the nature of genomic expansion, structural variation, and chromosomal rearrangements from rice and Brachypodium, to diploids in the tribe Aveneae (e.g., Avena longiglumis, 2n = 2x = 14; 3,961 Mb assembled to 3,850 Mb in chromosomes).

RESULTS

Most of the Avena chromosome arms show relatively uniform expansion over the 10-fold to 15-fold genome-size increase. Apart from non-coding sequence diversification and accumulation around the centromeres, blocks of genes are not interspersed with blocks of repeats, even in subterminal regions. As in the tribe Triticeae, blocks of conserved synteny are seen between the analyzed species with chromosome fusion, fission, and nesting (insertion) events showing deep evolutionary conservation of chromosome structure during genomic expansion. Unexpectedly, the terminal gene-rich chromosomal segments (representing about 50 Mb) show translocations between chromosomes during speciation, with homogenization of genome-specific repetitive elements within the tribe Aveneae. Newly-formed intergenomic translocations of similar extent are found in the hexaploid A. sativa.

CONCLUSIONS

The study provides insight into evolutionary mechanisms and speciation in the BOP clade, which is valuable for measurement of biodiversity, development of a clade-wide pangenome, and exploitation of genomic diversity through breeding programs in Poaceae.

Impact of Oat (Avena sativa L.) on Metabolic Syndrome and Potential Physiological Mechanisms of Action: A Current Review

Oat (Avena sativa L.), an annual herbaceous plant belonging to the Gramineae family, is widely grown in various regions including EU, Canada, America, Australia, etc. Due to the nutritional and pharmacological values, oats have been developed into various functional food including fermented beverage, noodle, cookie, etc. Meanwhile, numerous studies have demonstrated that oats may effectively improve metabolic syndrome, such as dyslipidemia, hyperglycemia, atherosclerosis, hypertension, and obesity. However, the systematic pharmacological mechanisms of oats on metabolic syndrome have not been fully revealed. Therefore, in order to fully explore the benefits of oat in food industry and clinic, this review aims to provide up-to-date information on oat and its constituents, focusing on the effects on metabolic syndrome.

Biomass yield, quality, nutrient composition, and feeding value of oat (Avena sativa) silage subjected to different wilting durations and/or inoculant application

In this study, we evaluated the biomass yield, physico-chemical characteristics, nutrient composition, and feeding value of oat (Avena sativa) grown without irrigation ensiled with or without supplemental inoculant following different wilting durations. Oat forage at early dough stage (79 days after sowing) were harvested to assess the biomass yield, nutrient contents, and mineral composition. Oats were ensiled with or without the addition of inoculant and different wilting durations (0, 24, and 48 h) in 3 × 2 factorial arrangement. After the ensiling (120 days), the oat silages were opened, quality was measured in terms of pH, ammonia nitrogen (NH3-N), smell, structure, color, and Flieg point. Nutritional composition and feeding values were analyzed in oat silages. Oat grown without irrigation yielded 32 ton/ha fresh matter. Mean dry matter (DM), organic matter, crude protein (CP), crude fiber, crude ash, ether extract, nitrogen free extract, acid detergent fiber (ADF), neutral detergent fiber, acid detergent lignin, non-structural carbohydrates, hemicellulose, and in vitro dry matter digestibility of oat forage were 32.77%, 90.41%, 11.31%, 28.69%, 9.59%, 3.99%, 46.43%, 36.32%, 63.98%, 7.22%, 11.14%, 27.67%, and 74.81%, respectively. Addition of inoculant had no effect on the quality, nutritional composition, and feeding values of oat silages. Increasing wilting durations linearly increased the pH (P = 0.005) and decreased the smell score (P = 0.028) of ensiled oat. A linear increase was seen in the DM content of ensiled oat after increasing wilting durations (P = 0.001). Oat ensiled without wilting had greater CP content (P = 0.010 and linear P = 0.011) and lower ADF content than those ensiled after 24 or 48 h of wilting (P = 0.013 and linear P = 0.007). Silages subjected to 24 or 48 h of wilting had lower hemicellulose content (P = 0.019 and linear P = 0.012) and digestible DM (P = 0.013 and linear P = 0.007) than those without wilting. In conclusion, inoculant may not affect the quality, composition and feeding values of ensiled oat grown without irrigation whereas, wilting at different durations may negatively affect the pH, smell, CP, ADF, and feeding values of ensiled oats.

Blended extract of oat, sorghum, adzuki bean, finger millet, and proso millet improved hyperglycemia and insulin resistance in the streptozotocin-nicotinamide-induced diabetic rats

Grains contain bioactive components that potentially have protective effects on chronic diseases such as diabetes. The anti-diabetic effects of blended grain ethanol extract (BGE) were evaluated in streptozotocin-nicotinamide (STZ-NA)-induced diabetic rats. BGE was prepared by mixing oat, sorghum, adzuki bean, finger millet, and proso millet (30:30:15:15:10). The rats were assigned into four groups, normal control, diabetic model control (DM), STZ-NA rats administered 200 mg/kg body weight (bw) of metformin, and STZ-NA rats administered 500 mg/kg bw of BGE (BGE). After 6 weeks of administration, the homeostatic model assessment of insulin resistance (12%) in BGE decreased compared to DM. Strikingly, the fasting blood glucose (23%) and oral glucose tolerance test (15%) were improved in BGE compared to DM. BGE also increased insulin immunoreactivities in pancreatic β-cells. In sum, BGE exhibits anti-hyperglycemic effects by improving fasting glucose levels and insulin secretion from pancreatic β-cells in the STZ-NA-induced diabetic rats.

'Single-Seed-SpeedBulks:' a protocol that combines 'speed breeding' with a cost-efficient modified single-seed descent method for rapid-generation-advancement in oat (Avena sativa L.)

BACKGROUND

In plant breeding, one of the most cost-effective and efficient ways to increase genetic gain is to reduce the breeding cycle time. In general, modern breeding methods for self-pollinated crops should strive to develop fixed lines at the lowest possible cost and in the minimum possible amount of time. Previous studies on spring oat (Avena sativa L.) showed that combining high plant density with limited soil fertility and moisture levels in a growth media like sand effectively decreases the time and cost of generating fixed single-seed descent lines. More recently, 'speed breeding,' or the exposure to prolonged photoperiod regimes of 22 h, has been shown to decrease flowering time in oat significantly. The goal of this study was to combine 'speed breeding' with high-density planting in a limited soil fertility media to reduce further the costs and time required to develop oat single-seed-descent lines.

RESULTS

We grew oat plants at low density in potting-mix (control), high density in potting-mix (HD-soil), and high density in sand (HD-sand) under 16 and 22 h of day length. We observed that oat plants grown in HD-sand and exposed to 22 h day length reduced their flowering time by around 20 and 5 days on average compared to those grown in control conditions at 16 and 22 h, respectively. We also observed that 85% of plants grown at high density in sand produced a single seed when grown in bulk conditions. In contrast, only 40% of plants grown at high density in potting-mix produced a single seed.

CONCLUSIONS

Our novel protocol showed that oat plants grown in high-density bulks, using sand media and 22-hour day length, reduced their flowering time by 20 days compared to control conditions and produced plants with single seeds, following closely single-seed descent assumptions while significantly reducing labor costs and greenhouse space. This methodology can be deployed in oat breeding programs to help them accelerate their rate of genetic grain for multiple traits.

Oat AsDA1-2D enhances heat stress tolerance and negatively regulates seed-storage globulin

The importance of oats has increased because of their high nutritional value and health benefits in the human diet. High-temperature stress during the reproductive growth period has a detrimental effect on grain morphology by changing the structure and concentration of several seed-storage proteins. DA1, a conserved ubiquitin-proteasome pathway component, plays an important role in regulating grain size by controlling cell proliferation in maternal integuments during the grain-filling stage. However, there have been no reports or studies on oat DA1 genes. In this study, we identified three DA1-like genes (AsDA1-2D, AsDA1-5A, and AsDA1-1D) using genome-wide analysis. Among these, AsDA1-2D was found to be responsible for high-temperature stress tolerance via a yeast thermotolerance assay. The physical interaction of AsDA1-2D with oat-storage-globulin (AsGL-4D) and a protease inhibitor (AsPI-4D) was observed using yeast two-hybrid screening. A subcellular localization assay revealed that AsDA1-2D and its interacting proteins are localized in the cytosol and plasma membrane. An in vitro pull-down assay showed that AsDA1-2D forms a complex with both AsPI-4D and AsGL-4D. An in vitro cell-free degradation assay showed that AsGL-4D was degraded by AsDA1-2D under high-temperature conditions and that AsPI-4D inhibited the function of AsDA1-2D. These results suggest that AsDA1-2D acts as a cysteine protease and negatively regulates oat-grain-storage-globulin under heat stress.

First report in South Korea of a bacterial leaf blight of oats caused by Pseudomonas salomonii

In March 2020, approximately 20% of leaves in a commercial oat field growing Avena sativa (cv. Samhan) in Jeongeup, Korea (35.3859°, 126.5607°), displayed leaf blight in the seedling stage of development. The lesions observed in 2020 were of a yellow discoloration that spread from the leaf tip downward with minimal brown delineation (Fig. S1A). These symptoms differed from the haloes delineated at the edges by extensive brown necrosis caused by Pseudomonas coronofaciens (Kim 2020a; Fig. S1C). To isolate the causal agent, 3-cm-long pieces of symptomatic leaves from ten different oat plants were disinfected by submersion in 70% ethanol for 5 min followed by immersion in 1% sodium hypochlorite for 5 min and rinsing extensively with sterile distilled water. The air-dried segments were transferred intact to nutrient agar, and only one colony type (yellow-colored, wet, with a shiny convex surface) was observed. After single colony isolation, three isolates from different 2020 field-grown diseased leaves, termed 2007, 2009, and 2011, were selected at random. The isolates produced fluorescent siderophores on King's medium B and triggered a hypersensitive response (HR) when infiltrated into tobacco (cv. Xanthi) leaves (Fig. S1D). Multilocus sequence typing analysis with four housekeeping genes was used for taxonomic identification of these isolates (Maiden et al. 1998). The 16S rRNA sequences were amplified with the 27F/1492R universal primers (Weisburg et al. 1991). The primers for three housekeeping genes were designed using genome sequence of P. coronaficiens X-1 causing halo blight disease in Korea (NZ_CP050260.1, Kim, 2020b). The products obtained had sizes of 640 bp for gltA (using primers F: 5'-CCT GGT AGC CAA GAT GCC GAC-3'; R: 5'-CAA AGA TCA CGG TGA ACA TGC TGG-3'), 710 bp for gyrB (with primers F: 5'-TCG GCA GCC GAG GTC ATC ATG AC-3'; R: 5'-TTG TCT TTG GTC TGC GAG CTG AA-3'), and 870 bp for rpoD ( with primers F: 5'-GTG AAG GCG AAA TCG AAA TCG-3'; R: 5'-CCG ATG TTG CCT TCC TGG ATC AG-3'). The concatenated sequences (2,353 bp/2,376 bp) had 99% identity with the gene sequences from P. salomonii type strain (AY091528.1, NZ_FNOX01000003, LC486864.1, LC486849.1), but lesser identity (90%) with P. coronafaciens (Fig. S2). Pathogenicity of the Korean isolates was confirmed by fulfilling Koch's postulates using leaves of 2 week-old greenhouse-grown 'Samhan' seedlings. Plants (n=50) were sprayed with 108 cfu/ml bacterial suspensions in water or with sterile water as controls. The plants were incubated for a week at 23 °C in 100% relative humidity under a 10 h light/14 h dark photoperiod. Five days after bacterial inoculation, yellow discoloration appeared at the leaf tips which progressed downward with time (Fig. S1B). Three bacterial isolates extracted from yellowed, inoculated leaves had 16S rRNA gene sequences identical to that of P. salomonii Korean isolates, 2007, 2009 and 2011, and they caused the anticipated symptoms when inoculated into oat leaves. These findings indicate that P. salomonii should be added to the potential pathogens of oats grown in Korea. Understanding whether spring weather conditions (warmth and humidity) boost this oat disease will help devise disease alert systems for farmers (Anderson 2004; Chakraborty 2005).

Quantification and classification of deoxynivalenol-contaminated oat samples by near-infrared hyperspectral imaging

Deoxynivalenol (DON) is the most occurring mycotoxin in oat and oat-based products. Near-infrared hyperspectral imaging (NIR-HSI) has been proposed as a promising methodology for analysing DON contamination in the food industry. The present study aims to apply NIR-HSI for DON detection in oat kernels and to quantify and classify naturally DON-contaminated oat samples. Unground and ground oat samples were scanned by NIR-HSI before their DON content was determined by HPLC. The data were pre-treated and analysed by PLS regression and four classification methods. The most efficient DON prediction model was for unground samples (R² = 0.75 and RMSEP = 403.18 μg/kg), using twelve characteristic wavelengths with a special interest in 1203 and 1388 nm. The random forest algorithm of unground samples according to the EU maximum limit for unprocessed oats (1750 μg/kg) achieved a classification accuracy of 77.8 %. These findings indicate that NIR-HSI is a promising tool for detecting DON in oats.

Effect of food matrix and fermentation on angiotensin-converting enzyme inhibitory activity and β-glucan release after in vitro digestion in oat-based products

The aim of this study was to determine the effects of fermentation and food matrix on the ACE inhibitory activities of the peptides obtained after in vitro gastrointestinal digestion, protein profiles (SDS-PAGE) and β-glucan amounts of oat products. Furthermore, the physicochemical and microbiological properties of fermented oat drinks and oat yogurt-like product obtained from oat fermentation were evaluated. Oat grains were mixed with a certain ratio of water 1:3 w/v (oat:water, yogurt consistency) and 1:5 w/v (oat:water, drink consistency), and this mixture was fermented with yogurt culture and probiotic Lactobacillus plantarum and fermented drinks and yogurt were produced. The results indicated that the fermented oat drink and the oat yogurt-like product had L. plantarum viability over 10⁷ cfu/g. After the in vitro gastrointestinal digestion of the samples, the hydrolysis levels ranged from 57.70 % to 82.06 %.The hydrolysis level of the samples with fermented-drink consistency was significantly higher than the samples with yogurt consistency (p < 0.05).The SDS-PAGE profiles of the non-digested samples showed that the bands had molecular weights of 12-15 kDa and around 35 kDa. Bands whose molecular weights were around 35 kDA disappeared after gastric digestion. ACE inhibitory activities of the fractions composed of molecular weights of 2 kDa and 2-5 kDa obtained after in vitro gastrointestinal digestion of the oat samples were in the range of 46.93-65.91 %. The effect of fermentation on the ACE inhibitory activities of the peptide mixture with molecular weights between 2 and 5 kDa was not statistically significant, however, fermentation caused an increase in the ACE inhibitory activities of the peptide mixture with a molecular weight<2 kDa (p < 0.05). The β-glucan amounts of fermented and non-fermented oat products were in the range of 0.57-1.28 %. The β-glucan amounts detected after gastric digestion decreased considerably and β-glucan could not be detected in the supernatant after gastrointestinal digestion. This indicated that β-glucan did not solubilize in the supernatant (bioaccessible) and remained in the pellet. In conclusion, fermentation is a valuable process for releasing peptides with moderately high ACE inhibitory effects from the parent oat proteins.

Biochar improves the performance of Avena sativa L. grown in gasoline-polluted soils

This study investigated the effect of soil contamination by different concentrations of gasoline on oat (Avena sativa L.) and tested the effect of biochar supply to the polluted soils on the performance of oat plants. Oat seeds were sowed in contaminated soils with different concentrations of gasoline: 0% (control), 1%, 2%, 6%, and 10% (v/w), and grown for 2 weeks. Germination, fresh weight, root and stem length, photosynthetic parameters (i.e., chlorophyll content, PI_ABS, F_V/F_M, and NDVI), and total antioxidant power were analyzed. The results showed a remarkable negative effect on almost all the investigated parameters starting from the gasoline concentration of 6%. Based on these results, a new experiment was run by adding 5% (w/w) biochar (a carbon-rich byproduct of wood biomass pyrolysis) to the 6% and 10% polluted soils to test whether adding biochar had a beneficial effect on oat performance. The results showed that biochar supply greatly reduced the negative effects caused by gasoline on all the investigated parameters.

Impact of Oats on Appetite Hormones and Body Weight Management: A Review

PURPOSE OF REVIEW

This study aims to review the hunger hormones in obesity management and the impact of oats in regulating these hormones for hunger suppression and body weight management. In this review, the impact of various edible forms of oats like whole, naked, sprouted, or supplemented has been investigated for their appetite hormones regulation and weight management.

RECENT FINDINGS

The onset of obesity has been greatly associated with the appetite-regulating hormones that control, regulate, and suppress hunger, satiety, or energy expenditure. Many observational and clinical studies prove that oats have a positive effect on anthropometric measures like BMI, waist circumference, waist-to-hip ratio, lipid profile, total cholesterol, weight, appetite, and blood pressure. Many studies support the concept that oats are rich in protein, fiber, healthy fats, Fe, Zn, Mg, Mn, free phenolics, ß-glucan, ferulic acid, avenanthramides, and many more. Beta-glucan is the most important bioactive component that lowers cholesterol levels and supports the defense system of the body to prevent infections. Hence, several clinical studies supported oats utilization against obesity, appetite hormones, and energy regulation but still, some studies have shown no or little significance on appetite. Results of various studies revealed the therapeutic potentials of oats for body weight management, appetite control, strengthening the immune system, lowering serum cholesterol, and gut microbiota promotion by increased production of short-chain fatty acids.

Comparison of physicochemical properties and volatile flavor compounds of plant-based yoghurt and dairy yoghurt

The aim of this study was to investigate and compare the physicochemical characteristics and volatile flavor compounds of three kinds of yoghurt made from reconstituted milk, soy drink and oat drink. The results showed that with the same fermentation ending pH of 4.5, reconstituted yoghurt had the highest titratable acidity mainly due to the highest buffering capacity and microbial counts (LAB). The textural and water holding capacity (WHC) parameters revealed that soy-based yoghurt had the highest firmness, consistency and WHC, indicating more rigid gel was formed. Meanwhile, rheological analysis showed soy-based yoghurt owned higher G' and G'' values and higher stability against external stress, demonstrating that more and stronger interactions between soy proteins were built during fermentation. The confocal laser scanning microscopy (CLSM) image witnessed that soy-based yoghurt had the densest and finest network, while oat-based yoghurt had much coarser and looser structure, which was consistent with the lowest firmness and G' value for oat-based yoghurt. In terms of color, reconstituted yoghurt was the lightest and oat-based yoghurt showed more reddish and yellowish. The main volatile flavor compounds in all yoghurts were ketones, while aldehydes contributed more in soy and oat yoghurt. PCA plot showed that volatile flavor compounds of reconstituted yoghurt and oat-based yoghurt were relatively similar, while soy-based yoghurt was much more different with high OAVs of hexanal, 1-octen-3-one, 1-octen-3-ol and 2-octenal. This study supplied a theoretical basis and an improvement direction for the better development of healthier plant-based yoghurt similar to dairy yoghurt.

Genome-wide identification and characterization of abiotic stress responsive GRAS family genes in oat (Avena sativa)

Background

GRAS transcription factors play a variety of functions in plant growth and development and are named after the first three transcription factors GAI (GIBBERRELLICACIDINSENSITIVE), RGA (REPRESSOROFGAI), and SCR (SCARECROW) found in this family. Oat (Avena sativa) is one of the most important forage grasses in the world. However, there are few reports on the GRAS gene family in oat.

Methods

In order to understand the information and expression pattern of oat GRAS family members, we identified the GRAS members and analyzed their phylogenetic relationship, gene structure, and expression pattern in oat by bioinformatics technology.

Results

The results showed that the oat GRAS family consists of 30 members, and most of the AsGRAS proteins were neutral or acidic proteins. The phylogenetic tree divided the oat GRAS members into four subfamilies, and each subfamily has different conservative domains and functions. Chromosome location analysis suggested that 30 GRAS genes were unevenly distributed on five chromosomes of oat. The results of real-time quantitative reverse transcription-PCR (qRT-PCR) showed that some AsGRAS genes (AsGRAS12, AsGRAS14, AsGRAS21, and AsGRAS24) were all up-regulated with increasing stress treatment time.The results of this study provide a theoretical basis for further research into the corresponding stress of oat. Therefore, further studies concentrating on these AsGRAS genes might reveal the many roles played by GRAS genes in oat.

avenae)

We mapped three adult plant resistance (APR) loci on oat chromosomes 4D and 6C and developed flanking KASP/PACE markers for marker-assisted selection and gene pyramiding. Using sequence orthology search and the available oat genomic and transcriptomic data, we surveyed these genomic regions for genes that may control disease resistance. Sources of durable disease resistance are needed to minimize yield losses in cultivated oat caused by crown rust (Puccinia coronata f. sp. avenae). In this study, we developed five oat recombinant inbred line mapping populations to identify sources of adult plant resistance from crosses between five APR donors and Otana, a susceptible variety. The preliminary bulk segregant mapping based on allele frequencies showed two regions in linkage group Mrg21 (Chr4D) that are associated with the APR phenotype in all five populations. Six markers from these regions in Chr4D were converted to high-throughput allele specific PCR assays and were used to genotype all individuals in each population. Simple interval mapping showed two peaks in Chr4D, named QPc.APR-4D.1 and QPc.APR-4D.2, which were detected in the OtanaA/CI4706-2 and OtanaA/CI9416-2 and in the Otana/PI189733, OtanaD/PI260616, and OtanaA/CI8000-4 populations, respectively. These results were validated by mapping two entire populations, Otana/PI189733 and OtanaA/CI9416, genotyped using Illumina HiSeq, in which polymorphisms were called against the OT3098 oat reference genome. Composite interval mapping results confirmed the presence of the two quantitative trait loci (QTL) located on oat chromosome 4D and an additional QTL with a smaller effect located on chromosome 6C. This mapping approach also narrowed down the physical intervals to between 5 and 19 Mb, and indicated that QPc.APR-4D.1, QPc.APR-4D.2, and QPc.APR-6C explained 43.4%, 38.5%, and 21.5% of the phenotypic variation, respectively. In a survey of the gene content of each QTL, several clusters of disease resistance genes that may contribute to APR were found. The allele specific PCR markers developed for these QTL regions would be beneficial for marker-assisted breeding, gene pyramiding, and future cloning of resistance genes from oat.

Evaluation of salt tolerance of oat cultivars and the mechanism of adaptation to salinity

Soil salinity is a threat to agricultural production worldwide. Oat (Avena sativa L.) is an irreplaceable crop in areas with fragile ecological conditions. However, there is a lack of research on salt tolerance evaluation of oat germplasm resources. Therefore, the purpose of this work was to evaluate the salt tolerance of oat cultivars and investigate the mechanism of salt-tolerant oat cultivars' adaptation to salinity. Salt tolerance of 100 oat cultivars was evaluated, and then two salt-tolerant cultivars and two salt-sensitive cultivars were used to compare their physiological responses and expression patterns of Na⁺- and K⁺-transport-related genes under salinity. Principal component analysis and membership function analysis had good predictability for salt tolerance evaluation of oat and other crops. The 100 oat cultivars were clustered into three categories, with three salt tolerance levels. Under saline condition, salt-tolerant cultivars maintained higher growth rate, leaf cell membrane integrity, and osmotic adjustment capability via enhancing the activities of antioxidant enzymes and accumulating more osmotic regulators. Furthermore, salt-tolerant cultivars had stronger capability to restrict root Na ⁺ uptake through reducing AsAKT1 and AsHKT2;1 expression, exclude more Na⁺ from root through increasing AsSOS1 expression, compartmentalize more Na ⁺ into root vacuoles through increasing AsNHX1 and AsVATP-P1 expression, and absorb more K⁺ through increasing AsKUP1 expression, compared with salt-sensitive cultivars. The evaluation procedure developed in this work can be applied for screening cereal crop cultivars with higher salt tolerance, and the elucidated mechanism of oat adaptation to salinity lays a foundation for identifying more functional genes related to salt tolerance.

Biochemical assessment of oat genotypes revealed variability in grain quality with nutrition and crop improvement implications

Oat is a potent source of nutrients and bioactive compounds offering potential health benefits and role in combating micronutrient malnutrition problems. To exploit nutritional and quality traits of oats, a biochemical assessment of 112 oat genotypes was conducted. The high range of variability for total phenol (1.7-31.3 mg/g), β-glucan (1.0-8.0 mg/g), calcium (1.91-4.34 mg/g), zinc (3.80-6.50 mg/100 g), iron (0.66-4.89 mg/100 g) and manganese (2.88-8.0 mg/100 g) was revealed among genotypes. A higher amount of iron and zinc was found in genotypes OS-6, HFO-638, HFO-915 & HFO-918, whereas, elevated levels of manganese and zinc were recorded in genotypes OS-403 & OL-1804. The results revealed groups of low phytic acid oat genotypes containing high crude protein (HFO-52, HFO-270, HFO-330), β-glucan (HFO-62, HFO-588, HFO-926). A significant positive correlation was obtained between copper with iron, manganese, and calcium content. These findings could be useful for developing value-added oat food products and novel oat varieties.

Toward the development of Ac/Ds transposon-mediated gene tagging system for functional genomics in oat (Avena sativa L.)

Cultivated oat (Avena sativa L.) is an important cereal grown worldwide due to its multifunctional uses for animal feed and human food. Oat has lagged behind other cereals in the genetic and genomic studies attributed to its large and complex genomes. Transposon-based genome characterization has been utilized successfully for identifying and determining gene function in large genome cereals. To develop gene tagging and gene-editing resources for oat, maize Activator (Ac) and Dissociation (Ds) transposons were introduced into the oat genome using the biolistic delivery system. A total of 2035 oat calli were bombarded and twenty-four independent, stable transgenic events were obtained. Transformation frequencies were up to 19.0%, and 1.9% for bialaphos and hygromycin selection, respectively. Re-mobilization of the non-autonomous Ds element, by introducing Ac transposase source, led to a transposition frequency up to 16.8%. The properties of ten unique flanking sequences have been characterized to reveal the Ds-tagged sites in the oat genome. Genes at Ds insertion sites showed homology to gibberellin 20-oxidase 3, (1,3;1,4)-beta-D-glucan synthase, and aspartate kinase. This Ac/Ds transposon-based gene tagging system could facilitate and expedite functional genomic studies in oat.

Genotypic and environmental variations in phenolic acid and avenanthramide content of Canadian oat (Avena sativa)

Phenolic compounds (PC) in oat may possess health promoting properties. This study evaluated the effect of genotype, environment, and their interaction on the phenolic acid and avenanthramide (AVN) concentration in Canadian oat. Six cultivars were grown at eight locations across Canada in a randomised complete block design with three field replicates. Free PCs were extracted from oat groat flour and analysed using a UPLC-PDA system. The cumulative concentration of free PCs and AVN ranged from 58 to 350 and 9 to 244 µg/g, respectively. The effect of environment was significant (p < 0.0001) for the concentration of all PCs. Cultivar differences significantly influenced the concentration of all PCs but AVNs A and B. The growing location explained > 68% of the variation in the concentration of AVN. Thus understanding the genotypic and environmental triggers of individual PCs may help agronomists and breeders strategize in selecting and growing oat cultivars of interest.

Separating the chemical and microbial factors of oat harvested at two growth stages to determine the main factor on silage fermentation

AIMS

This work evaluated the effects of epiphytic microbiota and chemical components on fermentation quality and microbial community of ensiled oat.

METHOD AND RESULTS

Oat harvested at the heading stage (HS) and the milk stage (MS) was sterilized by gamma-ray irradiation and inoculated as the following: (1) HS epiphytic microbiota + sterilized HS (H-H); (2) HS epiphytic microbiota + sterilized MS (H-M); (3) MS epiphytic microbiota + sterilized MS (M-M); (4) MS epiphytic microbiota + sterilized HS (M-H). After 60-d fermentation, silages inoculated with the epiphytic microbiota of HS had higher acetic acid content than those inoculated with MS. While, silage made from sterilized MS had lower pH, ammonia nitrogen and butyric acid contents and higher dry matter, water soluble-carbohydrates and lactic acid contents than that made from sterilized HS. The microbial communities of oat silages were similar, and they were mainly lactobacillus.

CONCLUSIONS

The chemical component rather than the epiphytic microbiota at harvest exerted more effects on oat silages.

SIGNIFICANCE AND IMPACT OF THE STUDY

This work reveals the different effects of chemical and microbial factors on the fermentation of silage, which is instructive for us to produce quality silage.

Genetic diversity in nutritional composition of oat (Avena sativa L.) germplasm reported from Pakistan

In the present study, 30 potential germplasm of oat (Avena sativa L.) were subjected to proximate, elemental, and HPLC analysis to provide a scientific basis to genetic diversity present among them. The extracts of the selected germplasms were also evaluated for their antioxidant potentials through DPPH and ABTS assays. Proximate analysis showed protein contents to be in the range 8.35–17.72% with the highest protein contents in the accession line 22,365 (17.72 ± 0.38%). The genotype-725 showed the highest carbohydrate, and dry matter (53.35 ± 0.01 and 93.50 ± 0.07% respectively) contents whereas, the germplasm-830 contained the highest fat (7.88 ± 0.12%) contents while the highest moisture contents were there in germplasm-22348 (11.95 ± 0.06%). The crude fiber contents (19.67 ± 0.19%) were found high in germplasm-832. The mentioned contents were also correlated to each other where a negative (−0.431*) correlation was noted for crude protein and carbohydrate while ash content to crude protein has a positive (0.38*) correlation. A positive and a negative correlation were there in Crude fats/crude protein (0.30*) and crude fats/moisture contents (−0.39*) respectively. Principal component analysis showed an Eigenvalue of 0.76 with a total variation of 85.01% when applied to proximate components. Based on cluster analysis to proximate composition all the oat germplasms were divided into 5 sub-clusters, where accession numbers 769 and 817 were found to be the most diverse genotypes. The elemental analysis confirmed the presence of magnesium (2.89–7.62 mg/L), sodium (3.71–8.03 mg/L), manganese (0.93–3.71 mg/L), copper (0.35–3.36 mg/L), iron (2.15–6.82 mg/L), zinc (1.30–3.37 mg/L), chromium (0.37–3.34 mg/L), and potassium (50.70–59.60 mg/L) in the selected germplasms. Principal component analysis for elemental composition showed the total variation of 73.75% with the Eigenvalue of 0.97. Cluster analysis on an elemental basis divided all the oat germplasms into 7 sub-clusters where accession numbers 769 and 22,350 were found to be the most diverse germplasm. Phytochemical analysis performed through HPLC resulted in the identification of nine possible compounds (malic acid, epigallocatechin gallate, quercetin, morin, ellagic acid, catechin hydrate, rutin, pyrogallol, and mandelic acid) in various germplasm of oat. A concentration-dependent antioxidant response was recorded when extracts were tested as an inhibitor of DPPH and ABTS free radicals. The results revealed that oat grains are a good source of nutrients, minerals, and phytochemicals that can be used as nutraceuticals and as food. The genetic differences revealed that this plant can be grown under varied environmental conditions.

High-intensity ultrasound as pre-treatment in the development of fermented whey and oat beverages: effect on the fermentation, antioxidant activity and consumer acceptance

This study aimed to evaluate the effect of high-intensity ultrasound as pre-treatment in the development of fermented whey and oat beverages. Oat malt was produced, incorporated into a whey formulation (35, 50 and 65% v/v of whey) and ultrasonicated (at 40 kHz and 11 W/cm²) for 0, 3 or 10 min, prior to fermentation with L. casei 431. The treatments were identified as 35/65/0, 50/50/0, 65/35/0, 35/65/3, 50/50/3, 65/35/3, 35/65/10, 50/50/10 and 65/35/10, referring to the whey percentage, oat percentage, and the ultrasound time (min), respectively. The beverages 50/50/0 and 50/50/3 registered the highest (P < 0.05) growth with 1.96 and 2.00 log CFU ml, respectively. In general, the final average population of L. casei 431 was 7 to 8.86 log CFU/ml, being this adequate for a probiotic beverage. The highest antioxidant activity was found in the 35/65/3, 35/65/10, 50/50/3 and 50/50/10 beverages without difference (P < 0.05) among them. There was no effect of gender on the acceptance of the probiotic beverages. The best accepted beverage by women was 50/50/3 and both genders disliked the beverage 35/65/10. There was no relationship between the acceptance of the beverages and the consumers' habit by fermented milk beverages. No difference in the preference between the 50/50/0 and the 50/50/3 beverage was found. It is concluded that the probiotic beverage containing 50% whey and 50% oat and ultrasonicated for 3 min generated the highest levels of L. casei 431 growth, high antioxidant activity and good consumer acceptance and preference.

Mushroom and cereal β-D-glucan solid state NMR and FTIR datasets

In the associated published article Kremmyda et al. (2021), the C1 region of the NMR spectra were examined in detail, as the C1 carbon was common to the crucial linkages in the glucan, and the most clearly separated region in the spectra. We provide the original measurement data here in topspin format, in order that different authors can examine the regions corresponding to the other carbons and in addition repeat our processing of the FID's using different parameters.

Mushroom, Cereal, Reference and other samples, such as salts and salt hydrates have been measured. A series of different experiments on individual samples is also given. All of the samples and experiments available in the database are summarised in the Table below.

We also provide an FTIR database in the form of an excel workbook with spectra in frequency/absorbence pairs.

Combined foliar and soil selenium fertilizer improves selenium transport and the diversity of rhizosphere bacterial community in oats

Agronomic selenium (Se) biofortification of grain crops is considered the best method for increasing human Se intake, which may help people alleviate Se-deficiency. To investigate the efficiency of agronomic Se biofortification of oat, four Se fertilizer application treatments were tested: topsoil (T), foliar (S), the combination of T and S (TS), and control without Se application (CK). Compared with CK, TS significantly increased the 1000-grain weight, grain yield, Se contents in all parts of oats, contents of soil available N, K, and organic matter by 18%, 8.70%, 19.7-60.2%, 6.00%, 8.02%, and 17.95%, respectively. Leaves, roots, and ears had the highest conversion rate of exogenous Se in S (644.63%), T (416.00%), and TS (273.20%), respectively. TS also increased the activities of soil urease, alkaline phosphatase, and sucrose and the diversity of soil bacterial communities. TS and T increased the relative abundance of bacteria involved in the decomposition of organic matter, such as Actinobacteria, Gemmatimonadetes, Chloroflexi, and Bacteroidetes positively correlated with soil nutrients and enzyme activities, and reduced Proteobacteria and Firmicutes negatively correlated with them, Granulicella, Bacillus, Raoultella, Lactococcus, Klebsiella, and Pseudomonas. Furthermore, TS significantly increased the relative abundance of Planctomycetes, Chlorobi, Nitrospinae, Nitrospirae, Aciditeromonas, Gemmatimonas, Geobacter, and Thiobacter. T significantly increased the abundance of Lysobacter, Holophaga, Candidatus-Koribacter, Povalibacter, and Pyrinomonas. S did not significantly change the bacterial communities. Thus, a combined foliar and soil Se fertilizer proved conducive for achieving higher yield, grain Se content, and improving Se transport, the diversity of rhizosphere bacterial community, and bacterial functions in oats.

The effect of cereal Β-glucan on body weight and adiposity: A review of efficacy and mechanism of action

The current review examines the totality of the evidence to determine if there exists a relationship between β-glucan and body weight and adiposity and whether such a relationship is a consistent, causal and plausible one. Observational studies suggest an association between oat (i.e., β-glucan) intake and reduced body weight, waist circumference and adiposity. High and moderate quality randomized controlled trials that were specifically designed to evaluate the efficacy of β-glucan on anthropometric outcomes were given the highest weight. Several of these studies indicated a causal relationship between β-glucan consumption and reduction in body weight, BMI, and at least one measure of body fat within diets that were not calorie-restricted. A review of additional animal and human evidence suggests multiple plausible mechanisms by which β-glucan may impact satiety perception, gastric emptying, gut hormones, gut microbiota and short chain fatty acids in the complex interplay of appetite and energy regulation.

Genomic prediction and training set optimization in a structured Mediterranean oat population

The strong genetic structure observed in Mediterranean oats affects the predictive ability of genomic prediction as well as the performance of training set optimization methods. In this study, we investigated the efficiency of genomic prediction and training set optimization in a highly structured population of cultivars and landraces of cultivated oat (Avena sativa) from the Mediterranean basin, including white (subsp. sativa) and red (subsp. byzantina) oats, genotyped using genotype-by-sequencing markers and evaluated for agronomic traits in Southern Spain. For most traits, the predictive abilities were moderate to high with little differences between models, except for biomass for which Bayes-B showed a substantial gain compared to other models. The consistency between the structure of the training population and the population to be predicted was key to the predictive ability of genomic predictions. The predictive ability of inter-subspecies predictions was indeed much lower than that of intra-subspecies predictions for all traits. Regarding training set optimization, the linear mixed model optimization criteria (prediction error variance (PEVmean) and coefficient of determination (CDmean)) performed better than the heuristic approach "partitioning around medoids," even under high population structure. The superiority of CDmean and PEVmean could be explained by their ability to adapt the representation of each genetic group according to those represented in the population to be predicted. These results represent an important step towards the implementation of genomic prediction in oat breeding programs and address important issues faced by the genomic prediction community regarding population structure and training set optimization.

Silage fermentation characteristics and microbial diversity of alfalfa (Medicago sativa L.) in response to exogenous microbiota from temperate grasses

The objective of this study was to explore the microbiological factors that cause the difference in silage fermentation characteristics between grass and legume. Specifically, the effects of epiphytic microbiota from alfalfa, oat and Italian ryegrass on ensiling characteristics and microbial community of alfalfa were assessed. By γ-ray irradiation sterilization and microbiota transplantation technology, the sterile alfalfa was inoculated as follows: (i) aseptic water (STAL); (ii) epiphytic bacteria from alfalfa (ALAL); (iii) epiphytic bacteria from oat (ALOT); (iv) epiphytic bacteria from Italian ryegrass (ALIR). Alfalfa at the initial flowering stage was ensiled in laboratory-scale silos for 1, 3, 7, 14, 30 and 60 days. Compared with ALAL and ALIR, higher lactic acid contents and ratio of lactic acid to acetic acid, and lower acetic acid, propionic acid, ethanol and ammonia nitrogen contents were observed in ALOT after 60 days of fermentation. In each treated group, Lactobacillus was the most dominant genus after 60 days of ensiling. Relatively higher abundance of Weissella, Hafnia-Obesumbacterium, Enterobacteriaceae or hetero-fermentative Lactobacillus was found in ALAL and ALIR after 60 days. Co-occurrence network analysis proved Pediococcus and Lactococcus were pivotal in deciding the fermentation pattern of alfalfa silage. According to the 16S rRNA gene-predicted functional profiles, the metabolism of amino acids was inhibited by the epiphytic microbiota from oat. Overall, ALOT showed a homo-fermentative process, whereas ALAL and ALIR exhibited a hetero-fermentative pattern. Furthermore, the exogenous microorganisms inhibiting the metabolism of amino acids can be a good potential source to improve the silage quality of legume forage.

Thermal, pasting and structural studies of oat starch-caseinate interactions

The effects of different concentrations of calcium caseinate (CaCn) on pasting, thermal and structural properties of oat starch were investigated. The effect of CaCn on oat starch was highly dependent on the concentration of CaCn in the mixtures. Characterizations of pasting properties revealed that breakdown, final and setback viscosities increased at high relative contents of CaCn (>50%, w/w), while setback and stability ratio were decreased. Thermal analysis showed an increase in gelatinization temperature and a decrease in enthalpy change. The X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) suggested significant effects of CaCn on oat starch gelatinization. Based on XRD results, a decreasing trend was observed on the relative crystallinity of the starch-protein mixtures containing high levels of CaCn (e.g. 50% and 75% relative CaCn contents). Increases in FT-IR bands at 1024 cm^-1 and 1152 cm^-1 suggested an increase in amorphous structuration of the mentioned starch-protein mixtures.

Evaluation of exotic oat (Avena sativa L.) varieties for forage and grain yield in response to different levels of nitrogen and phosphorous

A field experiment was conducted during the Rabi season 2017–2018 (October–March) at the University of Agriculture, Peshawar research farm to examine the influence of different nitrogen (N) and phosphorus (P) levels on two different oat varieties: Australian and Ukrainian. The treatments included control and three levels of nitrogen and phosphorus at 30, 60, and 90 kg ha⁻¹. The treatments were arranged in randomized complete block design (RCBD) and replicated three times. The findings showed that the oat varieties were significantly different from one another in yield and yield parameters. The Australian variety recorded higher emergence (49 plants m⁻²), days to emergence (15 days), days to flowering (122 days), days to maturity (145 days), plant height (142.7 cm), number of leaves (6.03 leaves plant⁻¹), number of tillers (92.2 tillers m⁻¹), biological yield (8,179.2 kg ha⁻¹), and grain yield (3,725.6 kg ha⁻¹) than the Ukrainian variety. Similarly, different N and P levels, the maximum days to emergence, days to flowering, and days to maturity were recorded in a control plot. The application of 105 kg N + 90 kg P ha⁻¹ was statistically similar to the application of 105 kg N + 60 kg P ha⁻¹. Maximum emergence (60 plants m⁻²), number of leaves (7.0 leaves plant⁻¹), plant height (118.6 cm), number of tillers m⁻¹ (102.6), biological yield (9,687.5 kg ha⁻¹), and grain yield (4,416.7 kg ha⁻¹) were determined in Australian variety. Based on the findings of this study, the Australian variety performed better in terms of yield and yield components and the application of N and P fertilizers at the rate of 105 kg N + 60 kg P ha⁻¹ produced the best results in both oat varieties.

A comparative assessment of the nutritional composition of dairy and plant-based dairy alternatives available for sale in the UK and the implications for consumers' dietary intakes

The popularity of plant-based dairy alternatives (PBDAs) products has grown exponentially in recent years creating a new market of PBDA. The aim of this study was to compare the nutritional content of plant-based alternatives of milk, yogurt and cheese with dairy equivalents and the impact on nutritional intake across the lifespan when they are substituted into UK diets. Nutritional information from cow's milk, yogurt, cheese and PBDAs available on the UK market was collected via manufacturers information. The products were categorised according to primary plant-based ingredient/s and compared with the equivalent dairy product. The National Diet and Nutrition Survey data was used to calculate the intake of milk, yogurt and cheese across all age groups and the energy and nutrient intake was calculated. Plant-based milk, cheese and yogurt alternative categories were then substituted for dairy intakes, and energy and nutrient intakes were calculated and compared to UK Dietary Reference Values. A total of 299 PBDA products were identified consisting of 136 milk alternatives, 55 yogurt alternatives and 109 cheese alternatives. All PBDAs were more expensive than dairy products. Milk contained more energy, saturated fat, carbohydrates, protein, vitamin B₂, vitamin B₁₂ and iodine, and less fibre and free sugars, than plant-based milk alternatives (P < 0.05). There were significant differences between yogurt and cheese and their corresponding PBDAs for energy, fat, saturated fat, carbohydrate, sugars, fibre protein, salt, and calcium (P < 0.05). These differences were reflected in the nutrient intakes of different age groups and the results demonstrated that PBDA may be useful as practical replacements of dairy products but cannot be considered nutritional replacements.

Effects of steam-flaked grains on foals' growth and faecal microbiota

Background

There is little objective information concerning the effect of steam-flaked grains on foal’s growth performance and faecal microbiota. To determine the effects of steam-flaked grains on foal’s growth performance and faecal microbiota, faecal samples were collection from 18 foals which had been fed either corn, oat or barley diets over the 60 days of the experiment. Body weight and conformation measurements were collected. Next-generation sequencing of the V3 + V4 region of the 16 S rRNA gene was used to assess the microbial composition of faeces. Alpha diversity, Venn graph, Relative abundance and beta diversity are presented.

Results

There was a significantly higher larger increase in the body weight of those foals fed barley compared to either corn or oats. There were also significant changes in the Alpha diversity of the gut microbiota. The Shannon and Simpson indices were significantly higher in the barley fed group than those fed corn or oats. The Chao1 index was significantly higher in the oat fed group than the corn or barley fed groups. There were significant changes in the relative abundance of bacteria in the microbiota in terms of phylum, family and genus. The histogram of LDA value distribution showed that the 12 statistically different biomarkers of the bacteria were present. Tax4Fun function annotation clustering heat map showed that functional information was detected from 26 species of bacteria in faecal samples from the foals.

Conclusions

Differences by starch sources were found in overall growth of the foals and in the faecal microbiota if either supplementary corn, oat or barley was fed. Further studies are required to determine the potential impact of the changes in the microbiota on the health and development of foals fed cereal starch of different sources.

A review of treatment modalities in gyrate atrophy of the choroid and retina (GACR)

Gyrate atrophy of the choroid and retina (GACR) is a rare inborn error of amino acid metabolism caused by bi-allelic variations in OAT. GACR is characterised by vision decline in early life eventually leading to complete blindness, and high plasma ornithine levels. There is no curative treatment for GACR, although several therapeutic modalities aim to slow progression of the disease by targeting different steps within the ornithine pathway. No international treatment protocol is available. We systematically collected all international literature on therapeutic interventions in GACR to provide an overview of published treatment effects.

METHODS

Following the PRISMA guidelines, we conducted a systematic review of the English literature until December 22nd 2020. PubMed and Embase databases were searched for studies related to therapeutic interventions in patients with GACR.

RESULTS

A total of 33 studies (n = 107 patients) met the inclusion criteria. Most studies were designed as case reports (n = 27) or case series (n = 4). No randomised controlled trials or large cohort studies were found. Treatments applied were protein-restricted diets, pyridoxine supplementation, creatine or creatine precursor supplementation, l-lysine supplementation, and proline supplementation. Protein-restricted diets lowered ornithine levels ranging from 16.0-91.2%. Pyridoxine responsiveness was reported in 30% of included mutations. Lysine supplementation decreased ornithine levels with 21-34%. Quality assessment showed low to moderate quality of the articles.

CONCLUSIONS

Based primarily on case reports ornithine levels can be reduced by using a protein restricted diet, pyridoxine supplementation (variation-dependent) and/or lysine supplementation. The lack of pre-defined clinical outcome measures and structural follow-up in all included studies impeded conclusions on clinical effectiveness. Future research should be aimed at 1) Unravelling the OAT biochemical pathway to identify other possible pathologic metabolites besides ornithine, 2) Pre-defining GACR specific clinical outcome measures, and 3) Establishing an international historical cohort.

First Report of Gray Leaf Spot Caused by Pyricularia oryzae (synonym: Magnaporthe oryzae) in Oat (Avena sativa) in Georgia, USA

In southeastern U.S., oat (Avena sativa L.) is predominantly grown as a grain or forage crop due to its exceptional palatability (Buntin et al. 2009). In November 2020, leaf spot symptoms were observed in an oat field (cv. Horizon 720) in Screven County, Georgia (GPS: 32°38'57.6"N 81°31'32.178"W). Lesions were oblong, whitish to gray in color, and surrounded by dark brown borders. Symptomatic oat leaves were sampled from the field and cut into 1 cm2 sections that were surface sterilized, plated onto Potato Dextrose Agar (PDA) media and incubated in the dark at 23°C. To obtain pure cultures, fungal hyphal tips were transferred onto fresh PDA plates 3 times. The pathogen was identified as Pyricularia (Magnaporthe) based on typical conidial morphology (Ellis 1971). Conidia were hyaline, pyriform, 2-septate, and displayed a basal hilum. Conidia measured 5.32 to 10.64 μm (average 8.24 μm) wide by 15.96 to 29.26 μm (average 25.40 μm) long. The identification of Pyricularia was further confirmed genetically via PCR amplification followed by sequencing. Genomic DNA was extracted from a 14-day old pure culture using a CTAB method (Doyle and Doyle 1987). The internal transcribed spacer (ITS) region of ribosomal DNA, calmodulin (CaM) gene, and -tubulin (TUB) gene were amplified using ITS5-ITS4 (White et al. 1990), CMD5-CMD6 (Hong et al. 2005), and Bt2a- Bt2b (Glass and Donaldson 1995) primer sets, respectively. Amplicons were Sanger sequenced and blasted against the NCBI database. Results exhibited 100% (ITS), 100% (CaM), and 99.61% (TUB) homology with Pyricularia oryzae Cavara (GenBank accession no. LC554423.1, CP050920.1, and CP050924.1, respectively). The ITS, CaM, and TUB sequences of the isolate were deposited in GenBank as MZ295207, MZ342893, and MZ342894, respectively. In a greenhouse (23°C, 80% RH), Koch's postulates were carried out by using oat seedlings cv. Horizon 270 grown in Kord sheet pots filled with Sun Gro professional growing mix, and a P. oryzae spore suspension containing 104 conidia ml-1. The spore suspension (10 ml) was sprayed with an air sprayer onto 7 pots of oat seedlings at the two-leaf stage. Seven supplementary pots of oat seedlings of the same cultivar were sprayed with sterile water to act as controls. After inoculation, plants were covered with black plastic bags that had been sprayed with sterile water to maintain high humidity and incubated overnight in the greenhouse. The bags were removed the next day, and plants were evaluated for symptoms in the following days. Seven days after inoculation, plants displayed symptoms similar to those found in the original field sample. Control plants showed no symptoms. Pyricularia oryzae was consistently re-isolated from inoculated symptomatic oat tissues. To our knowledge, this is the first report of gray leaf spot caused by P. oryzae on oat in the state of Georgia and in the continental United States. Pyricularia oryzae can infect several graminaceous plants, including agronomically important crops such as rice (Oryza sativa) and wheat (Triticum spp.) (Chung et al. 2020). Phylogenetic analysis on the ITS region using 6 different host lineages was performed and revealed that this oat isolate was most closely related to the Lolium lineage. This outbreak could have economic implications in oat production.

Acrylamide and 5-hydroxymethylfurfural in thermally treated non-wheat flours and respective breads

This is the first report about the influence of dry and wet heat treatment on acrylamide content in flours and, subsequently, in breads. It was shown that during production of some breads acrylamide content decreases. Dry heating of non-wheat flour resulted in acrylamide in flours of sorghum (160 µg/kg); millet (447 µg/kg); barley (516 µg/kg); triticale (868 µg/kg); rye (1833 µg/kg); oat (1951 µg/kg). Hydrothermal heating had a negligible impact on acrylamide formation. In breads made from flour blends consisted of 70% of dry thermally and 30% of hydrothermally treated flours of millet, sorghum, oat, and rye, respectively, acrylamide was detected in the range from 105 to 312 µg/kg. 5-hydroxymethylfurfural probably contributing to acrylamide formation in bread was detected in the range from 2.0 mg/kg to 44.3 mg/kg in dry heated flours; in hydrothermally treated flours was below LOQ (1.7 mg/kg); in breads was between 3.3 and 8.0 mg/kg.

The anti-hypoxic effects of oat (Avena sativa L.) oligopeptides in mice

OBJECTIVE

To explore the anti-hypoxic effects of oat oligopeptides (OOPs) in mice.

METHODS

We randomly divided mice into six groups, including a vehicle control group, a whey protein group (0.50 g/kg), and four OOPs-treated groups (0.25, 0.50, 1.00, and 2.00 g/kg). The test substances were administered by gavage once a day for 30 days. The normobaric hypoxia, sodium nitrite toxicosis, and acute cerebral ischemia survival times were recorded. Also, the MDA content, the lactate levels, the LDH activity, and the mRNA levels of HIF-1α and VEGF in the brains were measured. We performed a whole blood cell analysis using a blood analyzer.

RESULTS

The OOPs significantly extended the survival times of normobaric hypoxia, sodium nitrite toxicosis, and acute cerebral ischemia. Notably, the OOPs enhanced the RBC, Hb, and Hct levels, decreased the malonaldehyde (MDA) and lactate content in the brain, enhanced the brain lactate dehydrogenase (LDH) activity, and increased the hypoxia-inducible factor 1alpha (HIF1α) mRNA and the vascular endothelial growth factor (VEGF) mRNA expression levels.

CONCLUSION

OOPs have anti-hypoxic effects, and the mechanism may involve improving the blood's oxygen carrying capacity and oxygen utilization rate minimizing the lipid peroxidation lesions, increasing the brain's ability to buffer against lactic acidosis in mice, and promoting angiogenesis and regulating the hypoxic response.

Integrative analysis of transcriptome and metabolome reveal mechanism of tolerance to salt stress in oat (Avena sativa L.)

Soil salinity is among the crucial factors that impact on crop productivity, including oat (Avena sativa L.). Herein, we used two distinct oat cultivars with varied salt tolerance levels to unravel adaptive responses to salt stress by metabolomic and transcriptomic characterization. Metabolomic profiling revealed 201 metabolites, including saccharides, amino acids, organic acids, and secondary metabolites. The levels of most saccharides and amino acids were elevated in Baiyan 2 (BY2) as well as in Baiyan 5 (BY5) exposed to salt stress. In the tolerant cultivar BY2 exposed to 150 mM NaCl, concentrations of most of the metabolites increased significantly, with sucrose increased by 38.34-fold, Sophorose increased by 314.15-fold and Isomaltose 2 increased by 25.76-fold. In the sensitive cultivar BY5, the concentrations of most metabolites increased after the plant was exposed to 150 mM NaCl but decreased after the plant was exposed to 300 mM NaCl. Transcriptomic analysis revealed that gene expressions in BY5 were significantly affected under exposure to 300 mM NaCl (34040 genes up-regulated and 14757 genes down-regulated). Assessment of metabolic pathways as well as KEGG enrichment revealed that salt stress interferes with the biosynthesis of two oat cultivars, including capacity expenditure and sugar metabolism. Most of the BY2 genes enhanced energy consumption (for example, glycolysis) and biosynthesis (for instance, starch and sugar metabolism) under salt stress. In contrast, genes in BY5 were found to be down-regulated, leading to the inhibition of energy consumption and biosynthesis, which may also be attributed to salt sensitivity in BY5. In addition, the modified Na⁺/K⁺ transporter genes expression is associated with the predominant ionic responses in BY2, which leads low concentration of Na⁺ and high K⁺ when exposed to high salt situations. These findings suggest that the varied defensive capacities of these two oat cultivars in response to salt stress are due to their variations in energy-expenditure strategy, synthesis of energy substances and ion transport in roots. Our present study offers a crucial reference for oat cultivation under saline soil.

Deciphering the dynamic gene expression patterns of pollen abortion in a male sterile line of Avena sativa through transcriptome analysis at different developmental stages

BACKGROUND

Male sterility (MS) has important applications in hybrid seed production, and the abortion of anthers has been observed in many plant species. While most studies have focused on the genetic factors affecting male sterility, the dynamic gene expression patterns of pollen abortion in male sterile lines have not been fully elucidated. In addition, there is still no hybrid oat that is commercially planted due to the lack of a suitable system of male sterility for hybrid breeding.

RESULTS

In this study, we cultivated a male sterile oat line and a near-isogenic line by crossbreeding to elucidate the expression patterns of genes that may be involved in sterility. The first reported CA male sterile (CAMS) oat line was used for cross-testing and hybridization experiments and was confirmed to exhibit a type of nuclear sterility controlled by recessive genes. Oat stamens of two lines were sampled at four different developmental stages separately. Paired-end RNA sequencing was performed for each sample and generated 252.84 Gb sequences. There were 295,462 unigenes annotated in public databases in all samples, and we compared the histological characteristics and transcriptomes of oat stamens from the two oat lines at different developmental stages. Our results demonstrate that the sterility of the male sterile oat line occurs in the early stage of stamen development and is primarily attributable to abnormal meiosis and the excessive accumulation of superoxide.

CONCLUSIONS

To the best of our knowledge, this study is the first to decipher the dynamic expression profiles of pollen abortion CAMS and CA male fertile (CAMF) oat lines, which may represent a valuable resource for further studies attempting to understand pollen abortion and anther development in oats.

[Lactic starter cultures to improve the oat bioactive compounds]

The objective of this work was to study lactic fermentation as a biostrategy to enhance the antioxidant activity of oats. The adaptability of 31 strains of lactic bacteria (LB) in an oats/water system (OWS/SAA) was evaluated, measuring growth, acidification and fermentation activity (impedimetric method; detection time [DT], maximum rate of conductance change [MRCC/VMCC] and percentage of conductance change [PCC]). Moreover, the content of phenolic compounds (PC) was determined using the Folin-Ciocalteu method (gallic acid equivalents [GAE]), free peptides and amino acids and free radical scavenging activity (DPPH^• and ABTS^•+ methods) of methanolic and aqueous extracts obtained from fermented OWS/SAAs (fOWS/SAAf) were determined. Six strains have shown the best adaptability to SAA, with high values of VMCC (0.34-0.47 μS/min) and PCC (53.6-66.6%), and low values of DT (≤ 3 h). In these f/OWS/SAAf the chemical composition was also modified (PC concentration, peptides and free amino acids) with strain-dependent behavior. The PC content in f/OWS/SAAf using these six strains (29.1-36.9 μg GAE/ml) was higher than the control content in OWS/SAA control (17.1 ± 1.9 μg GAE/ml). An increase (9-25.5%) in antioxidant activity in f/OWS/SAAf methanolic extracts was detected using both methods. Minor modifications were observed in the peptide and free amino acid content of SAA and their antioxidant activity. Our results show LB ability to adapt to oat as fermentation substrate and increase the content of its antioxidant compounds.

Analysis of β-d-glucan biosynthetic genes in oat reveals glucan synthesis regulation by light

BACKGROUND AND AIMS

Oat (Avena sativa) has human health benefits when consumed as a whole-grain food, attributed to the high content of (1,3;1,4)-β-d-glucan (mixed-linkage glucan [MLG]), but little is known about the synthase genes and synthesis mechanism of MLG polysaccharides in this species.

METHODS

The concentration of oat MLGs under different light intensities was measured by a standard enzymatic approach and further verified by immunoelectron microscopy. The effect of light intensity on MLG synthase genes was examined by RT-qPCR and western blot analyses. The pattern of expression directed by the promoter of the oat MLG synthase gene was also investigated by histochemical β-glucuronidase (GUS) analysis.

KEY RESULTS

The oat orthologues of genes implicated in the synthesis of MLG in other cereals, including cellulose synthase-like (Csl) F, H and J gene families, were defined. Transcript profiling of these genes across oat tissues indicated that AsCslF6 transcripts dominated. Under high light intensities, the expression of AsCslF6, a major isoform of the MLG synthase genes, increased to >30 % of the dark growth control. The amount of MLG in oat rose from 0.07 to 1.06 % with increased light intensity. Histochemical tests showed that the AsCslF6 gene promoter preferentially directs GUS expression under high light intensity conditions.

CONCLUSIONS

Oat MLG synthesis is regulated by light. High light intensity upregulates the expression of the MLG synthase AsCslF6 gene, leading to an increase in the amount of MLG in oat leaves.

Water-insoluble dietary fibers from oats enhance gel properties of duck myofibrillar proteins

The effects of different particle sizes (90-µm and 200-µm) and contents (1.5% and 3%) of water-insoluble dietary fibers (IDF) on the gelation properties of duck myofibrillar protein (MP) were explored. The results showed that the addition of IDF improved the gel strength and water holding capacity of MP compared with the control (P < 0.05). IDF reinforced the formation of network structure and the viscoelasticity of gel; 1.5% 200-µm IDF reached the maximum among these treatments. PT₂₁ of the gel with IDF was higher than that of the control (P < 0.05), revealing that the addition of IDF accelerated the transformation of free water into immobilized water within the gel matrix. An ordered flaky gel network with small water holes was responsible for the increase of fractal dimension of the gel with IDF. Water distribution and viscoelasticity are the critical factors that IDF affects the gel properties of duck MP.

The effect of beta-glucan supplementation on glycemic control and variability in adolescents with type 1 diabetes mellitus

AIMS

This study aimed to investigate whether supplemental soluble fiber, oat β-glucan, has any effect on glycemic control and variability of adolescents with type 1 diabetes mellitus.

METHODS

This study was conducted in 30 adolescents with type 1 diabetes mellitus and it consisted of three phases lasting one week. At Phase I, all subjects followed a standard diet program. For Phase II and Phase III, the subjects continued their standard diet program and added natural oat flakes containing 3 g/day and 6 g/day β-glucan, respectively. Glucose levels were monitored by continuous glucose monitoring (CGM). The maximal, minimal, mean and daytime and night blood glucose levels, percentages of glucose values in a target range and below and above a target values were calculated for each of the phases. Premeal, postmeal, peak blood glucose values and peak times of meals were evaluated for each of the phases. Glycemic variability was measured via SD, CV, MAGE, IQR, MODD, LBGI, HBGI, and CONGA parameters.

RESULTS

The maximal, mean and daytime and night blood glucose levels were the lowest at Phase III (p < 0.05). Minimal blood glucose levels were the highest at Phase III (p < 0.05). Phase I, II, and III showed similar durations elapsed for Level 2 and Level 1 hypoglycemia, euglycemia, Level 1 and Level 2 hyperglycemia (p > 0.05). Premeal and postmeal blood glucose levels were lowest at Phase III for breakfast, lunch, and overall (p < 0.05). The lowest peak blood glucose levels were detected at Phase III for breakfast, lunch, dinner and overall (p < 0.05). Phase III also showed delayed peaks for all time-points (p < 0.05 for each) compared to other phases. Phase III had significantly lower levels of SD, CV, LBGI, and CONGA levels than those in either Phase I or Phase II (p < 0.05 for each).

CONCLUSION

6 g/day oat β-glucan have favorable outcomes in glycemic control and variability in adolescents with type 1 diabetes mellitus.

First Report of Leaf Spots on Oat Caused by Alternaria alternata in South Korea

Oat, a gluten-free source of vitamins, minerals, fiber, and antioxidants required for human health (Rasane et al., 2015), is increasingly being cultivated in South Korea (Ju et al. 2011). In May 2020, ~30 % Avena sativa (cv. Samhan) leaves of a commercial oat field in Jeongeup, Korea (35.3859°N, 126.5607°E), displayed a leaf spot disease at the tillering growth stage. Small, brown spots appeared initially on the lower leaves, but progressed to dark-brown oval or irregular, necrotic spots with a light-yellowish border. To isolate the pathogen, tissue excised from growing edges of about 50 lesions was surface sterilized (immersion in 70 % ethanol then 1 % sodium hypochlorite), rinsed and transferred to potato dextrose agar. Five isolates were purified using the single-spore culture method on water agar plates (Choi et al. 1999). Conidia from the PDA cultures (n = 50) were elongated, ellipsoidal, and obclavate, with one to five septa (primarily transverse), 18 to 35 μm × 7 to 12 μm. The morphological characteristics of the fungus from each culture were consistent with those observed for Alternaria alternata (Chen et al. 2020; Simmons 2007). To confirm the identity of the fungal pathogen, the internal transcribed spacer (ITS) region was amplified with universal primers ITS1/ITS4 and sequenced (White et al. 1990). BLAST analysis of the resulting nucleotide sequence of one representative isolate, Oaa-2 (GenBank MT786424), showed 100 % identity with A. alternata-type strains, such as CBS916.96. Further, nine nuclear protein-coding genes from the Oaa-2 isolate were amplified using previously described primers (Lawrence et al. 2013; Wouderengerg et al. 2015). These sequences were deposited under the following GenBank accession numbers: MT795660 (rpb2), MT795656 (His), MT795657 (CML), MT795658 (ACT), MT787343 (CHSD), MT795655 (GAPDH), MT795661 (endoPG), and MT795662 (TEF1). The nine sequences of the Oaa-2 isolate showed 99%-100 % identity to those of A. alternata-type strain CBS916.96 in NCBI. Fig. S2 shows the phylogenetic trees for the ITS and GAPDH sequences indicating high homology. Pathogenicity of this isolate was confirmed by spraying leaves of surface-sterilized, glasshouse-grown, "Samhan" oats with suspensions (5 × 106 spores/ml) of Oaa-2 conidia. Experimental seedlings were grown for 2 weeks in a chamber at 20 ± 3 °C in 60 % relative humidity with a 10-h light/14-h dark cycle (200 µmol/m2/s). Conidial suspensions were prepared for inoculation by flooding with sterile water, followed by filtering the suspension through three layers of sterile cheesecloth to remove debris. Three pots each containing twenty oat seedlings were sprayed with the Oaa-2 isolate conidial suspension (5 × 106 conidia/ml) and incubated for 10 days at 20 ± 3 °C in 100 % humidity with a 10-h photoperiod. Three healthy seedlings were sprayed with sterile water as a control. After 10 days, dark brown spots developed in the inoculated plants; however, no spots were observed in the controls. Fungi with the same conidial characteristics as Oaa-2 were isolated from the infected plants, and the ITS sequence and the nine nuclear protein-encoding genes of these plant isolates was identical to those of Oaa-2. Pathogenicity tests also were conducted with isolate Oaa-2 with two oat cultivars, Sunyang and Joyang, with the same result. To our knowledge, A. alternata has not been previously reported to cause disease on oats in South Korea, although it does cause economic losses in China (Chen et al. 2020).