Phenotypic characterization and candidate gene analysis of a short kernel and brassinosteroid insensitive mutant from hexaploid oat (Avena sativa)

In an ethyl methanesulfonate oat (Avena sativa) mutant population we have found a mutant with striking differences to the wild-type (WT) cv. Belinda. We phenotyped the mutant and compared it to the WT. The mutant was crossed to the WT and mapping-by-sequencing was performed on a pool of F2 individuals sharing the mutant phenotype, and variants were called. The impacts of the variants on genes present in the reference genome annotation were estimated. The mutant allele frequency distribution was combined with expression data to identify which among the affected genes was likely to cause the observed phenotype. A brassinosteroid sensitivity assay was performed to validate one of the identified candidates. A literature search was performed to identify homologs of genes known to be involved in seed shape from other species. The mutant had short kernels, compact spikelets, altered plant architecture, and was found to be insensitive to brassinosteroids when compared to the WT. The segregation of WT and mutant phenotypes in the F2 population was indicative of a recessive mutation of a single locus. The causal mutation was found to be one of 123 single-nucleotide polymorphisms (SNPs) spanning the entire chromosome 3A, with further filtering narrowing this down to six candidate genes. In-depth analysis of these candidate genes and the brassinosteroid sensitivity assay suggest that a Pro303Leu substitution in AVESA.00010b.r2.3AG0419820.1 could be the causal mutation of the short kernel mutant phenotype. We identified 298 oat proteins belonging to orthogroups of previously published seed shape genes, with AVESA.00010b.r2.3AG0419820.1 being the only of these affected by a SNP in the mutant. The AVESA.00010b.r2.3AG0419820.1 candidate is functionally annotated as a GSK3/SHAGGY-like kinase with homologs in Arabidopsis, wheat, barley, rice, and maize, with several of these proteins having known mutants giving rise to brassinosteroid insensitivity and shorter seeds. The substitution in AVESA.00010b.r2.3AG0419820.1 affects a residue with a known gain-of function substitution in Arabidopsis BRASSINOSTEROID-INSENSITIVE2. We propose a gain-of-function mutation in AVESA.00010b.r2.3AG0419820.1 as the most likely cause of the observed phenotype, and name the gene AsGSK2.1. The findings presented here provide potential targets for oat breeders, and a step on the way towards understanding brassinosteroid signaling, seed shape and nutrition in oats.

Macromolecular characterization of high β-glucan oat lines

Oat (Avena sativa) is a cereal grain rich in fibers, proteins, vitamins and minerals. Oats have been linked to several health benefits, such as lowering blood cholesterol levels, counteracting cardiovascular disease and regulating blood sugar levels. This study aimed to characterize two new oat lines with high β-glucan content emanating from ethyl methyl sulphonate mutagenesis on the Lantmännen elite variety Belinda. Two of the mutated lines, and the mother variety Belinda, were profiled for β-glucan, arabinoxylan, total dietary fiber and starch composition. In addition, total lipid and protein content, amino acid composition and β-glucan molecular weights were analyzed. The high levels of β-glucan resulted in a significant increase in total dietary fiber, but no correlation could be established between higher or lower levels of the assayed macromolecules, i.e., between arabinoxylan-, starch-, lipid- or protein levels in the mutated lines compared to the reference. The results indicate separate biosynthetic pathways for β-glucans and other macromolecules and an independent regulation of the different polysaccharides studied. Therefore, ethyl methyl sulphonate mutagenesis can be used to increase levels of multiple macromolecules in the same line.

Untargeted metabolomics profiling of oat (Avena sativa L.) and wheat (Triticum aestivum L.) infested with wheat stem sawfly (Cephus cinctus Norton) reveals differences associated with plant defense and insect nutrition

Introduction

Wheat stem sawfly (WSS), Cephus cinctus Norton, is a major pest of common bread wheat (Triticum aestivum L.) and other cultivated cereals in North America. Planting of cultivars with solid stems has been the primary management strategy to prevent yield loss due to WSS infestation, however expression of this phenotype can vary depending on environmental conditions and solid stems hinder biological control of WSS via braconid parasitoids Bracon cephi (Gahan) and Bracon lissogaster Muesebeck. In the hollow stems of oat (Avena sativa L.), WSS larvae experience 100% mortality before they reach late instars, but the mechanisms for this observed resistance have not been characterized.

Objective

The objective of this study was to explore additional sources of resistance outside of the historic solid stem phenotype.

Methods

Here, we use an untargeted metabolomics approach to examine the response of the metabolome of two cultivars of oat and four cultivars of spring wheat to infestation by WSS. Using liquid chromatography-mass spectrometry (LC-MS), differentially expressed metabolites were identified between oat and wheat which were associated with the phenylpropanoid pathway, phospholipid biosynthesis and signaling, the salicylic acid signaling pathway, indole-3-acetic acid (IAA) degradation, and biosynthesis of 1,4-benzoxazin-3-ones (Bxs). Several phospho- and galacto- lipids were found in higher abundance in oat, and with the exception of early stem solidness cultivar Conan, both species experienced a decrease in abundance once infested. In all wheat cultivars except Conan, an increase in abundance was observed for Bxs HMDBOA-glc and DIBOA-β-D-glucoside after infestation, indicating that this pathway is involved in wheat response to infestation in both solid and hollow stemmed cultivars. Differences between species in compounds involved in IAA biosynthesis, degradation and inactivation suggest that wheat may respond to infestation by inactivating IAA or altering the IAA pool in stem tissue.

Conclusion

We propose that the species differences found here likely affect the survival of WSS larvae and may also be associated with differences in stem architecture at the molecular level. Our findings suggest pathways to focus on for future studies in elucidating plant response to WSS infestation.

Elevated CO2 Can Improve the Tolerance of Avena sativa to Cope with Zirconium Pollution by Enhancing ROS Homeostasis

Zirconium (Zr) is one of the toxic metals that are heavily incorporated into the ecosystem due to intensive human activities. Their accumulation in the ecosystem disrupts the food chain, causing undesired alterations. Despite Zr's phytotoxicity, its impact on plant growth and redox status remains unclear, particularly if combined with elevated CO2 (eCO2). Therefore, a greenhouse pot experiment was conducted to test the hypothesis that eCO2 can alleviate the phytotoxic impact of Zr upon oat (Avena sativa) plants by enhancing their growth and redox homeostasis. A complete randomized block experimental design (CRBD) was applied to test our hypothesis. Generally, contamination with Zr strikingly diminished the biomass and photosynthetic efficiency of oat plants. Accordingly, contamination with Zr triggered remarkable oxidative damage in oat plants, with concomitant alteration in the antioxidant defense system of oat plants. Contrarily, elevated levels of CO2 (eCO2) significantly mitigated the adverse effect of Zr upon both fresh and dry weights as well as the photosynthesis of oat plants. The improved photosynthesis consequently quenched the oxidative damage caused by Zr by reducing the levels of both H2O2 and MDA. Moreover, eCO2 augmented the total antioxidant capacity with the concomitant accumulation of molecular antioxidants (e.g., polyphenols, flavonoids). In addition, eCO2 not only improved the activities of antioxidant enzymes such as peroxidase (POX), superoxide dismutase (SOD) and catalase (CAT) but also boosted the ASC/GSH metabolic pool that plays a pivotal role in regulating redox homeostasis in plant cells. In this regard, our research offers a novel perspective by delving into the previously unexplored realm of the alleviative effects of eCO2. It sheds light on how eCO2 distinctively mitigates oxidative stress induced by Zr, achieving this by orchestrating adjustments to the redox balance within oat plants.

'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.

Additive screening and formula optimization of microbial inhibitor having disease prevention and growth promotion effects on Avena sativa

In order to develop environment friendly microbial inhibitor that can also control disease and promote oat (Avena sativa) growth, the growth rate method and response surface methodology were used to screen wetting agents, preservatives and protective agents at optimal concentrations in this study. Antagonistic activity of the tested bacterium and cell-free fermentation liquid against pathogenic fungi was evaluated on potato dextrose agar (PDA) substratum plates by dual culture technique. Oxford cup method was used to measure antagonistic reaction between screened bacteria. According to each screened bacteria with 50 mL were mixed and cultured in Luria-bertani (LB) substratum. Additives of Wetting agents, UV-protectors, and preservatives were screened by single factor test on the growth concentration of screened mixed bacteria. Afterwards, the optimal additives and concentrations were screened by Box-Behnken method. The microbial inhibitor was detected according to national standards GB20287-2006 and tested on oat in a pot experiment. The results showed that: (1) Functional bacteria which including Bacillus velezensis and Brevundimonas faecalis had control effects of 50.00% to 83.29% on three pathogenic fungi, and their cell free-fermentation liquid could inhibit the growth of pathogenic fungi from 23.51% to 39.90%; (2) Tween-80 was most suitable as wetting agents for Mix biocontrol bacteria (MBB) with 1.00% mass fraction; Sorbitol was selected as UV protective agents for MBB with 0.50% mass fraction. And methyl paraben was used as a preservative for MBB, with 0.50% mass fraction; (3) The most effective adjuvant contained 14.96 mL/L Tween-80, 5.12 g/L methylparaben and 5.6 g/L sorbitol; and (4) The microbial inhibitor controlled 45.57% of oat root rot and increased plant height, root length and seedling biomass. This study provides a suitable environment for the protection of mixed biocontrol bacteria, and lays a foundation for the prevention and control of oat diseases, the promotion of growth and the improvement of quality.

Genome-wide analysis and expression profiling of glyoxalase gene families in oat (Avena sativa) indicate their responses to abiotic stress during seed germination

Abiotic stresses have deleterious effects on seed germination and seedling establishment, leading to significant crop yield losses. Adverse environmental conditions can cause the accumulation of methylglyoxal (MG) within plant cells, which can negatively impact plant growth and development. The glyoxalase system, which consists of the glutathione (GSH)-dependent enzymes glyoxalase I (GLX1) and glyoxalase II (GLX2), as well as the GSH-independent glyoxalase III (GLX3 or DJ-1), plays a crucial role in detoxifying MG. However, genome-wide analysis of glyoxalase genes has not been performed for one of the agricultural important species, oat (Avena sativa). This study identified a total of 26 AsGLX1 genes, including 8 genes encoding Ni²⁺-dependent GLX1s and 2 genes encoding Zn²⁺-dependent GLX1s. Additionally, 14 AsGLX2 genes were identified, of which 3 genes encoded proteins with both lactamase B and hydroxyacylglutathione hydrolase C-terminal domains and potential catalytic activity, and 15 AsGLX3 genes encoding proteins containing double DJ-1 domains. The domain architecture of the three gene families strongly correlates with the clades observed in the phylogenetic trees. The AsGLX1, AsGLX2, and AsGLX3 genes were evenly distributed in the A, C, and D subgenomes, and gene duplication of AsGLX1 and AsGLX3 genes resulted from tandem duplications. Besides the core cis-elements, hormone responsive elements dominated the promoter regions of the glyoxalase genes, and stress responsive elements were also frequently observed. The subcellular localization of glyoxalases was predicted to be primarily in the cytoplasm, chloroplasts, and mitochondria, with a few presents in the nucleus, which is consistent with their tissue-specific expression. The highest expression levels were observed in leaves and seeds, indicating that these genes may play important roles in maintaining leaf function and ensuring seed vigor. Moreover, based on in silico predication and expression pattern analysis, AsGLX1-7A, AsGLX2-5D, AsDJ-1-5D, AsGLX1-3D2, and AsGLX1-2A were suggested as promising candidate genes for improving stress resistance or seed vigor in oat. Overall, the identification and analysis of the glyoxalase gene families in this study can provide new strategies for improving oat stress resistance and seed vigor.

Genome-Wide Identification of NAC Gene Family and Expression Analysis under Abiotic Stresses in Avena sativa

In this study, a total of 177 NAC members were identified in Avena sativa, located on 21 chromosomes. Phylogenetic analysis showed that AsNAC proteins could be divided into seven subfamilies (I-VII), and that proteins in the same subfamily have similar protein motifs. Gene structure analysis found that NAC introns ranged from 1 to 17. Cis-element analysis of the promoter indicated that the gene family may have stress-related elements and growth regulation elements. Through qRT-PCR experiments, we speculated that AsNACs genes can respond to abiotic stresses such as cold, freezing, salt, and saline alkali. This study provides a theoretical basis for further exploring the function of the NAC gene family in A. sativa.

The convergent application of metabolites from Avena sativa and gut microbiota to ameliorate non-alcoholic fatty liver disease: a network pharmacology study

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a serious public health issue globally, currently, the treatment of NAFLD lies still in the labyrinth. In the inchoate stage, the combinatorial application of food regimen and favorable gut microbiota (GM) are considered as an alternative therapeutic. Accordingly, we integrated secondary metabolites (SMs) from GM and Avena sativa (AS) known as potent dietary grain to identify the combinatorial efficacy through network pharmacology.

METHODS

We browsed the SMs of AS via Natural Product Activity & Species Source (NPASS) database and SMs of GM were retrieved by gutMGene database. Then, specific intersecting targets were identified from targets related to SMs of AS and GM. The final targets were selected on NAFLD-related targets, which was considered as crucial targets. The protein-protein interaction (PPI) networks and bubble chart analysis to identify a hub target and a key signaling pathway were conducted, respectively. In parallel, we analyzed the relationship of GM or AS─a key signaling pathway─targets─SMs (GASTM) by merging the five components via RPackage. We identified key SMs on a key signaling pathway via molecular docking assay (MDA). Finally, the identified key SMs were verified the physicochemical properties and toxicity in silico platform.

RESULTS

The final 16 targets were regarded as critical proteins against NAFLD, and Vascular Endothelial Growth Factor A (VEGFA) was a key target in PPI network analysis. The PI3K-Akt signaling pathway was the uppermost mechanism associated with VEGFA as an antagonistic mode. GASTM networks represented 122 nodes (60 GM, AS, PI3K-Akt signaling pathway, 4 targets, and 56 SMs) and 154 edges. The VEGFA-myricetin, or quercetin, GSK3B-myricetin, IL2-diosgenin complexes formed the most stable conformation, the three ligands were derived from GM. Conversely, NR4A1-vestitol formed stable conformation with the highest affinity, and the vestitol was obtained from AS. The given four SMs were no hurdles to develop into drugs devoid of its toxicity.

CONCLUSION

In conclusion, we show that combinatorial application of AS and GM might be exerted to the potent synergistic effects against NAFLD, dampening PI3K-Akt signaling pathway. This work provides the importance of dietary strategy and beneficial GM on NAFLD, a data mining basis for further explicating the SMs and pharmacological mechanisms of combinatorial application (AS and GM) against NAFLD.

First Report of Sharp Eyespot of Oat (Avena sativa) Caused by Ceratobasidium cereale in Korea

Along with barley and wheat, oats (Avena sativa) are cultivated as winter crops in Korea, and the total area for oat cultivation is 103 ha in 2021. From late March to early April 2021, sharp eyespot symptoms on oat (cv. Choyang) leaf sheaths and straws were observed in two commercial fields located in Haenam (N34°38'35.04588/E126°38'31.00668) and Gangjin (N34°38'9.46788/E126°37'19.44984), Jeollanam-do, Korea. The incidence was 5% and 7%, respectively. Small brown spots were irregular circles that began to appear on the lower sheaths, and the spots gradually enlarged in the upper part of the sheaths. The center of each lesion turned whitish-brown with dark brown margins, resulting in a blight of the sheaths. Three plants displaying typical sharp eyespot lesions were collected from each of two individual regions, Haenam and Gangjin. To isolate the causal pathogen, two infected tissues (5  5 mm) from the collected plants were surface-sterilized by treating them with 70% ethanol for 1 min and 1% NaClO for 1 min immediately after being treated with 95% ethanol for 1 min. Subsequently, the samples were rinsed three times with distilled water, dried with sterile filter paper, transferred to 1.5% water agar supplemented with 100 ppm streptomycin, and then incubated in the dark at 25°C. Hyphae emerging from the randomly selected three independent tissues from each location were subcultured on potato dextrose agar (PDA, Sparks, MD 21152, USA), resulting in three independent isolates (HNO-1, HNO-2, HNO-3) from Haenam and three (KJO1-1, KJO1-2, KJO1-3) from Ganjin after single-hypha-tip purification. Colonies on the PDA were pigmented white at first and subsequently changed to light brown after 2 weeks. All collected isolates formed globose and irregular dark brown to black sclerotia on PDA after 2 weeks. Binuclear hyphae were white to dark brown in color, branched at right angles with a septum near the branch, and multinucleate cells, suggesting that these isolates belonged to Ceratobasidium cereale (Boerema et al., 1977; Burpee, 1980; Sharon et al.,2008). For molecular identification, the ITS (GenBank accession nos. MW691851-53 for HNO-1 to HNO-3; MW691857-59 for KJO1-1 to KJO1-3), LSU (OQ397530-35), rpb2 (OQ409878-83), tef1 (OQ409884-89), and atp6 (OQ409890-95) regions of six isolates were amplified using the primer pairs ITS4/5 (White et al., 1990), LROR/LR5 (Vilgalys and Hester, 1990), bRPB2-6F/bRPB2-7.1R (Matheny, 2005; Reeb et al., 2004), TEF1-F/TEF1-R (Litvintseva et al., 2006), and ATP61/ATP62 (Kretzer and Bruns, 1999), respectively. The sequences of ITS region showed 99.7% identity with C. cereale strain WK137-56 (KY379365) and 99.8% with Ceratobasidium sp. AG-D (KP171639). Using the MEGA X program (Kumar et al. 2018), a maximum likelihood phylogenetic analysis based on the concatenated ITS-LSU, rpb2, tef1 and atp6 sequences placed the six isolates within a clade comprising C. cereale (Gónzalez et al.,2016; Ji et al., 2017; Tomioka et al., 2021; Li et al., 2014). Two representative isolate, HNO-1 and KJO1-1, were deposited in the Korean Agriculture Culture Collection (Accession No. KACC 49887 and 410268, respectively). For pathogenicity, the six isolates were cultured on sterilized ray grains at 25°C in the dark for 3 weeks as the inoculum. Five oat (cv. Choyang) seeds were sown per pot containing 80 g of the infected ray grains mixed with 150 g of composite soil and 150 ml of water (Baroker Garden Soil, Seoul Bio Co., LTD). The control was treated with 80 g of the sterilized ray grains mixed with 150 g of composite soil and 150 ml of water. All inoculated and control pots were placed in a 20°C growth chamber with a 12-h photoperiod and 65% humidity. Typical sharp eyespot symptoms were observed on the oat sheath of seedlings three weeks post-inoculation. No symptoms were observed in the control seedlings. The infection assays were repeated thrice, with similar results. The pathogen was successfully re-isolated, and its identity was confirmed via morphological and molecular analyses. In Korea, few etiological studies have been conducted on oats because they are less economical than barley and wheat. Sharp eyespot disease caused by C. cereale has already been reported in barley and wheat (Kim et al., 1991); however, this is the first report of this disease in oats in Korea.

Effect of Avena sativa (Oats) on cognitive function: A systematic review of randomized controlled trials

BACKGROUND AND AIM

The effect of polyphenol-rich diets or supplements on cognitive function remains a contentious topic. The objective of this study was to investigate the effects of Avena sativa (oat extracts) on cognitive function among healthy adults.

METHODS

A structured literature search was undertaken using PubMed, Web of Science, and Scopus from the database's establishment until March 17, 2022. Data on cognitive function, regarding accuracy and speed of performance, were gathered from randomized controlled trials (RCTs) that investigated the acute or chronic effects of Avena sativa in healthy subjects. The Cochrane Collaboration risk-of-bias tool was used to assess the quality of included studies.

RESULTS

We included six RCTs, of which three were crossover designs, with a total of 287 individuals. Four studies investigated the acute effect of Avena sativa, while two investigated its chronic effect. Acute ingestion of Avena sativa appeared to positively influence the accuracy and speed of performance. While short-term chronic supplementation resulted in a significant improvement in cognitive function, long-term chronic supplementation did not. Overall, the evidence was of average quality.

CONCLUSION

Acute supplementation with Avena sativa may improve cognitive function in healthy volunteers. Given the small number of trials included and the disparity of the intervention dose, the conclusions of this study should be interpreted with caution. More high-quality, long-term studies are warranted.

The separate effects of whole oats and isolated beta-glucan on lipid profile: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND & AIMS

It is well known that dietary fiber positively impacts the microbiome and health as a whole. However, the health effects of β-glucan, a dietary fiber extracted from oats, have been questioned when administered alone or incorporated into other foods. The purpose of this systematic review and meta-analysis was to evaluate the impact of oats or β-glucan supplements on the lipid profile.

METHODS

Randomized controlled trials with parallel-arm or crossover blinded interventions at least two weeks in duration, for hyperlipidemic or non-hyperlipidemic men and women ≥18 years of age were selected. Only single (participants blinded) or double-blinded studies that compared oat or isolated β-glucan with a placebo/control group were considered for this review. The databases EMBASE, PubMed, Web of science and CINHAL were searched, from the earliest indexed year available online to the end of January 2022. Random-effects models were used to combine the estimated effects extracted from individual studies, and data were summarized as standardized mean difference (SMD) and 95% confidence interval (95%CI).

RESULTS

A total of 811 articles were screened for eligibility, and relevant data were extracted from 28 studies, totaling 1494 subjects. Oat interventions TC (-0.61, 95%CI: -0.84;-0.39, p < 0.00001, and -0.70, 95%CI: -1.07;-0.34, p = 0.0002, respectively) and LDL (-0.51, 95%CI: -0.71;-0.31, p < 0.00001, and -0.38, 95%CI: -0.60;-0.15, p = 0.001, respectively). Moreover, isolated β-glucan interventions from parallel-arm studies decreased TC (-0.73, 95%CI: -1.01;-0.45, p < 0.00001), LDL (-0.58, 95%CI: -0.85;-0.32, p < 0.0001) and triglycerides (-0.30, 95%CI: -0.49;-0.12, p = 0.001). HDL was not altered by either oat or isolated β-glucan (p > 0.05).

CONCLUSION

Overall, this review showed that both oat and isolated β-glucan interventions improved lipid profiles. Furthermore, the ingestion of oats or isolated β-glucan supplements are effective tools to combat dyslipidemia and should be considered in cardiovascular disease prevention.

Management of Reniform Nematode in Cotton Using Winter Crop Residue Amendments Under Greenhouse Conditions

Rotylenchulus reniformis (reniform nematode, RN) is among the most important nematodes affecting cotton. Cultural practices, such as rotation and soil amendment, are established methods for managing RN. Management may be enhanced if crop residue has biofumigant properties against RN. The objective was to evaluate the efficacy of winter crop amendments for managing RN in the greenhouse. Reniform nematode-infested soil was amended with dry or fresh organic matter (OM, 2% w/w) from winter crops - canola, carinata, hairy vetch, oat, or no crop. Cotton was subsequently grown in this soil. Independent of the crop, dry OM amendments were more effective than no amendment at managing RN, while fresh OM amendments were not. Soil and root RN abundances and reproduction factors were generally lower in Trials 1 and 3 for dry OM than fresh OM amendments or control without OM. In Trial 2, none of the OM treatments reduced RN parameters compared with no OM control. In general, when compared to plants without RN or OM, RN did not produce significant changes in growth parameters but did affect physiology (Soil Plant Analysis Development, or SPAD, values). In conclusion, dry OM amendments can help manage RN, crop growth does not always relate to RN abundances, and SPAD values could help indicate RN presence.

Reniform Nematode Management Using Winter Crop Rotation and Residue Incorporation Methods in Greenhouse Experiments

Rotylenchulus reniformis (reniform nematode, RN) is an important pathogen in cotton production. Cultural practices such as crop rotation and biofumigation-management of soil pathogens by biocidal compounds from crop residues-may help manage RN. The objective of this study was to evaluate the efficacy of winter crops for RN management through combinations of rotation and crop residue incorporation in a cotton greenhouse experiment. A total of 10 treatments were evaluated in soil inoculated with RN: three winter crops (carinata, oat, or hairy vetch) grown in rotation with no shoot organic matter (OM) incorporated (1-3), fresh shoot OM incorporated (4-6), or dry shoot OM incorporated (7-9), and a fallow control (10). Roots were re-incorporated in all treatments except fallow. Subsequently, cotton was grown. Oat and fallow were better rotation crops to lower soil RN abundances at winter crop termination than hairy vetch and carinata. After the OM incorporation treatments and cotton growth, oat was generally more effective at managing RN in cotton than carinata or hairy vetch. Within each crop, incorporation treatment generally did not affect RN management. Cotton growth was not consistently affected by the treatments.

First Report of Brown Leaf Spot Caused by Epicoccum tobaicum on Oat (Avena sativa) in Korea

Oat (Avena sativa) is one of the Korean winter crops, and oat consumption has been increasing because it is widely perceived as a superfood. Recently, various fungal diseases have been reported likely due to climate changes during the winter season in Korea (Choi et al., 2018; Kim, 2020). During the 2020-2021 winter to spring, we surveyed new fungal diseases among cereals, including oats, in the southern region of Korea. In April 2021, brown leaf spots on oat leaves were observed in Gangjin, Jeollanam-do, Korea. These brown spots were irregular circles, ranging from 2-7 mm in diameter. Samples from three infected leaves were surface sterilized by treating them with 70% ethanol for 1 min and 1% NaOCl for 1 min. The samples were subsequently rinsed at least twice with distilled water and dried with a sterile paper towel before being placed on 1.5% water agar supplemented with 100 ppm streptomycin. Hyphal tips derived from infected tissues after incubation at 25C for 7 days were transferred to a fresh potato dextrose agar (PDA). Three isolates, labeled as KJO-AN2-S1, KJO-AN2-S2 and KJO-AN2-S3, were obtained via single hyphal tip purification. Colonies on PDA were pigmented vermilion and subsequently turned to saffron color with irregular margins after 7 days. Conidia produced on PDA were golden to dark brown, globose to subglobose, solitary, and measured 15.5-21.5 μm in diameter (n=50). Cultural and morphological characteristics suggested that these isolates belong to Epicoccum species (Chen et al. 2017). For identification by sequencing, the ITS (MW691866-68), tub2 (MW691872-74), and rpb2 (MW691869-71) regions of three isolates were amplified using the primer pairs ITS5/ITS4 (White et al., 1990), Btub2Fd/ Btub4Rd (Woudengerg et al., 2009), and RPB2-5F2 (Sung et al., 2007)/fRPB2-7cR (Liu et al., 1999), respectively. A maximum likelihood phylogenetic analysis based on the concatenated ITS, tub2, and rpb2 sequences placed the three isolates within a clade comprising E. tobaicum CBS 384.36. A mycelial plug (5 mm diameter) was inoculated onto wounded and unwounded leaves of healthy 12-day-old oat (cv. Choyang) seedlings. The control leaves were inoculated with a sterile PDA plug. All inoculated and control plants were placed in a plastic box and incubated at 20℃ in darkness with 100% humidity. After 1 day, the inoculated mycelial plug or sterile PDA plug from plants was removed; the plants in plastic boxes were then transferred to a growth chamber set at 20℃ with 12 h light and 60-70% humidity. While brown spot lesions were observed in both unwounded and wounded leaves 7 days post-inoculation, both wounded and unwounded control leaves remained asymptomatic. The pathogen was recovered from all symptomatic leaf tissues but could not be isolated from control leaves. The re-isolated pathogen was identified as E. tobaicum through morphological characterization and sequence-based identification, fulfilling Koch's postulates. This study is the first to report a causal relationship between E. tobaicum and brown leaf spot disease of oat in Korea. Identification of this newly emerging fungal disease on oats will help prepare for effectively managing this disease.

Structural Analysis and Anti-Inflammatory Effect of a Digalactosyldiacylglycerol-Monoestolide, a Characteristic Glycolipid in Oats

Digalactosyldiacylglycerol- (DGDG-) monoestolide is a characteristic glycolipid in oats. DGDG-monoestolides possess a unique structure whereby a fatty acid of DGDG is replaced by a fatty acid ester of hydroxy fatty acid (FAHFA). While the physiological effects of DGDG and FAHFA have been reported previously, the effects of DGDG-monoestolides are unknown. Hence, we isolated a major DGDG-monoestolide molecular species from oats, analyzed its structure, and evaluated its anti-inflammatory effect. Based on GC-MS, MS/MS, and NMR analyses, the isolated compound was identified as a DGDG-monoestolide that contains the linoleic acid ester of 15-hydroxy linoleic acid (LAHLA) and linoleic acid (i.e., DGDG-LAHLA). The isolated DGDG-LAHLA was evaluated for its anti-inflammatory effect on LPS-stimulated RAW264 cells. The production of nitric oxide and cytokines (IL-6, TNF-α, and IL-10) were significantly decreased by DGDG-LAHLA, suggesting the anti-inflammatory effect of DGDG-LAHLA for the first time. In addition, our data showed a pronounced uptake of DGDG-LAHLA by cells. Some compounds corresponding to the predicted DGDG-LAHLA metabolites were also detected, suggesting that both intact DGDG-LAHLA and its metabolites may contribute to the above anti-inflammatory activities. These results are expected to expand the availability of oats as a functional food.

The potential curative role of Avena sativa extract against oxidative stress, DNA damage and apoptosis induced by acute hepatotoxicity of silver nanoparticles in rats

Silver nanoparticles (Ag NPs or nanosilver) have pulled in expanding interest because of their novel physical, substance, and organic properties contrasted with their full scale scaled partners. The goal of this study was to investigate if Avena sativa (AVS) extract could ameliorate Ag NPs toxicity-induced alterations in liver structure and function, DNA damage, apoptosis, and oxidative stress. Twenty adult male rats were assigned randomly to four groups: control, AVS (intragastrically, 5 g/Kg body weight/day) for 2 weeks, Ag NPs (400 mg/kg body weight/day) for 1 week as acute toxicity and Ag NPs + AVS (same therapy of Ag NPs as acute toxicity with AVS). This study demonstrated a statistical significant increase in serum levels of liver function tests (AST, ALT, ALP and globulin), liver DNA damage, apoptotic P53 and Malondialdehyde after Ag NPs administration when compared to control group. Conversely, statistical significant decreases were detected in serum albumin, total proteins, liver reduced glutathione, catalase, superoxide dismutase, glutathione S-transferase and anti-apoptotic Bcl₂ in Ag NPs group as compared to control group. Interestingly, treatment of Ag NPs with AVS (Ag Nps + AVS) was associated with significant improvements of the studied parameters, liver structure and functions. Avena sativa (AVS) extract could scavenge free radicals producing beneficial effects against acute Ag NPs hepatotoxicity in rats induced through activation of oxidative stress and apoptosis.

Effects of Avena sativa and Glycyrrhiza glabra Leaves Extracts on Immune Responses in Serum Cytokine and Liver Enzyme Levels in NIH Mice

In addition to their high quantities of active chemicals, medicinal plants are well-known for their pharmacological qualities, which include immunological modulation. T Consequently, this study aimed to examine the effects of Avena sativa and Glycyrrhiza glabra leaf extracts on immunological responses as measured by blood cytokine and liver enzyme levels. The phytochemical analysis of Avena sativa crude leaf extracts revealed the presence of alkaloids,flavonoids, tannins, phenolic compounds, and saponins but the absence of resins and violet oils. On the other hand, violet oils, flavonoids, tannins, saponins, and glycosides were detected in significant concentration in Glycyrrhiza glabra ethanolic extract, although resins and phenolic compounds were not present. Fifty male NIH mice were randomly divided into five groups: Except for the control group, all animals were given subcutaneously and orally with extracts (50 mg/kg) for 14 days prior to LPS-induced (1 mg/kg body weight) liver injury. LPS-induced liver damage was induced on day 15, and mice were starved.Group 1 was injected subcutaneously with normal saline as a control. Group 2 received an injection of 100 l of crude oat extract subcutaneously. Group 3 was administered 100 l (50 mg/kg) of crude Oat extract orally. Group 4: administered 100 l (50 mg/kg) of crude Licorice extract subcutaneously. Group 5 ingested 100 l (50 mg/kg) of crude Licorice extract orally. IL-4 levels were significantly elevated (P< 0.05) in the subcutaneously and orally treated groups compared to the control group (12.3 0.23 pg/ml). IL-6 was significantly elevated (P<0.05) in mice given subcutaneously or orally with Avena sativa or Glycyrrhiza glabra extracts compared to mice treated subcutaneously or orally with a control substance (44 0.57 pg/ml). The concentration of TNF- was significantly elevated (P<0.05) in subcutaneous and oral treated groups (283.6 1.7 and 280.6 12.2; 233.9 0.6 and 241.2 2.8) compared with the control group (130 0.42) pg/ml. When mice were exposed to LPS-containing extracts, both GOT, and GPT levels fell relative to the control group.

Isolation and Characterization of a Novel Pathogenesis-Related Protein-1 Gene (AvPR-1) with Induced Expression in Oat (Avena sativa L.) during Abiotic and Hormonal Stresses

Pathogenesis-related protein-1 (PR-1) plays crucial roles in regulating plant responses to biotic and abiotic stresses. This study aimed to isolate and characterize the first PR-1 (AvPR-1) gene in oat (Avena sativa L.). AvPR-1 presented conserved signal peptide motifs and core amino acid composition in the functional protein domains as the protein sequence of AvPR-1 presented 98.28%, 97.7%, and 95.4% identity with known PR1 proteins isolated from Triticum aestivum PRB1-2-like, Triticum dicoccoides PRB1-2-like, and Aegilops tauschii subsp. tauschii, respectively. Bioinformatic analysis showed that the AvPR-1 protein belongs to the CAP superfamily (PF00188). Secondary and 3D structure analyses of the AvPR-1 protein were also conducted, confirming sequence conservation of PR-1 among studied species. The AvPR-1 protein harbors a calmodulin-binding domain located in its C-terminal part as previously shown for its wheat homolog TdPR1.2. Moreover, gene expression analysis showed that AvPR-1 was induced in response to many abiotic and hormonal stresses especially in leaves after treatment for 48 h. This is the first study exhibiting the expression profiles of the AvPR-1 gene under different stresses in oat.

Ecotoxicological effects of per- and polyfluoroalkyl substances (PFAS) and of a new PFAS adsorbing organoclay to immobilize PFAS in soils on earthworms and plants

A novel adsorptive organoclay (Intraplex A®) was developed for the in situ immobilization of per- and polyfluoroalkyl substances (PFAS) in the vadose zone. We provide the first evaluation of the effects of Intraplex A® on earthworms and plants in a PFAS-contaminated soil. Ecotoxicological tests were carried out on control soil with and without Intraplex A® (C + I and C, respectively) and PFAS-contaminated soil with and without Intraplex A® (PFAS + I and PFAS, respectively). We investigated the acute ecotoxicological effects of PFAS and Intraplex A® on the growth, reproduction and survival of earthworms (Eisenia fetida) and on plant growth (oat - Avena sativa and turnip - Brassica rapa L. silvestris). Earthworm lethality was 7.6 lower in PFAS + I than in PFAS soil. Earthworms avoided 100% C + I and PFAS + I soils, and reduced earthworms' reproduction was observed in both these soils. For both plant species, the PFAS + I soil yielded less fresh and dry shoot biomass than the PFAS soil, while root growth remained unaffected (all tests: p < 0.05). Soils with Intraplex A® had some negative effects on plants and earthworms, which must be balanced with its benefits as an in situ PFAS adsorbent.

Ameliorative and Antioxidative Potential of Lactobacillus plantarum-Fermented Oat (Avena sativa) and Fermented Oat Supplemented with Sidr Honey against Streptozotocin-Induced Type 2 Diabetes in Rats

The ameliorative and antioxidative stress effects of probiotic-enriched fermented oat (FOE) or fermented oat with honey (HFOE) extracts on streptozotocin-induced diabetes in rats were examined. The total phenolic content (TPC) and antioxidant activity (AOA) were increased in FOE and HFOE after 72 h of fermentation, and γ-aminobutyric acid (GABA) reached 7.35 mg 100 g^-1 in FOE and 8.49 mg 100 g^-1 in HFOE. The β-glucan levels were slightly decreased to 2.45 g 100 g^-1 DW in FOE and 2.63 g 100 g^-1 DW in HFOE. The antidiabetic and hypolipidemic properties of FOE and HFOE were studied in a designed animal model with seven treated groups for 6 weeks. Groups were treated as follows: group 1 (negative group, NR) and group 2 (diabetic rats, DR) were administered 7 mL distilled water orally per day; group 3 (DR + MET) rats were orally administered 50 mg standard drug Metformin kg^-1 daily; group 4 (DR + FOE1) diabetic rats were orally administered 3.5 mL FOE daily; group 5 (DR + FOE2) rats were orally administered 7 mL FOE daily; group 6 (DR + HFOE1) rats were orally administered 3.5 mL HFOE daily; and group 7 (DR + HFOE2) rats were orally administered 7 mL HFOE daily. The HFOE at the high dose had a synergistic effect, lowering random blood glucose (RBG) and fasting blood glucose (FBG). The hypolipidemic potential of HFOE at the high dose was indicated by significant reductions in triglycerides (TG), total cholesterol (CHO), high- and low-density lipoproteins (HDL and LDL), and very-low-density lipoproteins (VLDL). In addition, 7 mL of HFOE improved liver and kidney function more effectively than other fermented extracts or Metformin. As well as the antioxidant enzyme activity, reduced glutathione (GSH), catalase (CAT), superoxide dismutase (SOD), and malonaldehyde (MDA) were significantly enhanced after the administration of HFOE at 7 mL by 68.6%, 71.5%, 55.69%, and 15.98%, respectively, compared to the DR group. In conclusion, administration of L. plantarum-fermented oats supplemented with honey demonstrated antidiabetic effects and a potential approach for controlling glucose levels and lipid profiles, and protecting against oxidative stress.

Effect of a cover crop on the aphid incidence is not explained by increased top-down regulation

Background

Cover crops can be used as a habitat management strategy to enhance the natural enemies and their temporal synchronization with a target pest. We examined the effect of winter oat intercropping within organic plum orchards on the natural enemy abundance and seasonal dynamics on the biological control of plum aphids in spring in Central Chile.

Methods

We compared the incidence and abundance of natural enemies and aphid pests from winter to the end of spring using two treatments: (1) plum trees with an oat cover crop (OCC) and (2) plum trees without a cover crop but with spontaneous vegetation (SV). We hypothesized that cover crops allow the development of winter cereal aphids, promoting the early arrival of natural enemies in spring, resulting in an earlier control of plum aphids.

Results

Winter cereal aphids developed well on the OCC, and as a result, a lower plum aphid incidence in spring was observed when compared to the SV. However, the abundance of natural enemies and the parasitism rates cannot explain the positive impacts of the oat cover crop on the aphid populations as there were no differences between treatments. A potential effect of the oat due to chemical and/or physical stimuli (bottom-up effects) could help to explain these results.

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.

Long-term nitrogen enrichment mediates the effects of nitrogen supply and co-inoculation on a viral pathogen

Host nutrient supply can mediate host-pathogen and pathogen-pathogen interactions. In terrestrial systems, plant nutrient supply is mediated by soil microbes, suggesting a potential role of soil microbes in plant diseases beyond soil-borne pathogens and induced plant defenses. Long-term nitrogen (N) enrichment can shift pathogenic and nonpathogenic soil microbial community composition and function, but it is unclear if these shifts affect plant-pathogen and pathogen-pathogen interactions. In a growth chamber experiment, we tested the effect of long-term N enrichment on infection by Barley Yellow Dwarf Virus (BYDV-PAV) and Cereal Yellow Dwarf Virus (CYDV-RPV), aphid-vectored RNA viruses, in a grass host. We inoculated sterilized growing medium with soil collected from a long-term N enrichment experiment (ambient, low, and high N soil treatments) to isolate effects mediated by the soil microbial community. We crossed soil treatments with a N supply treatment (low, high) and virus inoculation treatment (mock-, singly-, and co-inoculated) to evaluate the effects of long-term N enrichment on plant-pathogen and pathogen-pathogen interactions, as mediated by N availability. We measured the proportion of plants infected (i.e., incidence), plant biomass, and leaf chlorophyll content. BYDV-PAV incidence (0.96) declined with low N soil (to 0.46), high N supply (to 0.61), and co-inoculation (to 0.32). Low N soil mediated the effect of N supply on BYDV-PAV: instead of N supply reducing BYDV-PAV incidence, the incidence increased. Additionally, ambient and low N soil ameliorated the negative effect of co-inoculation on BYDV-PAV incidence. BYDV-PAV infection only reduced chlorophyll when plants were grown with low N supply and ambient N soil. There were no significant effects of long-term N soil on CYDV-RPV incidence. Soil inoculant with different levels of long-term N enrichment had different effects on host-pathogen and pathogen-pathogen interactions, suggesting that shifts in soil microbial communities with long-term N enrichment may mediate disease dynamics.

Resistance of oat breeding lines to grain contamination with Fusarium langsethiae and T-2/HT-2 toxins

Fusarium disease of oats reduces yield quality due to decreasing germination that is caused by the contamination of grain with mycotoxins produced by Fusarium fungi. The aim of this study was to characterize the resistance of naked breeding lines of oats to fungal grain infection and to contamination with T-2 and HT-2 toxins. Thirteen naked oat breeding lines and two naked varieties, Nemchinovsky 61 and Vyatskiy, as well as a husked variety Yakov, were grown under natural conditions in the Nemchinovka Federal Research Center in 2019-2020. The contamination of grain with fungi was determined by the mycological method and real-time PCR. The analysis of mycotoxins was carried out by ELISA. In oats, Alternaria (the grain infection was 15-90 %), Cochliobolus (1-33 %), Cladosporium (1-19 %), Epicoccum (0-11 %), and Fusarium (3-17 %) fungi prevailed in the grain mycobiota. The predominant Fusarium species were F. poae (its proportion among Fusarium fungi was 49-68 %) and F. langsethiae (29-28 %). The highest amounts of F. langsethiae DNA ((27.9-71.9) × 10-4 pg/ng) and T-2/HT-2 toxins (790-1230 μg/kg) were found in the grain of husked oat Yakov. Among the analysed naked oat lines, the amount of F. langsethiae DNA varied in the range of (1.2-42.7) × 10-4 pg/ng,and the content of T-2/HT-2 toxins was in the range of 5-229 μg/kg. Two oat breeding lines, 54h2476 and 66h2618, as well as a new variety, Azil (57h2396), can be characterized as highly resistant to infection with Fusarium fungi and contamination with mycotoxins compared to the control variety Vyatskiy.

and Their Cytotoxic Activity

Twelve steroidal glycosides (1-12) were isolated from the aerial parts of Avena sativa L. (Poaceae). Among the isolated compounds, 1 was directly isolated from the plant for the first time, and 2-6 were new steroidal glycosides. The structures of 1-6 were determined by analysis of their spectroscopic data, chemical transformations, and chromatographic and spectroscopic analyses of the hydrolyzed products. Compounds 5 and 6 were novel steroidal glycosides with a B-ring contracted skeleton (B-nor steroid). Compounds 1, 9, 11, and 12 were cytotoxic to HL-60 human promyelocytic leukemia cells, MIA PaCa-2 human pancreatic carcinoma cells, and A549 human lung adenocarcinoma cells with IC₅₀ values ranging from 0.79 to 13.5 μM. HL-60 cells treated with 1 exhibited apoptotic characteristics, namely, condensed nuclear chromatin, accumulation of sub-G1 cells, and activation of caspase-3. Additionally, the loss of the mitochondrial membrane potential and the release of cytochrome c into the cytoplasm in 1-treated HL-60 cells suggested that 1 induced apoptosis through a mitochondrial-dependent apoptotic pathway.

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.

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.

Specific biotests to assess eco-toxicity of biodegradable polymer materials in soil

Eco-toxicity investigation of polymer materials was considered extremely necessary for their potential menace, which was widely use as mulching materials in agricultural. In this study, polyethylene (PE), polystyrene (PS) and synthetic biomaterials-Ecoflex and cellulose were applying into soil cultivated with two potential indicator plants species: oat (Avena sativa) and red radish (Raphanus sativum). Variety of chemical, biochemical parameters and enzyme activity in soil were proved as effective approach to evaluate polymers phytotoxicity in plant-soil mesocosm. The F-value of biomass, pH, heavy metal and electoral conductivity of Raphanus behaved significant different from T0. Significant analysis results indicated biodegradation was fast in PE than PS, besides, heavy metals were dramatically decrease in the end implied the plant absorption may help decrease heavy metal toxicity. The increase value at T2 of Dehydrogenase activity (0.84 higher than average value for Avena & 0.91 higher for Raphanus), Metabolic Index (3.12 higher than average value for Avena & 3.81 higher for Raphanus) means during soil enzyme activity was promoted by biodegradation for its heterotrophic organisms' energy transportation was stimulated. Statistics analysis was carried on Biplot PC1 (24.2% of the total variance), PC2 (23.2% of the total variance), versus PC3 (22.8% of the total variance), which indicated phosphatase activity and metabolic index was significant correlated, and high correlation of ammonium and protease activity. Furthermore, the effects were more evident in Raphanus treatments than in Avena, suggesting the higher sensitivity of Raphanus to polymers treatment, which indicate biodegradation of polymers in Raphanus treatment has produced intermediate phytotoxic compounds.

Synergistic Effect of Methyl Jasmonate and Abscisic Acid Co-Treatment on Avenanthramide Production in Germinating Oats

The oat (Avena sativa L.) is a grain of the Poaceae grass family and contains many powerful anti-oxidants, including avenanthramides as phenolic alkaloids with anti-inflammatory, anti-oxidant, anti-itch, anti-irritant, and anti-atherogenic activities. Here, the treatment of germinating oats with methyl jasmonate (MeJA) or abscisic acid (ABA) resulted in 2.5-fold (582.9 mg/kg FW) and 2.8-fold (642.9 mg/kg FW) increase in avenanthramide content, respectively, relative to untreated controls (232.6 mg/kg FW). Moreover, MeJA and ABA co-treatment synergistically increased avenanthramide production in germinating oats to 1505 mg/kg FW. Individual or combined MeJA and ABA treatment increased the expression of genes encoding key catalytic enzymes in the avenanthramide-biosynthesis pathway, including hydroxycinnamoyl-CoA:hydrocyanthranilate N-hydroxycinnamoyl transferase (HHT). Further analyses showed that six AsHHT genes were effectively upregulated by MeJA or ABA treatment, especially AsHHT4 for MeJA and AsHHT5 for ABA, thereby enhancing the production of all three avenanthramides in germinating oats. Specifically, AsHHT5 exhibited the highest expression following MeJA and ABA co-treatment, indicating that AsHHT5 played a more crucial role in avenanthramide biosynthesis in response to MeJA and ABA co-treatment of germinating oats. These findings suggest that elicitor-mediated metabolite farming using MeJA and ABA could be a valuable method for avenanthramide production in germinating oats.

Ancient and Modern Cereals as Ingredients of the Gluten-Free Diet: Are They Safe Enough for Celiac Consumers?

Celiac disease is an autoimmune disorder that occurs in genetically predisposed individuals after consuming prolamins from some cereals. Although the products available for celiac subjects have increased significantly in quality and quantity over the last few decades, research still focuses on identifying new ingredients to improve the nutritional, sensorial and functional qualities of gluten-free products. In terms of toxicity for people with celiac disease, there is a wide variability between ancient and modern grains. The most contradictory results are related to the role of oats in the gluten-free diet. In order to clarify the role of minor cereals (such as oat) and ancient grains in the diets of celiac patients, this review discusses recent in vitro and in vivo studies performed on those cereals for which the toxicity for celiac subjects is still controversial. According to in vivo studies, selected oat varieties could be tolerated by celiac patients. On the other hands, although some wheat-ancient grains (Triticum monococcum, Triticum aestivum ssp. spelta and Kamut^®) showed a reduced in vitro toxicity, to date, these grains are still considered toxic for celiac patients. Contradictory results underline the importance of studying the safety of "unusual" cereals in more detail.

Metabolomics for Biomarker Discovery: Key Signatory Metabolic Profiles for the Identification and Discrimination of Oat Cultivars

The first step in crop introduction-or breeding programmes-requires cultivar identification and characterisation. Rapid identification methods would therefore greatly improve registration, breeding, seed, trade and inspection processes. Metabolomics has proven to be indispensable in interrogating cellular biochemistry and phenotyping. Furthermore, metabolic fingerprints are chemical maps that can provide detailed insights into the molecular composition of a biological system under consideration. Here, metabolomics was applied to unravel differential metabolic profiles of various oat (Avena sativa) cultivars (Magnifico, Dunnart, Pallinup, Overberg and SWK001) and to identify signatory biomarkers for cultivar identification. The respective cultivars were grown under controlled conditions up to the 3-week maturity stage, and leaves and roots were harvested for each cultivar. Metabolites were extracted using 80% methanol, and extracts were analysed on an ultra-high performance liquid chromatography (UHPLC) system coupled to a quadrupole time-of-flight (qTOF) high-definition mass spectrometer analytical platform. The generated data were processed and analysed using multivariate statistical methods. Principal component analysis (PCA) models were computed for both leaf and root data, with PCA score plots indicating cultivar-related clustering of the samples and pointing to underlying differential metabolic profiles of these cultivars. Further multivariate analyses were performed to profile differential signatory markers, which included carboxylic acids, amino acids, fatty acids, phenolic compounds (hydroxycinnamic and hydroxybenzoic acids, and associated derivatives) and flavonoids, among the respective cultivars. Based on the key signatory metabolic markers, the cultivars were successfully distinguished from one another in profiles derived from both leaves and roots. The study demonstrates that metabolomics can be used as a rapid phenotyping tool for cultivar differentiation.

Changes in the Concentrations of Key Aroma Compounds in Oat (Avena sativa) Flour during Manufacturing of Oat Pastry

Application of the aroma extract dilution analysis on the volatiles isolated from oat flour revealed 30 aroma-active compounds in the flavor dilution (FD) factor range of 2-8192, among which oat-flour-like smelling (E,E,Z)-2,4,6-nonatrienal showed by far the highest FD factor. Quantitation performed by stable isotope dilution assays and a calculation of odor activity values (OAV; ratio of the concentration to odor threshold) of 23 odorants showed an OAV of above 1. Among them, vanillin, (E,E,Z)-2,4,6-nonatrienal, 2-acetyl-1-pyrroline, 3-methylbutanoic acid, and 2-methoxy-4-vinylphenol showed the highest OAVs. In a heated (70 °C for 30 min) oat dough prepared by kneading the oat flour in the presence of sucrose and water, 34 aroma-active compounds were identified, among which 17 compounds appeared with an OAV of ≥1. During frying, the weak cereal-like aroma of the oat flour and the oat dough was changed with the generation of an intense roasty, popcorn-like aroma attribute. A comparison to recently published data on oat pastry prepared by toasting of the same dough showed a clear increase in the overall aroma intensity from flour to pastry, in particular, in the popcorn-like, roasty odor impression. Especially considerable increases in the concentrations of the popcorn-like smelling compounds 2-acetyl-1-pyrroline, 2-acetyl-3,4,5,6- and 2-acetyl-1,4,5,6-tetrahydropyridine, 2-propionyl-1-pyrroline, and 2-acetyl-2-thiazoline were measured. In addition, the concentrations of the Strecker aldehydes 2- and 3-methylbutanal, phenylacetaldehyde, and 3-(methyldithio)propanal were also much increased during the toasting process. In contrast, in line with the overall aroma profile, particularly the concentration of the oat-like smelling compound (E,E,Z)-2,4,6-nonatrienal was decreased during processing. The formation and precursors of the key aroma compounds are discussed.

Characterization of the Key Aroma Compounds in a Freshly Prepared Oat (Avena sativa L.) Pastry by Application of the Sensomics Approach

Oat flour has a weak cereal-like, powdery aroma, which is significantly changed by a thermal process. Application of an aroma extract dilution analysis on a distillate obtained from oat pastry prepared under defined conditions led to the detection of 43 odor-active areas in the flavor dilution (FD) factor range of 2-8192. Among them, 3-(methylthio)propanal (cooked-potato-like), 2-acetyl-1-pyrroline (roasty, popcorn-like), vanillin (vanilla-like), 2-methoxy-4-vinylphenol (clove-like), 1-octen-3-one (mushroom-like), 2-propionyl-1-pyrroline (roasty, popcorn-like), and (E,E,Z)-2,4,6-nonatrienal (oat-like) were identified with the highest FD factors. Nine aroma compounds were identified for the first time in oats or oat products, and (E,E,Z)-2,4,6-decatrienal, also showing an oat-like odor quality, is reported for the first time in foods. Quantitation of the 36 most important compounds by means of stable isotope dilution assays followed by a calculation of odor activity values on the basis of odor thresholds in corn starch revealed 2-acetyl-1-pyrroline, vanillin, the tautomers 2-acetyl-3,4,5,6-tetra-hydropyridine and 2-acetyl-1,4,5,6-tetrahydropyridine, 3-(methylthio)propanal, 2-propionyl-1-pyrroline, and methanethiol as the key aroma-active compounds. An aroma recombinate prepared in odorless oat pastry material containing 30 odorants in the concentrations determined in the oat pastry was able to successfully mimic the overall aroma profile of the original oat pastry.

Molecular characterization and evaluation of the antibacterial activity of a plant defensin peptide derived from a gene of oat (Avena sativa L.)

Plant defensins are a group of small disulfide-rich cationic peptides that exhibit a broad spectrum of antimicrobial activities. In the present study, an antibacterial plant defensin peptide was successfully identified and characterized from the transcriptome of the oat (Avena sativa L.), and called AsDef1. The complete nucleotide sequence of AsDef1 was determined (321 bp) and found to contain an open reading frame (ORF) encoding a peptide of 77 aa with a putative 22 aa signal peptide sequence that addresses the mature defensin to the apoplast. Further in silico analyses revealed that the structure of the identified defensin (AsDef1) consists of the Knot1 functional domain with eight conserved cysteine residues and four disulfide bonds. The highest expression of AsDef1 was observed in the developing seeds of the A. sativa plant. AsDef1 also showed antibacterial activity against both Gram-positive and Gram-negative bacteria. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values ranged from 0.15625 μM to 0.625 μM. In this study, we identified and characterized an antibacterial defensin from A. sativa for the first time. The findings of the present study offer insights that can be used in producing pathogen-resistant transgenic plants and in developing potential antibacterial agents in the future using AsDef1 from A. sativa.

Characterization and antioxidant activity of avenanthramides from selected oat lines developed by mutagenesis technique

From a mutagenized oat population, produced by ethyl methanesulfonate mutagenesis, hulled grains from 17 lines with elevated avenanthramide (AVN) content were selected and their AVN structures, concentrations and antioxidant potentials were determined by HPLC-MS² and HPLC equipped with an on-line ABTS⁺ antioxidant detection system. The data obtained showed qualitative and quantitative differences in the synthesis of AVNs in the different lines, with a total AVN concentration up to 227.5 µg/g oat seed flour in the highest line, compared with 78.2 µg/g seed in the commercial line, SW Belinda. In total, 25 different AVNs were identified with avenanthramide B structures being among the most abundant, and AVN C structures having the highest antioxidant activity. The findings indicate the potential of oat mutagenesis in combination with a high precision biochemical selection method for the generation of stable mutagenized lines with a high concentration of total and/or individual AVNs in the oat seed grain.

Localization of the Stem Rust Resistance Gene Pg2 to Linkage Group Mrg20 in Cultivated Oat (Avena sativa)

Stem rust is an important disease of cultivated oat (Avena sativa) caused by Puccinia graminis f. sp. avenae. In North America, host resistance is the primary strategy to control this disease and is conferred by a relatively small number of resistance genes. Pg2 is a widely deployed stem rust resistance gene that originates from cultivated oat. Oat breeders wish to develop cultivars with multiple Pg genes to slow the breakdown of single gene resistance, and often require DNA markers suited for marker-assisted selection. Our objectives were to (i) construct high density linkage maps for a major oat stem rust resistance gene using three biparental mapping populations, (ii) develop Kompetitive allele-specific PCR (KASP) assays for Pg2-linked single-nucleotide polymorphisms (SNPs), and (iii) test the prediction accuracy of those markers with a diverse panel of spring oat lines and cultivars. Genotyping-by-sequencing SNP markers linked to Pg2 were identified in an AC Morgan/CDC Morrison recombinant inbred line (RIL) population. Pg2-linked SNPs were then analyzed in an AC Morgan/RL815 F₂ population and an AC Morgan/CDC Dancer RIL population. Linkage analysis identified a common location for Pg2 in all three populations on linkage group Mrg20 of the oat consensus genetic map. The most predictive markers were identified and converted to KASP assays for use in oat breeding programs. When used in combination, the KASP assays for the SNP loci avgbs2_126549.1.46 and avgbs_cluster_23819.1.27 were highly predictive of Pg2 status in panel of 54 oat breeding lines and cultivars.

Quantitation and Taste Contribution of Sensory Active Molecules in Oat (Avena sativa L.)

A total of 59 taste-active molecules were quantitated and then rated for their individual taste impact on the basis of dose-over-threshold factors in oat flour (Avena sativa L.). A sensitive high-performance liquid chromatography-tandem mass spectrometry method was developed to quantitate bitter-tasting steroidal and furostanol saponins as well as avenanthramides. Four monoglycerides, five free fatty acids and four saponins were confirmed for the first time to be major contributors to the bitter off-taste of oats, among them 1-linoleoyl-rac-glycerol, 1-stearoyl-rac-glycerol, 1-oleoyl-rac-glycerol, 1-palmitoyl-rac-glycerol, linoleic acid, linolenic acid, oleic acid, palmitic acid, and stearic acid as well as avenacosides A and B and the recently identified furostanosides 3-(O-α-l-rhamnopyranosyl(1→2)-[β-d-glucopyranosyl(1→3)-β-d-glucopyranosyl(1→4)]-β-d-glucopyranosid)-26-O-β-d-glucopyranosyl-(25R)-furost-5-ene-3β,22,26-triol and 3-(O-α-l-rhamnopyranosyl(1→2)-[β-d-glucopyranosyl(1→4)]-β-d-glucopyranosid)-26-O-β-d-glucopyranosyl-(25R)-furost-5-ene-3β,22,26-triol. By means of a stable isotope dilution assay, quantitated avenanthramides 2c, 2p, 2f, 1p, 1c, 1f, and 3f were found in concentrations below their thresholds and, therefore, did not contribute to the bitter sensation of the tested oat flour.

Host nutrition mediates interactions between plant viruses, altering transmission and predicted disease spread

Interactions among co-infecting pathogens are common across host taxa and can affect infectious disease dynamics. Host nutrition can mediate these among-pathogen interactions, altering the establishment and growth of pathogens within hosts. It is unclear, however, how nutrition-mediated among-pathogen interactions affect transmission and the spread of disease through populations. We manipulated the nitrogen (N) and phosphorus (P) supplies to oat plants in growth chambers and evaluated interactions between two aphid-vectored Barley and Cereal Yellow Dwarf Viruses: PAV and RPV. We quantified the effect of each virus on the other's establishment, within-plant density, and transmission. Co-inoculation significantly increased PAV density when N and P supplies were low and tended to increase RPV density when N supply was high. Co-infection increased PAV transmission when N and P supplies were low and tended to increase RPV transmission when N supply was high. Despite the parallels between the effects of among-pathogen interactions on density and transmission, changes in virus density only partially explained changes in transmission, suggesting that virus density-independent processes contribute to transmission. A mathematical model describing the spread of two viruses through a plant population, parameterized with empirically derived transmission values, demonstrated that nutrition-mediated among-pathogen interactions could affect disease spread. Interactions that altered transmission through virus density-independent processes determined overall disease dynamics. Our work suggests that host nutrition alters disease spread through among-pathogen interactions that modify transmission.

Acute and Chronic Effects of Green Oat (Avena sativa) Extract on Cognitive Function and Mood during a Laboratory Stressor in Healthy Adults: A Randomised, Double-Blind, Placebo-Controlled Study in Healthy Humans

Green oat (Avena sativa) extracts contain several groups of potentially psychoactive phytochemicals. Previous research has demonstrated improvements in cognitive function following a single dose of these extracts, but not following chronic supplementation. Additionally, whilst green oat extracts contain phytochemicals that may improve mood or protect against stress, for instance species-specific triterpene saponins, to date this possibility has not been examined. The current study investigated the effects of a single dose and four weeks of administration of a novel, Avena sativa herbal extract (cognitaven^®) on cognitive function and mood, and changes in psychological state during a laboratory stressor. The study adopted a dose-ranging, double-blind, randomised, parallel groups design in which 132 healthy males and females (35 to 65 years) received either 430 mg, 860 mg, 1290 mg green oat extract or placebo for 29 days. Assessments of cognitive function, mood and changes in psychological state during a laboratory stressor (Observed Multitasking Stressor) were undertaken pre-dose and at 2 h and 4 h post-dose on the first (Day 1) and last days (Day 29) of supplementation. The results showed that both a single dose of 1290 mg and, to a greater extent, supplementation for four weeks with both 430 mg and 1290 mg green oat extract resulted in significantly improved performance on a computerised version of the Corsi Blocks working memory task and a multitasking task (verbal serial subtractions and computerised tracking) in comparison to placebo. After four weeks, the highest dose also decreased the physiological response to the stressor in terms of electrodermal activity. There were no treatment-related effects on mood. These results confirm the acute cognitive effects of Avena sativa extracts and are the first to demonstrate that chronic supplementation can benefit cognitive function and modulate the physiological response to a stressor.

Mapping of the Oat Crown Rust Resistance Gene Pc39 Relative to Single Nucleotide Polymorphism Markers

Crown rust, caused by Puccinia coronata f. sp. avenae Eriks. (Pca), is among the most important oat diseases resulting in significant yield losses in many growing regions. A gene-for-gene interaction is well established in this pathosystem and has been exploited by oat breeders to control crown rust. Pc39 is a seedling crown rust resistance gene that has been widely deployed in North American oat breeding. DNA markers are desired to accurately predict the specific Pc genes present in breeding germplasm. The objectives of the study were as follows: (i) to map Pc39 in two recombinant inbred line (RIL) populations (AC Assiniboia/MN841801 and AC Medallion/MN841801) and (ii) to identify single nucleotide polymorphism (SNP) markers for postulation of Pc39 in oat germplasm. Pc39 was mapped to a linkage group consisting of 16 SNP markers, which placed the gene on linkage group Mrg11 (chromosome 1C) of the oat consensus map. Pc39 cosegregated with SNP marker GMI_ES01_c12570_390 in the AC Assiniboia/MN841801 RIL population and was flanked by the SNP markers avgbs_126086.1.41 and GMI_ES15_c276_702, with genetic distances of 1.7 and 0.3 cM, respectively. In the AC Medallion/MN841801 RIL population, similar results were obtained but the genetic distances of the flanking markers were 0.4 and 0.4 cM, respectively. Kompetitive Allele-Specific PCR assays were successfully designed for Pc39-linked SNP loci. Two SNP loci defined a haplotype that accurately predicted Pc39 status in a diverse panel of oat germplasm and will be useful for marker-assisted selection in oat breeding.

Protective effects of Avena sativa against oxidative stress-induced kidney damage resulting from an estrogen deficiency in ovariectomized Swiss mice model

The aim of this study was to evaluate the antioxidant capacity of Avena sativa and to confirm its protective effects on estrogen deficiency in ovariectomized mice (OVX) model. Animals were treated during 21 and 60 days as follows: negative control, positive control treated with oat, ovariectomized, and ovariectomized receiving hormonal or oat treatments, respectively. 21 days post-surgery, our results showed that ovariectomy increases weight gain and urea level in plasma. After 60 days of treatment, OVX showed a gain in weight, high increases in relative kidney weight, plasmatic creatinine, glutathione peroxidase (GPX) activity, and protein oxidation as shown by elevated protein carbonyl (PCO) and advanced oxidation protein products (AOPP) levels. On the other side, a decrease was detected in catalase activity. Meanwhile, no significant changes in urea level, lipid peroxidation, SOD and GSH activity were detected. Conversely, supplementation with oat reduced weight gain, as well as oxidative stress and oxidation protein in the kidney of OVX mice. PRACTICAL APPLICATIONS: In our study, we removed the two ovaries of adult female mice in order to eliminate the essential source of steroid hormones. Deficiency in these sexual hormones, especially estrogen, leads to several physiological and morphological disturbances that are found in post-menopausal women. The gain in weight and oxidative kidney damages were the main health problems detected in ovariectomized animals. This work explored for the first time the use of oat grains as a safe natural remedy to treat all previous health problems and to avoid carcinogenic effects of the menopausal hormone therapy. Owing to its health benefits, this cereal species has recently gained attention as an important source of antioxidants and fibers. Thanks to these two components, it can be able to restore all indicated disturbances. Therefore, this cereal can be very useful in the prevention of obesity and kidney oxidative damage occurring during menopause.

Safety Assessment of Avena sativa (Oat)-Derived Ingredients As Used in Cosmetics

This is a safety assessment of Avena sativa (oat)-derived ingredients. The reported functions of these ingredients in cosmetics include abrasives, antioxidant, skin conditioning agents, absorbents, and bulking agents. The Panel reviewed relevant animal and human data related to these ingredients. Because final product formulations may contain multiple botanicals, each containing the same constituents of concern, formulators are advised to be aware of these constituents and to avoid reaching levels that may lead to sensitization or other toxic effects. The Panel stated that industry should continue to use good manufacturing practices to limit impurities and concluded that all but one of the Avena sativa (oat)-derived ingredients are safe as cosmetic ingredients in the practices of use and concentration described in this safety assessment when formulated to be nonsensitizing; data are insufficient to come to a conclusion of safety for Avena Sativa (Oat) Meristem Cell Extract.

Analysis of glycoside hydrolases from oat (Avena sativa) seedling extract

The abundance and the diversity of oligo- and polysaccharides provide a wide range of biological roles attributed either to these carbohydrates or to their relevant enzymes, i.e., the glycoside hydrolases (GHs). The biocatalysis by these families of enzymes is highly attractive for the generation of products used in potential applications, e.g., pharmaceuticals and food industries. It is thus very important to extract and characterize such enzymes, particularly from plant tissues. In this study, we characterized novel sequences of class I chitinases from seedlings extract of the common oat (Avena sativa L.) using proteomics and sequence-structure-function analysis. These enzymes, which belong to the GH19 family of protein, were extracted from oat and identified using SDS-PAGE, trypsin digestion, LC-MS-MS, and sequence-structure-function analysis. The amino acid sequences of the oat tryptic peptides were used to identify cDNAs from the Avena sativa databases of the expressed sequence tags (ESTs) and transcriptome shotgun assembly (TSA). Based upon the Avena sativa sequences of ESTs and TSA, at least 4 predicted genes that encoded oat class I chitinases were identified and reported. The structural characterization of the oat sequences of chitinases provided valuable insights to the context.

Comparison of the plant growth-promotion performance of a consortium of Bacilli inoculated as endospores or as vegetative cells

The effect of three plant growth-promoting Bacillus strains inoculated either alone or as a consortium was tested on oat (Avena sativa) growth. The bioinoculants were applied as vegetative cells or endospores at low cell densities on the seeds and their effect was tested in sterile in vitro conditions, pot experiments, and a field trial. The in vitro seed germination assay showed that both individual bacterial inocula and bacterial consortia had positive effects on seed germination. Greenhouse pot experiments with sterile and non-sterile soil showed that consortia increased the total dry biomass of oat plants as compared to single strain inoculation and uninoculated controls. However, the positive impact on plant growth was less prominent when the bioinoculated strains had to compete with native soil microbes. Finally, the field experiment demonstrated that the consortium of vegetative cells was more efficient in promoting oat growth than the endospore consortium and the uninoculated control. Moreover, both consortia successfully colonized the roots and the rhizosphere of oat plants, without modifying the overall structure of the autochthonous soil microbial communities.

cultivars to alleviate Cu toxicity

Agronomic strategies as intercropping might be applied to reduce plant-available copper (Cu) in Cu-contaminated soils. Thus, our aim was to characterize two different oat cultivars, Avena sativa L. cv. Fronteira and cv. Perona for their ability to tolerate and/or phytostabilize Cu. Copper toxicity reduced plant biomass of both cultivars. The exudate analysis revealed the presence of phenolic compounds and phytosiderophores, yet with a different pattern between the cultivars: cv. Fronteira showed a Cu-concentration and time-dependent release of phenolic compounds, while cv. Perona down-regulated this release during the second week of treatment. Copper concentration increased linearly in all the tissues analysed with increasing Cu concentration showing yet a different compartmentalization: cv. Fronteira and cv. Perona preferentially accumulated Cu in the apoplasm and symplast, respectively. This higher accumulation of Cu in the apoplasm strongly reduces the available binding sites, leading to a competitive absorption with other macro-and micronutrients (e.g. Ca, Mn, Zn). Furthermore, in both cultivars Cu toxicity led to a significant reduction of shoot phosphorus content. The ionomic profile and compartmentalization of Cu together with the root activities demonstrate the different tolerance mechanism towards Cu toxicity of the two oat cultivars. In particular, cv. Fronteira seems to adopt an exclusion strategy based on accumulating Cu in the apoplasm and on the exudation of phenolic compounds. Thus, this cultivar could reduce the mobility and the consequent soil bioavailability of Cu playing an important role as phytostabilizer plant in intercropping systems in Cu-contaminated vineyards or orchards.

Heavy metal content in the green fodder of field pea/oat mixtures destined for cattle feed

The objective of the study was to establish the effect of component share in mixtures and harvest date on concentrations of selected heavy metals in the green fodder of field pea, oat, and their mixtures. The research hypothesis assumed that the cultivation of peas and oats in pure sowing, and in mixtures will also allow to choose combinations from which the forage will have the lowest content of heavy metals. Field research was conducted at the Zawady Experimental Farm (52° 03' 39″ N, 22° 33' 80″ E) which belongs to Siedlce University of Natural Sciences and Humanities. Two factors were tested in the study: I-component share in the mixture: field pea-pure stand 100%, oat-pure stand 100%, field pea 75% + oat 25%, field pea 50% + oat 50%, field pea 25% + oat 75%; II-harvest date: field pea flowering stage, field pea flat pod stage. Plant material was sampled to determine the following elements: Cu, Zn, Cd, Pb, Cr, and Ni. The results of the study demonstrated that field pea grown in pure stand had the highest copper and zinc contents, and the lowest chromium and nickel contents. Field pea mixed with oat significantly reduced heavy metal content in green fodder. Cadmium and lead contents in the green fodder of field pea/oat mixtures were too low to be determined by means of the spectrometer Perkin Elmer Optima 8300. Regular checks of heavy metal contents are recommended in spite of their low amounts in the green fodder of field pea/oat mixtures.

WRINKLED1 homologs highly and functionally express in oil-rich endosperms of oat and castor

Oat (Avena sativa) and castor (Ricinus communis) accumulate a large amount of lipids in their endosperms, however the molecular mechanism remains unknown. In this study, differences in oil regulators between oat and wheat (Triticum aestivum) as well as common features between oat and castor were tested by analyzing their transcriptomes with further q-PCR analysis. Results indicated that WRINKLED1 (WRI1) homologs and their target genes highly expressed in the endosperms of oat and castor, but not in the starchy endosperms of wheat. Expression pattern of WRI1s was in agreement with that of oil accumulation. Three AsWRI1s (AsWRI1a, AsWRI1b and AsWRI1c) and one RcWRI1 were identified in the endosperms of oat and castor, respectively. AsWRI1c lacks VYL motif, which is different from the other three WRI1s. Expressions of these four WRI1s all complemented the phenotypes of Arabidopsis wri1-1 mutant. Overexpression of these WRI1s in Arabidopsis and tobacco BY2 cells increased oil contents of seeds and total fatty acids of the cells, respectively. Moreover, this overexpression also resulted in up-regulations of WRI1 target genes, such as PKp-β1. Taken together, our results suggest that high and functional expression of WRI1 play a key role in the oil-rich endosperms and the VYL motif is dispensable for WRI1 function.