Genome-wide analysis of MYB transcription factor family and AsMYB1R subfamily contribution to ROS homeostasis regulation in Avena sativa under PEG-induced drought stress.

BACKGROUND: The myeloblastosis (MYB) transcription factor (TF) family is one of the largest and most important TF families in plants, playing an important role in a life cycle and abiotic stress. RESULTS: In this study, 268 Avena sativa MYB (AsMYB) TFs from Avena sativa were identified and named according to their order of location on the chromosomes, respectively. Phylogenetic analysis of the AsMYB and Arabidopsis MYB proteins were performed to determine their homology, the AsMYB1R proteins were classified into 5 subgroups, and the AsMYB2R proteins were classified into 34 subgroups. The conserved domains and gene structure were highly conserved among the subgroups. Eight differentially expressed AsMYB genes were screened in the transcriptome of transcriptional data and validated through RT-qPCR. Three genes in AsMYB2R subgroup, which are related to the shortened growth period, stomatal closure, and nutrient and water transport by PEG-induced drought stress, were investigated in more details. The AsMYB1R subgroup genes LHY and REV 1, together with GST, regulate ROS homeostasis to ensure ROS signal transduction and scavenge excess ROS to avoid oxidative damage. CONCLUSION: The results of this study confirmed that the AsMYB TFs family is involved in the homeostatic regulation of ROS under drought stress. This lays the foundation for further investigating the involvement of the AsMYB TFs family in regulating A. sativa drought response mechanisms.

Genome Variability in Artificial Allopolyploid Hybrids of Avena sativa L. and Avena macrostachya Balansa ex Coss. et Durieu Based on Marker Sequences of Satellite DNA and the ITS1-5.8S rDNA Region.

Artificial hybrids between cultivated Avena species and wild Avena macrostachya that possess genes for resistance to biotic and abiotic stresses can be important for oat breeding. For the first time, a comprehensive study of genomes of artificial fertile hybrids Avena sativa × Avena macrostachya and their parental species was carried out based on the chromosome FISH mapping of satellite DNA sequences (satDNAs) and also analysis of intragenomic polymorphism in the 18S-ITS1-5.8S rDNA region, using NGS data. Chromosome distribution patterns of marker satDNAs allowed us to identify all chromosomes in the studied karyotypes, determine their subgenomic affiliation, and detect several chromosome rearrangements. Based on the obtained cytogenomic data, we revealed differences between two A. macrostachya subgenomes and demonstrated that only one of them was inherited in the studied octoploid hybrids. Ribotype analyses showed that the second major ribotype of A. macrostachya was species-specific and was not represented in rDNA pools of the octoploids, which could be related to the allopolyploid origin of this species. Our results indicate that the use of marker satDNAs in cytogenomic studies can provide important data on genomic relationships within Avena allopolyploid species and hybrids, and also expand the potential for interspecific crosses for breeding.

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.

Combined molecular spectroscopic techniques (SR-FTIR, XRF, ATR-FTIR) to study physiochemical and nutrient profiles of Avena sativa grain and nutrition and structure interactive association properties.

Synchrotron radiation based on Fourier transform infrared radiation (SR-FTIR), X-ray fluorescence (XRF) and attenuated total reflection based on Fourier transform infrared radiation (ATR-FTIR) spectroscopy are both fast determining and minimal sample preparing techniques. They are capable of detecting the internal molecular structures. However, these techniques are still not well understood by nutrition researchers for the analysis of feed. The purpose of this review is to introduce advanced SR-FTIR, XRF, and ATR-FTIR molecular techniques, use these techniques to study chemical and nutrient profiles of Avena sativa grain, and lastly to study the nutrition and structure interactive association properties. The review mainly focuses on the following aspects: 1) the background information of Avena sativa grain; its history, chemical composition, nutrient profile, inherent structure, and production; 2) molecular spectroscopic techniques; principles and spectral analysis methodology of SR-FTIR, XRF and ATR-FTIR; 3) the application of SR-FTIR, XRF, and ATR-FTIR as a novel approach. This review provides an insight on how molecular spectroscopic techniques could be used for the study of nutrition and structure interactive association properties.

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.

Utilizing Genomics to Characterize the Common Oat Gene Pool-The Story of More Than a Century of Polish Breeding.

This study was undertaken to investigate the diversity and population structure of 487 oat accessions, including breeding lines from the ongoing programs of the three largest Polish breeding companies, along with modern and historical Polish and foreign cultivars. The analysis was based on 7411 DArTseq-derived SNPs distributed among three sub-genomes (A, C, and D). The heterogeneity of the studied material was very low, as only cultivars and advanced breeding lines were examined. Principal component analysis (PCA), principal coordinate analysis (PCoA), and cluster and STRUCTURE analyses found congruent results, which show that most of the examined cultivars and materials from Polish breeding programs formed major gene pools, that only some accessions derived from Strzelce Plant Breeding, and that foreign cultivars were outside of the main group. During the 120 year oat breeding process, only 67 alleles from the old gene pool were lost and replaced by 67 new alleles. The obtained results indicate that no erosion of genetic diversity was observed within the Polish native oat gene pool. Moreover, current oat breeding programs have introduced 673 new alleles into the gene pool relative to historical cultivars. The analysis also showed that most of the changes in relation to historical cultivars occurred within the A sub-genome with emphasis on chromosome 6A. The targeted changes were the rarest in the C sub-genome. This study showed that Polish oat breeding based mainly on traditional breeding methods-although focused on improving traits typical to this crop, i.e., enhancing the grain yield and quality and improving adaptability-did not significantly narrow the oat gene pool and in fact produced cultivars that are not only competitive in the European market but are also reservoirs of new alleles that were not found in the analyzed foreign materials.

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.

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.

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.

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.

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.

A stress-responsive transcription factor PeNAC1 regulating beta-D-glucan biosynthetic genes enhances salt tolerance in oat.

MAIN CONCLUSION: A Populus euphratica NAC gene regulates (1,3; 1,4)-ß-D-glucan content in oat developing seed and improves the spikelet number and grain number per spike in transgenic oat under salinity conditions Salinity is the major factor affecting the production and quality of oat, and improving oat salt tolerance to increase yield and quality is vital. (1,3;1,4)-ß-D-glucan in Gramineae is the key component in response to various environmental signals, and it is the most important functional ingredient in oat grain. The NAC transcription factors are important candidate genes used in genetic engineering to improve plant abiotic stress tolerance. In this study, we introduced Populus euphratica PeNAC1, controlled by its own promoter, into hexaploid cultivated oat and produced six transgenic lines. Compared to the non-transgenic control, the expression of PeNAC1 significantly improved the seed germination rate, seedling survival rate, and leaf chlorophyll content in the transgenic plants under salt stress. These physiological changes increased the spikelet number and grain number per spike in the transgenic oat under salinity conditions and reduced the yield loss per plant. The results indicated that the heterologous expression of PeNAC1 plays an effective role in improving the salt tolerance in transgenic oat. In addition, overexpressing PeNAC1 significantly increased the (1,3;1,4)-ß-D-glucan content as well as the expression level of the (1,3;1,4)-ß-D-glucan biosynthetic genes AsCslF3, AsCslF6, and AsCslF9 in the transgenic lines under salt stress, which suggested that PeNAC1 regulates the synthesis of (1,3;1,4)-ß-D-glucan. Our research should assist in the discovery of the diverse action modes of NAC proteins, while PeNAC1 will be useful for improving the salt tolerance and quality of oat through molecular breeding.

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

KEY MESSAGE: 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.

Optimization of sowing date and irrigation levels for white oats using the CERES-Barley model.

Studies on the use of deficit irrigation and application of models for estimating agronomic performance of crops can help in more sustainable agricultural managements. The objective of this study was to evaluate the effect of irrigation levels on the agronomic performance of white oat (Avena sativa L.) and accuracy of the CERES-Barley model in simulating white oat growth and yield, as well as performing long-term simulation to identify the best sowing time for each irrigation management. The experiment consisted of five irrigation levels (11%, 31%, 60%, 87%, and 100%), being conducted in two agricultural years in southeastern Brazil. The model was calibrated with data of the treatment without water deficit (100%) of the first year and validated with the data of the other treatments in the 2 years. Long-term analyses, with a historical series of 16 years, were performed to recommend the best sowing dates for each irrigation management. Deficit irrigation linearly reduces the agronomic performance of white oat. The high accuracy of white oat yield estimation (R2 = 0.86; RMSE = 616 kg ha-1) using the CERES-Barley model allowed the long-term simulation for establishing the best sowing date for each irrigation level. For higher irrigation levels, sowing in periods with lower temperature (May and June) is more appropriate, as the 1 °C increment in the average temperature before flowering reduces crop yield by 600 kg ha-1. At irrigation levels with higher deficit, sowing in periods with higher rainfall (March and April) promotes higher crop yield.

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.

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.

Discovery and Chromosomal Location a Highly Effective Oat Crown Rust Resistance Gene Pc50-5.

Crown rust, caused by Puccinia coronata f. sp. avenae, is one of the most destructive fungal diseases of oat worldwide. Growing disease-resistant oat cultivars is the preferred method of preventing the spread of rust and potential epidemics. The object of the study was Pc50-5, a race-specific seedling crown rust resistant gene, highly effective at all growth stages, selected from the differential line Pc50 (Avena sterilis L. CW 486-1 × Pendek). A comparison of crown rust reaction as well as an allelism test showed the distinctiveness of Pc50-5, whereas the proportions of phenotypes in segregating populations derived from a cross with two crown rust-susceptible Polish oat cultivars, Kasztan × Pc50-5 and Bingo × Pc50-5, confirmed monogenic inheritance of the gene, indicating its usefulness in oat breeding programs. Effective gene introgression depends on reliable gene identification in the early stages of plant development; thus, the aim of the study was to develop molecular markers that are tightly linked to Pc50-5. Segregating populations of Kasztan × Pc50-5 were genotyped using DArTseq technology based on next-generation Illumina short-read sequencing. Markers associated with Pc50-5 were located on chromosome 6A of the current version of the oat reference genome (Avena sativa OT3098 v2, PepsiCo) in the region between 434,234,214 and 440,149,046 bp and subsequently converted to PCR-based SCAR (sequence-characterized amplified region) markers. Furthermore, 5426978_SCAR and 24031809_SCAR co-segregated with the Pc50-5 resistance allele and were mapped to the partial linkage group at 0.6 and 4.0 cM, respectively. The co-dominant 58163643_SCAR marker was the best diagnostic and it was located closest to Pc50-5 at 0.1 cM. The newly discovered, very strong monogenic crown rust resistance may be useful for oat improvement. DArTseq sequences converted into specific PCR markers will be a valuable tool for marker-assisted selection in breeding programs.

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.

Two new secondary metabolites isolated from Avena sativa L. (Oat) seedlings and their effects on osteoblast differentiation.

Seedlings of natural crops are valuable sources of pharmacologically active phytochemicals. In this study, we aimed to identify new active secondary metabolites in Avena sativa L. (oat) seedlings. Two new compounds, avenafuranol (1) and diosgenoside (2), along with eight known compounds (3-10) were isolated from the A. sativa L. seedlings. Their chemical structures were elucidated via 1D and 2D NMR spectroscopy, high-resolution ESIMS, IR spectroscopy, optical rotation analysis, and comparisons with the reported literature. The effect of each isolated compound on alkaline phosphatase (ALP) activity for osteoblast differentiation induced by bone morphogenetic protein-2 (BMP-2) was investigated using the C2C12 immortal mouse myoblast cell line. Compounds 1, 4, 6, 8, and 9 induced dose-dependent increases in ALP expression relative to ALP expression in cells treated with only BMP-2, and no cytotoxicity was observed. These results suggest that A. sativa L. seedlings are a natural source of compounds that may be useful for preventing bone disorders.

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.