Dynamics of soil arthropod communities in the annual cultivated Gramineae grasslands in alpine region, Northwest Sichuan.

The dynamics of soil arthropod communities in annual monoculture grasslands is still unclear, which restricts the understanding of the degradation mechanism of cultivated grasslands. We cultivated two annual gramineae species, Lolium multiflorum and Avena sativa, separately in Hongyuan County, located on the eastern edge of the Qinghai-Tibet Plateau, in April 2019. We investigated soil arthropods, plant communities and soil properties in the cultivated grasslands and natural grassland in the late September every year from 2019 to 2022. The results showed that: 1) The taxonomic composition of soil arthropod communities differed significantly among three grasslands and sampling years. 2) There was no significant difference in the density, taxonomic richness, Shannon index and evenness index of soil arthropod communities among three grasslands. 3) The density of soil arthropod communities significantly fluctuated across years in three grasslands, and the taxonomic richness and Shannon index decreased significantly in the L. multiflorum and A. sativa grasslands, with the evenness index declining significantly only in the fourth year. The Shannon index fluctuated significantly and the evenness index varied little in natural grassland. 4) The above- and below-ground biomass, the contents of soil total P, total K and available N were the main factors influencing the taxonomic composition, density and diversity indices of soil arthropod communities. The results suggested that the cultivation of annual gramineae grasslands have significant effects on taxonomic composition, but not on density and diversity of soil arthropod communities, and those variables change significantly across different years.

Photosynthetic performance of glumes of oat spikelets is more stable for grain-filling stage under drought stress.

Drought stress affects plant photosynthesis, leading to a reduction in the quality and yield of crop production. Non-foliar organs play a complementary role in photosynthesis during plant growth and development and are important sources of energy. However, there are limited studies on the performance of non-foliar organs under drought stress. The photosynthetic-responsive differences of oat spikelet organs (glumes, lemmas and paleas) and flag leaves to drought stress during the grain-filling stage were examined. Under drought stress, photosynthetic performance of glume is more stable. Intercellular CO2 concentration (Ci), chlorophyll b, maximum photochemical efficiency of photosystem II. (Fv/Fm), and electron transport rate (ETR) were significantly higher in the glume compared to the flag leaf. The transcriptome data revealed that stable expression of the RCCR gene under drought stress was the main reason for maintaining higher chlorophyll content in the glume. Additionally, no differential expression genes (DEGs) related to Photosystem Ⅰ (PSI) reaction centers were found, and drought stress primarily affects the Photosystem II (PSII) reaction center. In spikelets, the CP43 and CP47 subunits of PSII and the AtpB subunit of ATP synthase were increased on the thylakoid membrane, contributing to photosynthetic stabilisation of spikelets as a means of supplementing the limited photosynthesis of the leaves under drought stress. The results enhanced understanding of the photosynthetic performance of oat spikelet during the grain-filling stage, and also provided an important basis on improving the photosynthetic capacity of non-foliar organs for the selection and breeding new oat varieties with high yield and better drought resistance.

Deficit irrigation of reclaimed water relieves oat drought stress while controlling the risk of PAEs pollution in microplastics-polluted soil.

Reclaimed water irrigation has emerged as a critical alternative in agricultural regions facing water scarcity. However, soil pollution with microplastics (MPs) greatly increases the exposure risk and toxic effects of reclaimed water contaminations, such as phthalate esters (PAEs). A field experiment consisting of soil column pots evaluated the feasibility of using PAEs-contaminated water to irrigate oats (Avena sativa L.) in drought seasons. Three irrigation regimens based on soil matric potential thresholds (-10 kPa, -30 kPa, -50 kPa) explored the impact of PAE-contaminated water on oat physiology and environmental pollution in soil with and without MPs contamination. The results showed that treating oats at the SMP of -30 kPa boosted shoot biomass by 3.1%-14.0% compared to the drought condition at -50 kPa, and the root biomass of oats was significantly increased. The physiological metrics of oats indicated that irrigation at -50 kPa induced drought stress and oxidative damage in oats, particularly during the milk stage. Different irrigation treatments influenced the accumulation of PAEs in plants, soil, and leachate. The ratios of leachate to irrigation water in -10 kPa treatment with and without MPs addition were 1.18% and 4.48%, respectively, which aggravated the accumulation of pollutants in deep soil layers and may cause groundwater pollution. MPs pollution in soil increased the content of PAEs in the harvested oats and reduced the transport and accumulation of PAEs in deep soil layers (20-50 cm) and leachate. The coupling of PAEs in irrigation water with soil MPs pollution may exacerbate plant damage. However, the damage can be minimized under the scheduled irrigation at -30 kPa which could balance crop yield and potential risks.

A Bacillus velezensis strain isolated from oats with disease-preventing and growth-promoting properties.

Endophytes have been shown to promote plant growth and health. In the present study, a Bacillus velezensis CH1 (CH1) strain was isolated and identified from high-quality oats, which was capable of producing indole-3-acetic acid (IAA) and strong biofilms, and capabilities in the nitrogen-fixing and iron carriers. CH1 has a 3920 kb chromosome with 47.3% GC content and 3776 code genes. Compared genome analysis showed that the largest proportion of the COG database was metabolism-related (44.79%), and 1135 out of 1508 genes were associated with the function "biosynthesis, transport, and catabolism of secondary metabolites." Furthermore, thirteen gene clusters had been identified in CH1, which were responsible for the synthesis of fifteen secondary metabolites that exhibit antifungal and antibacterial properties. Additionally, the strain harbors genes involved in plant growth promotion, such as seven putative genes for IAA production, spermidine and polyamine synthase genes, along with multiple membrane-associated genes. The enrichment of these functions was strong evidence of the antimicrobial properties of strain CH1, which has the potential to be a biofertilizer for promoting oat growth and disease resistance.

Cytological structures and physiological and biochemical characteristics of covered oat (Avena sativa L.) and naked oat (Avena nuda L.) seeds during high-temperature artificial aging.

BACKGROUND: Seed aging, a natural and inevitable process occurring during storage. Oats, an annual herb belonging to the Gramineae family and pooideae. In addition to being a healthy food, oats serve as ecological pastures, combating soil salinization and desertification. They also play a role in promoting grassland agriculture and supplementing winter livestock feed. However, the high lipid and fat derivatives contents of oat seeds make them susceptible to deterioration, as fat derivatives are prone to rancidity, affecting oat seed production, storage, development, and germplasm resource utilization. Comparative studies on the effects of aging on physiology and cytological structure in covered and naked oat seeds are limited. Thus, our study aimed to determine the mechanism underlying seed deterioration in artificially aged 'LongYan No. 3' (A. sativa) and 'BaiYan No. 2' (A. nuda) seeds, providing a basis for the physiological evaluation of oat seed aging and serving as a reference for scientifically safe storage and efficient utilization of oats. RESULTS: In both oat varieties, superoxide dismutase and catalase activities in seeds showed increasing and decreasing trends, respectively. Variance analysis revealed significant differences and interaction in all measured indicators of oat seeds between the two varieties at different aging times. 'LongYan No. 3' seeds, aged for 24-96 h, exhibited a germination rate of < 30%, Conductivity, malondialdehyde, soluble sugar, and soluble protein levels increased more significantly than the 'BaiYan No. 2'. With prolonged aging leading to cell membrane degradation, reactive oxygen species accumulation, disrupted antioxidant enzyme system, evident embryo cell swelling, and disordered cell arrangement, blocking the nutrient supply route. Simultaneously, severely concentrated chromatin in the nucleus, damaged mitochondrial structure, and impaired energy metabolism were noted, resulting in the loss of 'LongYan No. 3' seed vitality and value. Conversely, 'BaiYan No. 2' seeds showed a germination rate of 73.33% after 96 h of aging, consistently higher antioxidant enzyme activity during aging, normal embryonic cell shape, and existence of the endoplasmic reticulum. CONCLUSIONS: ROS accumulation and antioxidant enzyme system damage in aged oat seeds, nuclear chromatin condensation, mitochondrial structure damage, nucleic acid metabolism and respiration weakened, oat seed vigor decreased. 'LongYan No. 3' seeds were more severely damaged under artificial aging than 'BaiYan No. 2' seeds, highlighting their heightened susceptibility to aging effects.

Variation and interrelationships in the growth, yield, and lodging of oat under different planting densities.

Background: Oat is a dual-purpose cereal used for grain and forage. The demand of oat has been increasing as the understanding of the nutritional, ecological, and economic values of oat increased. However, the frequent lodging during the growing period severely affect the high yielding potential and the quality of the grain and forage of oat. Methods: Therefore, we used the lodging-resistant variety LENA and the lodging-sensitive variety QY2 as materials, implementing four different planting densities: 2.25×106 plants/ha (D1), 4.5×106 plants/ha (D2), 6.75×106 plants/ha (D3), and 9×106 plants/ha (D4). At the appropriate growth and development stages, we assessed agronomic traits, mechanical characteristics, biochemical compositions, yield and its components. The study investigated the impact of planting density on the growth, lodging, and yield of oat, as well as their interrelationships. Additionally, we identified the optimal planting density to establish a robust crop structure. The research aims to contribute to the high-yield and high-quality cultivation of oat. Results: We observed that with increasing planting density, plant height, grass and grain yields of both varieties first increased and then decreased; root fresh weight, stem diameter, stem wall thickness, stem puncture strength, breaking strength, compressive strength, lignin and crude fiber contents, and yield components decreased; whereas the lodging rate and lodging coefficient increased. Planting density affects lodging by regulating plant height, height of center of gravity, stem wall thickness, internode length, and root fresh weight of oat. Additionally, it can impact stem mechanical strength by modulating the synthesis of lignin and crude fiber, which in turn affecting lodging resistance. Plant height, height of center of gravity, stem wall thickness, internode length, root fresh weight, breaking strength, compressive strength, lignin and crude fiber content, single-plant weight, grain yield and 1,000-grain weight can serve as important indicators for evaluating oat stem lodging resistance. We also noted that planting density affected grain yield both directly and indirectly (by affecting lodging); high density increased lodging rate and decreased grain yield, mainly by reducing 1,000-grain weight. Nonetheless, there was no significant relationship between lodging and grass yield. As appropriate planting density can increase the yield while maintaining good lodging resistance, in this study, 4.5×106 plants/ha (D2) was found to be the best planting density for oat in terms of lodging resistance and grass and grain yield. These findings can be used as a reference for oat planting.

Mitigating salt stress by conditioning seeds with ultraviolet light (UV-C) in white oats (Avena sativa L.).

Seed conditioning with ultraviolet light (UV-C) might (1) improve crop yield and quality, (2) reduce the use of agrochemicals during cultivation, and (3) increase plant survival in high salinity environments. The aim of this study was to examine the effects of UV-C conditioning of white oat seeds at two doses (0.85 and 3.42 kJ m-2) under salinity stress (100 mM NaCl). Seeds were sown on germination paper and kept in a germination chamber at 20°C. Germination and seedling growth parameters were evaluated after 5 and 10 days. Data demonstrated that excess salt reduced germination and initial growth of white oat seedlings. In all the variables analyzed, exposure of seeds to UV-C under salt stress exerted a positive effect compared to non-irradiated control. The attenuating influence of UV-C in germination was greater at 0.85 than at 3.42 kJ m-2. Thus, data indicate that conditioning white oat seeds in UV-C light produced greater tolerance to salt stress. These findings suggest that UV-C conditioning of white oat seeds may be considered as a simple and economical strategy to alleviate salt-induced stress.

Differential expression and global analysis of miR156/SQUAMOSA promoter binding-like proteins (SPL) module in oat.

SQUAMOSA promoter binding-like proteins (SPLs) are important transcription factors that influence growth phase transition and reproduction in plants. SPLs are targeted by miR156 but the SPL/miR156 module is completely unknown in oat. We identified 28 oat SPL genes (AsSPLs) distributed across all 21 oat chromosomes except for 4C and 6D. The oat- SPL gene family represented six of eight SPL phylogenetic groups, with no AsSPLs in groups 3 and 7. A novel oat miR156 (AsmiR156) family with 21 precursors divided into 7 groups was characterized. A total of 16 AsSPLs were found to be targeted by AsmiR156. Intriguingly, AsSPL3s showed high transcript abundance during early inflorescence (GS-54), as compared to the lower abundance of AsmiR156, indicating their role in reproductive development. Unravelling the SPL/miR156 regulatory hub and alterations in expression patterns of AsSPLs could provide an essential toolbox for genetic improvement in the cultivated oat.

Genome-Wide Association Study Uncovers Genomic Regions Associated with Coleoptile Length in a Worldwide Collection of Oat.

The length of coleoptile is crucial for determining the sowing depth of oats in low-precipitation regions, which is significant for oat breeding programs. In this study, a diverse panel of 243 oat accessions was used to explore coleoptile length in two independent experiments. The panel exhibited significant variation in coleoptile length, ranging from 4.66 to 8.76 cm. Accessions from Africa, America, and the Mediterranean region displayed longer coleoptile lengths than those from Asia and Europe. Genome-wide association studies (GWASs) using 26,196 SNPs identified 34 SNPs, representing 32 quantitative trait loci (QTLs) significantly associated with coleoptile length. Among these QTLs, six were consistently detected in both experiments, explaining 6.43% to 10.07% of the phenotypic variation. The favorable alleles at these stable loci additively increased coleoptile length, offering insights for pyramid breeding. Gene Ontology (GO) analysis of the 350 candidate genes underlying the six stable QTLs revealed significant enrichment in cell development-related processes. Several phytochrome-related genes, including auxin transporter-like protein 1 and cytochrome P450 proteins, were found within these QTLs. Further validation of these loci will enhance our understanding of coleoptile length regulation. This study provides new insights into the genetic architecture of coleoptile length in oats.

Germination and stress tolerance of oats treated with pulsed electric field at different phases of seedling growth.

This study explores the impact of pulsed electric field (PEF) application on oat seedling growth and stress tolerance. PEF treatment (99 monopolar, rectangular pulses lasting 10 µs each, with a frequency of 13 Hz and a nominal electric field strength of 2250 V/cm) was applied at two growth stages: (i) when the seedlings had 0.2 cm roots emerging from the kernel, and (ii) when they had a 0.4 cm shoot emerging from the kernel. Post-treatment, the seedlings were hydroponically grown for 8 days. To induce stress, the hydroponic medium was augmented with PEG (15 %) to induce drought stress and NaCl (150 mM) to induce salinity stress. Results demonstrate that applying PEF improved the growth of the root and shoot of oat seedlings. This effect was more pronounced when applied to more developed seedlings. When PEF was applied during the later stage of germination, seedlings exposed to salinity stress showed enhanced shoot growth compared to the control. Under the studied conditions, the application of PEF had no impact on the growth of seedlings under drought stress.

The world's first glyphosate-resistant case of Avena fatua L. and Avena sterilis ssp. ludoviciana (Durieu) Gillet & Magne and alternative herbicide options for their control.

Avena fatua and A. ludoviciana (commonly known as wild oats) are the most problematic winter grass species in fallows and winter crops in the northeast region of Australia. A series of experiments were conducted to evaluate the performance of glyphosate and alternative post-emergence herbicides on A. fatua and A. ludoviciana. This study reports the world's first glyphosate-resistant (GR) biotypes of A. fatua and A. ludoviciana. The glyphosate dose required to kill 50% of the plants (LD50) and to reduce 50% of the biomass (GR50) for the GR biotype of A. fatua was 556 g a.e./ha and 351 g a.e./ha, respectively. These values for A. ludoviciana were 848 g a.e./ha and 289 g a.e./ha. Regardless of the growth stage (3-4 or 6-7 leaf stages), clethodim (120 g a.i./ha), haloxyfop (78 g a.i./ha), pinoxaden (20 g a.i./ha), and propaquizafop (30 g a.i./ha) were the best alternative herbicide options for the control of A. fatua and A. ludoviciana. The efficacy of butroxydim (45 g a.i./ha), clodinafop (120 g a.i./ha), imazamox + imazapyr (36 g a.i./ha), and paraquat (600 g a.i./ha) reduced at the advanced growth stage. Glufosinate (750 g a.i./ha), flamprop (225 g a.i./ha), and pyroxsulam + halauxifen (20 g a.i./ha) did not provide effective control of Avena species. This study identified alternative herbicide options to manage GR biotypes of A. fatua and A. ludoviciana.

SPIRE-a software tool for bicontinuous phase recognition: application for plastid cubic membranes.

Bicontinuous membranes in cell organelles epitomize nature's ability to create complex functional nanostructures. Like their synthetic counterparts, these membranes are characterized by continuous membrane sheets draped onto topologically complex saddle-shaped surfaces with a periodic network-like structure. Their structure sizes, (around 50-500 nm), and fluid nature make transmission electron microscopy (TEM) the analysis method of choice to decipher their nanostructural features. Here we present a tool, Surface Projection Image Recognition Environment (SPIRE), to identify bicontinuous structures from TEM sections through interactive identification by comparison to mathematical "nodal surface" models. The prolamellar body (PLB) of plant etioplasts is a bicontinuous membrane structure with a key physiological role in chloroplast biogenesis. However, the determination of its spatial structural features has been held back by the lack of tools enabling the identification and quantitative analysis of symmetric membrane conformations. Using our SPIRE tool, we achieved a robust identification of the bicontinuous diamond surface as the dominant PLB geometry in angiosperm etioplasts in contrast to earlier long-standing assertions in the literature. Our data also provide insights into membrane storage capacities of PLBs with different volume proportions and hint at the limited role of a plastid ribosome localization directly inside the PLB grid for its proper functioning. This represents an important step in understanding their as yet elusive structure-function relationship.

Calcium amendment for improved germination, plant growth, and leaf photosynthetic electron transport in oat (Avena sativa) under NaCl stress.

Calcium (Ca2+) is an essential nutrient element for plants as it stabilizes the membrane system structure and controls enzyme activity. To investigate the effects of Ca2+ on plant growth and leaf photosynthetic electron transport in oat (Avena sativa) under NaCl stress, oat seeds and plants were cultivated in nutrient solutions with single NaCl treatment and NaCl treatment with CaCl2 amendment. By measuring the seed germination rate, plant growth, Na+ and Cl- accumulation in leaves, ion leakage in seedlings and leaves, prompt chlorophyll a fluorescence (PF) transient (OJIP), delayed chlorophyll a fluorescence (DF), and modulated 820 nm reflection (MR) values of the leaves at different growth phases, we observed that Ca2+ alleviated the inhibition of germination and plant growth and decreased Na+ and Cl- accumulation and ion leakage in the leaves under NaCl stress. NaCl stress changed the curves of the OJIP transient, induced PF intensity at P-step (FP) decrease and PF intensity at J-step (FJ) increase, resulted in obvious K and L bands, and altered the performance index of absorption (PIABS), the absorption of antenna chlorophyll (ABS/RC), electron movement efficiency (ETo/TRo), and potential maximum photosynthetic capacity (FV/FM) values. With the time extension of NaCl stress, I1 and I2 in the DF curve showed a decreasing trend, the lowest values of MR/MRO curve increased, and the highest points of the MR/MRO curve decreased. Compared with NaCl treatment, the extent of change induced by NaCl in the values of OJIP, DF and MR was reduced in the NaCl treatment with CaCl2 amendment. These results revealed that Ca2+ might improve the photosynthetic efficiency and the growth of salt-stressed plants by maintaining the integrity of oxygen-evolving complexes and electron transporters on the side of the PSI receptor and enhancing the relationship between the functional units of the photosynthetic electron transport chain. The findings from this study could be used for improving crop productivity in saline alkali lands.

Oat (Avena sativa L.) Anther Culture.

Production of doubled haploids (DHs) by androgenesis is a promising and convenient alternative to traditionally used breeding techniques. Low response of anther culture and strong genotype dependency in the development of embryo-like structures (ELS) was reported for oat (Avena sativa L.). Total homozygosity has been reached in one generation. This chapter describes a step-by-step protocol that can be useful for androgenesis studies and oat DH line production through anther culture.

Oat Doubled Haploid Production Through Wide Hybridization with Maize.

Wide hybridization is one of the haploid-inducing techniques that can accelerate the breeding process. Obtaining new cultivars is crucial to solve the problem of the constantly growing world population and global increase in demand for food, feed and renewable energy under changing environmental conditions. Here, we present a detailed protocol for obtaining oat (Avena sativa L.) doubled haploids (DHs) by pollination with maize (Zea mays L.). After fertilization, not only oat homozygotes, but also oat × maize hybrid zygotes can be formed, and during early embryo development, maize chromosomes are preferentially eliminated, which ultimately results in haploid plant formation. This chapter describes a method to produce oat DHs by crossing oat with maize, covering all steps from crossings to haploid plant regeneration and chromosome doubling.

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.

Growth-promoting effects of Bradyrhizobium soybean symbionts in black oats, white oats, and ryegrass.

Although inoculating soybean with rhizobia for biological nitrogen fixation is a common practice in agriculture, rhizobia are also known to associate with grasses. In this study, we evaluate the potential utility of the rhizobial strains SEMIA 587 and 5019 (Bradyrhizobium elkanii), 5079 (Bradyrhizobium japonicum), and 5080 (Bradyrhizobium diazoefficiens), recommended for Brazilian soybean inoculation, in colonizing black oat plants and promoting growth in black and white oats, and ryegrass. Inoculation of white oats with SEMIA 587 increase the seed germination (SG) by 32.09%, whereas the SG of black oats inoculated with SEMIA 587 and 5019 increased by 40.38% and 37.85%, respectively. Similarly, inoculation of ryegrass with all strains increased SG values between 24.63 and 27.59%. In addition, white oats with SEMIA 587 and 5080 had root areas significantly superior to those in other treatments, whereas inoculation with SEMIA 5079 and 5080 resulted in the highest volume of roots. Likewise, SEMIA 5079 and 5080 significantly increased the length, volume, and area of black oats roots, whereas SEMIA 587 increased the volume, area, and dry mass of roots and shoot. Inoculation in ryegrass with SEMIA 587 significantly increased the root volume. Moreover, most strains transformed with gfp and gus were observed to colonize the roots of black oats. Collectively, the findings of this study indicate that rhizobial strains recommended for inoculation of soybean can also be used to promote the growth of the three assessed grass species, and are able to colonize the roots of black oats.

Natural Co-Occurrence of Multiple Mycotoxins in Unprocessed Oats Grown in Ireland with Various Production Systems.

The natural co-occurrence of 42 mycotoxins was investigated in unprocessed oat grains grown in Ireland. The sample set included a total of 208 oat crops harvested during 2015-2016 and produced using conventional, organic, or gluten free farming systems. A range of different toxins was identified, including the major type A (neosolaniol, HT-2 and T-2 toxins, T-2 triol, and T-2-glucoside, co-occurring in 21 samples) and B trichothecenes (deoxynivalenol, nivalenol, and deoxynivalenol-3-glucoside), enniatins (B1, B, and A1, co-occurring in 12 samples), as well as beauvericin, alternariol, mycophenolic acid, and sterigmatocystin. The influences of sowing season, year, and production system were investigated, eventually indicating that the latter factor may have a higher impact than others on the production of certain mycotoxins in oats. The most frequently quantified compounds were HT-2 (51%) and T-2 (41%) toxins, with gluten free oats containing significantly lower concentrations of HT-2 compared to conventionally produced oats. Although the prevalence and concentrations of mycotoxin found in oat samples in this study should be substantially reduced by processing. However, as mycotoxin occurrence is clearly influenced by multiple factors, controlled field trials should be carried out to define optimal agronomic practices and mitigate mycotoxin production. Furthermore, this work highlights the need for regularly testing cereal-based foods with multi-residue analytical methods with wider specificities than the traditionally screened and regulated toxins, to generate knowledge on the occurrence of several mycotoxins that are, to date, rarely investigated.

Assessing the impact of nitrogen supplementation in oats across multiple growth locations and years with targeted phenotyping and high-resolution metabolite profiling approaches.

Oats (Avena sativa L.) are a healthy food, being high in dietary fibre (e.g. ß-glucans), antioxidants, minerals, and vitamins. Understanding the effect of variety and crop management on nutritional quality is important. The response of four oat varieties to increased nitrogen levels was investigated across multiple locations and years with respect to yield, grain quality and metabolites (assessed via GC- and LC- MS). A novel high-resolution UHPLC-PDA-MS/MS method was developed, providing improved metabolite enrichment, resolution, and identification. The combined phenotyping approach revealed that, amino acid levels were increased by nitrogen supplementation, as were total protein and nitrogen containing lipid levels, whereas health-beneficial avenanthramides were decreased. Although nitrogen addition significantly increased grain yield and ß-glucan content, supporting increasing the total nitrogen levels recommended within agricultural guidelines, oat varietal choice as well as negative impacts upon health beneficial secondary metabolites and the environmental burdens associated with nitrogen fertilisation, require further consideration.

An integrated framework reinstating the environmental dimension for GWAS and genomic selection in crops.

Identifying mechanisms and pathways involved in gene-environment interplay and phenotypic plasticity is a long-standing challenge. It is highly desirable to establish an integrated framework with an environmental dimension for complex trait dissection and prediction. A critical step is to identify an environmental index that is both biologically relevant and estimable for new environments. With extensive field-observed complex traits, environmental profiles, and genome-wide single nucleotide polymorphisms for three major crops (maize, wheat, and oat), we demonstrated that identifying such an environmental index (i.e., a combination of environmental parameter and growth window) enables genome-wide association studies and genomic selection of complex traits to be conducted with an explicit environmental dimension. Interestingly, genes identified for two reaction-norm parameters (i.e., intercept and slope) derived from flowering time values along the environmental index were less colocalized for a diverse maize panel than for wheat and oat breeding panels, agreeing with the different diversity levels and genetic constitutions of the panels. In addition, we showcased the usefulness of this framework for systematically forecasting the performance of diverse germplasm panels in new environments. This general framework and the companion CERIS-JGRA analytical package should facilitate biologically informed dissection of complex traits, enhanced performance prediction in breeding for future climates, and coordinated efforts to enrich our understanding of mechanisms underlying phenotypic variation.