Influence of nitrogen fertilizer rate and variety on tef [Eragrostis tef (Zucc.) Trotter] nutritional composition and sensory quality of a staple bread (Injera).

In Ethiopia, tef is one of the major staple crops used as a basic raw material for food development such as stable bread called injera. Studies reported that imbalanced N fertilizer reduces the overall deliciousness of grains. Nowadays nitrogenous fertilizers are considered as the source of variation for the quality of injera, Ethiopian traditional flat bread. Therefore, a field experiment was conducted to assess the effects of N fertilizer rates (0, 30, 60, 90, and 120 kg N ha-1) on grain nutrition and sensory quality of injera of three tef varieties of (Kora, Boset, and Asgori). The experiment was conducted in main cropping season in Randomized Complete Block Design with three replications and Di-ammonium Phosphate was used in the same dose. Crop attribute parameters were determined using standard methods. Sensory quality and color of injera were determined by panelists and injera eye software respectively. Results showed that only protein content increased with nitrogen rates, while carbohydrate decreased significantly at (P < 0.05). Kora at the control plot (K0) had better color, flavor, texture, and taste values of injera, but they decreased with nitrogen rates. Injera from white tef varieties had a better acceptance as compared with Asgori red tef variety. Injera eye software indicated that the color of injera was significantly affected by varieties. Kora had a higher (55.74) lightness value followed by Boset (54.71), and Asgori (51.26). Injera from the Asgori variety had a maximum red color. Kora and Boset had higher yellow color on the control plot, but for Asgori it increased with the nitrogen rate.

Barley MLA3 recognizes the host-specificity effector Pwl2 from Magnaporthe oryzae.

Plant nucleotide-binding leucine-rich repeat (NLRs) immune receptors directly or indirectly recognize pathogen-secreted effector molecules to initiate plant defense. Recognition of multiple pathogens by a single NLR is rare and usually occurs via monitoring for changes to host proteins; few characterized NLRs have been shown to recognize multiple effectors. The barley (Hordeum vulgare) NLR gene Mildew locus a (Mla) has undergone functional diversification, and the proteins encoded by different Mla alleles recognize host-adapted isolates of barley powdery mildew (Blumeria graminis f. sp. hordei [Bgh]). Here, we show that Mla3 also confers resistance to the rice blast fungus Magnaporthe oryzae in a dosage-dependent manner. Using a forward genetic screen, we discovered that the recognized effector from M. oryzae is Pathogenicity toward Weeping Lovegrass 2 (Pwl2), a host range determinant factor that prevents M. oryzae from infecting weeping lovegrass (Eragrostis curvula). Mla3 has therefore convergently evolved the capacity to recognize effectors from diverse pathogens.

Comprehensive in silico analysis of the underutilized crop tef (Eragrostis tef (Zucc.) Trotter) genome reveals drought tolerance signatures.

BACKGROUND: Tef (Eragrostis tef) is a C4 plant known for its tiny, nutritious, and gluten-free grains. It contains higher levels of protein, vitamins, and essential minerals like calcium (Ca), iron (Fe), copper (Cu), and zinc (Zn) than common cereals. Tef is cultivated in diverse ecological zones under diverse climatic conditions. Studies have shown that tef has great diversity in withstanding environmental challenges such as drought. Drought is a major abiotic stress severely affecting crop productivity and becoming a bottleneck to global food security. Here, we used in silico-based functional genomic analysis to identify drought-responsive genes in tef and validated their expression using quantitative RT-PCR. RESULTS: We identified about 729 drought-responsive genes so far reported in six crop plants, including rice, wheat, maize, barley, sorghum, pearl millet, and the model plant Arabidopsis, and reported 20 genes having high-level of GO terms related to drought, and significantly enriched in several biological and molecular function categories. These genes were found to play diverse roles, including water and fluid transport, resistance to high salt, cold, and drought stress, abscisic acid (ABA) signaling, de novo DNA methylation, and transcriptional regulation in tef and other crops. Our analysis revealed substantial differences in the conserved domains of some tef genes from well-studied rice orthologs. We further analyzed the expression of sixteen tef orthologs using quantitative RT-PCR in response to PEG-induced osmotic stress. CONCLUSIONS: The findings showed differential regulation of some drought-responsive genes in shoots, roots, or both tissues. Hence, the genes identified in this study may be promising candidates for trait improvement in crops via transgenic or gene-editing technologies.

The Effect of Teff Seed on Hematological Findings and Anthropometric Measurements.

Background: The low incidence of diseases such as celiac, anemia, osteoporosis, and obesity in Ethiopia has aroused interest in the study of teff. The primary objective of this study was to determine the effect of regular consumption of teff seeds on hematological findings and anthropometric measurements in overweight and obese individuals. The secondary objective was to compare these effects of teff seeds with the Mediterranean diet. Methods: In our study, planned as a cohort study, 28 participants followed the teff seed-containing diet (n=14) and the Mediterranean diet (n=14) for 3 months. To determine nutritional status, a 72-h recall was taken. Anthropometric measurements and hematological findings were recorded at the beginning and end of the study. Results: There was a significant decrease in fasting blood glucose, cholesterol, LDL, and HDL levels in the teff group (p<0.05). The increase in total protein levels in the teff group was significantly higher than in the Mediterranean diet group (p=0.05). With increased intake of carbohydrates (g) in the teff group, fasting blood glucose levels decreased significantly. There was no significant difference between the two groups regarding anthropometric measurements. Conclusion: It has been found that the teff seed has no predominance over anthropometric measurements, as compared to the Mediterranean diet, and that it is more effective in improving hematological findings related to obesity. There is a need for more comprehensive studies that also address physical activity, the different types of teff seeds available, and include increased participant numbers.

Isolation and Characterization of Probiotic LAB from Kimchi and Spontaneously Fermented Teff (Eragrostis tef (Zucc.) Trotter) Batter: Their Effects on Phenolic Content of Teff during Fermentation.

Microbial fermentation is proven to induce molecular transformations and produce bioactive compounds thereby enhancing sensory and nutritional quality of flour-based fermented foods. In this study, lactic acid bacteria (LAB) were isolated from Korean kimchi and Ethiopian fermented teff (Eragrostis tef (Zucc.) Trotter) flour batter. Isolates were identified using 16S rRNA gene sequencing and characterized for various probiotic properties. Few trains were selected for further teff flour batter fermentation and evaluating their effects on phenolic contents and compositions. Out of 200 bacterial isolates, 44 of them showed considerable acid and bile tolerance and 22 were tested positive for protease activity. A large number of the isolates showed antimicrobial activities against Salmonella gallinarium indicator strains. Majority of these probiotic strains belonged to Lactobacillus plantarum and Lactobacillus brevis species. All the strains used for fermentation of teff were able to significantly increase total phenolic contents (TPC). An increase in TPC of up to 7-fold was observed in some strains.

A new method for the direct tracking of in vivo lignin nanocapsules in Eragrostis tef (Poaceae) tissues.

Environmental concerns have driven scientists to research new eco-friendly approaches for the preparation of nanosystems. For this purpose, novel bio-polymers have been selected. Among these, one of the most promising is lignin, which is biodegradable and biocompatible. Additionally, lignin is one of the main by-products of the paper industry and can be re-used in nanosystems building. Lignin-based nanosystems could be used in agriculture, to improve the uptake of bioactive compounds, thus avoiding soil pollution. However, the mechanism of penetration in the plant and the route of transportation within the internal plant tissues are unknown and need to be clearly elucidated. Here we present a method of lignin nanocapsules staining and tracking by fluorochrome: Fluoral Yellow 088, which is a well-suited dye for the tracking of lipids and other oil phases. Two different applications were applied: in the first one fourteen-day plants were soaked with fluorescent nanocapsules (fNCs) pure solution and in the second one, Eragrostis tef plants were laid down on blotting paper and soaked with diluted fNCs solution. Wetting the roots of Teff plantlets with the pure fNCs solution resulted in the most efficient way of nanocapsule entrance. The dyeing of lignin nanocapsules allowed us to track them in Eragrostis tef plant tissues through microscopic observations. In particular, fNCs were proven to be able to permeate roots, reaching xylem vessels where, through water pressure, they reached the leaf.

Characterization and discovery of miRNA and miRNA targets from apomictic and sexual genotypes of Eragrostis curvula.

BACKGROUND: Weeping lovegrass (Eragrostis curvula [Shrad.] Nees) is a perennial grass found in semi-arid regions that is well adapted for growth in sandy soils and drought conditions. E. curvula constitutes a polymorphic complex that includes cytotypes with different ploidy levels (from 2x to 8x), where most polyploids are facultative apomicts, although both sexual reproduction and full apomixis have been reported in this species. Apomixis is thought to be associated with silencing of the sexual pathway, which would involve epigenetic mechanisms. However, a correlation between small RNAs and apomixis has not yet been conclusively established. RESULTS: Aiming to contribute to the elucidation of their role in the expression of apomixis, we constructed small RNA libraries from sexual and apomictic E. curvula genotypes via Illumina technology, characterized the small RNA populations, and conducted differential expression analysis by comparing these small RNAs with the E. curvula reference transcriptome. We found that the expression of two genes is repressed in the sexual genotype, which is associated with specific microRNA expression. CONCLUSION: Our results support the hypothesis that in E. curvula the expression of apomixis leads to sexual repression.

A chemical genetic screen reveals that iminosugar inhibitors of plant glucosylceramide synthase inhibit root growth in Arabidopsis and cereals.

Iminosugars are carbohydrate mimics that are useful as molecular probes to dissect metabolism in plants. To analyse the effects of iminosugar derivatives on germination and seedling growth, we screened a library of 390 N-substituted iminosugar analogues against Arabidopsis and the small cereal Eragrostis tef (Tef). The most potent compound identified in both systems, N-5-(adamantane-1-yl-ethoxy)pentyl- L-ido-deoxynojirimycin (L-ido-AEP-DNJ), inhibited root growth in agar plate assays by 92% and 96% in Arabidopsis and Tef respectively, at 10 µM concentration. Phenocopying the effect of L-ido-AEP-DNJ with the commercial inhibitor (PDMP) implicated glucosylceramide synthase as the target responsible for root growth inhibition. L-ido-AEP-DNJ was twenty-fold more potent than PDMP. Liquid chromatography-mass spectrometry (LC-MS) analysis of ceramide:glucosylceramide ratios in inhibitor-treated Arabidopsis seedlings showed a decrease in the relative quantity of the latter, confirming that glucosylceramide synthesis is perturbed in inhibitor-treated plants. Bioinformatic analysis of glucosylceramide synthase indicates gene conservation across higher plants. Previous T-DNA insertional inactivation of glucosylceramide synthase in Arabidopsis caused seedling lethality, indicating a role in growth and development. The compounds identified herein represent chemical alternatives that can overcome issues caused by genetic intervention. These inhibitors offer the potential to dissect the roles of glucosylceramides in polyploid crop species.

Stomatal and non-stomatal limitations in savanna trees and C4 grasses grown at low, ambient and high atmospheric CO2.

By the end of the century, atmospheric CO2 concentration ([CO2]a) could reach 800 ppm, having risen from ∼200 ppm ∼24 Myr ago. Carbon dioxide enters plant leaves through stomata that limit CO2 diffusion and assimilation, imposing stomatal limitation (LS). Other factors limiting assimilation are collectively called non-stomatal limitations (LNS). C4 photosynthesis concentrates CO2 around Rubisco, typically reducing LS. C4-dominated savanna grasslands expanded under low [CO2]a and are metastable ecosystems where the response of trees and C4 grasses to rising [CO2]a will determine shifting vegetation patterns. How LS and LNS differ between savanna trees and C4 grasses under different [CO2]a will govern the responses of CO2 fixation and plant cover to [CO2]a - but quantitative comparisons are lacking. We measured assimilation, within soil wetting-drying cycles, of three C3 trees and three C4 grasses grown at 200, 400 or 800 ppm [CO2]a. Using assimilation-response curves, we resolved LS and LNS and show that rising [CO2]a alleviated LS, particularly for the C3 trees, but LNS was unaffected and remained substantially higher for the grasses across all [CO2]a treatments. Because LNS incurs higher metabolic costs and recovery compared with LS, our findings indicate that C4 grasses will be comparatively disadvantaged as [CO2]a rises.

Improved glucose metabolism by Eragrostis tef potentially through beige adipocyte formation and attenuating adipose tissue inflammation.

BACKGROUND: Teff is a staple food in Ethiopia that is rich in dietary fiber. Although gaining popularity in Western countries because it is gluten-free, the effects of teff on glucose metabolism remain unknown. AIM: To evaluate the effects of teff on body weight and glucose metabolism compared with an isocaloric diet containing wheat. RESULTS: Mice fed teff weighed approximately 13% less than mice fed wheat (p < 0.05). The teff-based diet improved glucose tolerance compared with the wheat group with normal chow but not with a high-fat diet. Reduced adipose inflammation characterized by lower expression of TNFα, Mcp1, and CD11c, together with higher levels of cecal short chain fatty acids such as acetate, compared with the control diet containing wheat after 14 weeks of dietary treatment. In addition, beige adipocyte formation, characterized by increased expression of Ucp-1 (~7-fold) and Cidea (~3-fold), was observed in the teff groups compared with the wheat group. Moreover, a body-weight matched experiment revealed that teff improved glucose tolerance in a manner independent of body weight reduction after 6 weeks of dietary treatment. Enhanced beige adipocyte formation without improved adipose inflammation in a body-weight matched experiment suggests that the improved glucose metabolism was a consequence of beige adipocyte formation, but not solely through adipose inflammation. However, these differences between teff- and wheat-containing diets were not observed in the high-fat diet group. CONCLUSIONS: Teff improved glucose tolerance likely by promoting beige adipocyte formation and improved adipose inflammation.

Structural profile of soluble and bound phenolic compounds in teff (Eragrostis tef) reveals abundance of distinctly different flavones in white and brown varieties.

Reliable data on polyphenol in teff, an increasingly important food crop, is currently lacking. This study investigated the structural and quantitative profile of soluble and bound polyphenols in white and brown teff grown in Ethiopia and USA using LC-tandem quadrupole mass spectrometry. Thirty-four phenolic compounds (32 newly identified in teff), mostly flavones and phenolic acid derivatives, were characterized. Unusually high levels of flavones were present in both white (1398-2049 µg/g), and brown (1720-1847 µg/g) teff soluble fractions. Interestingly, white teff exclusively contained apigenin derivatives, whereas brown teff contained mainly luteolin derivatives, mostly di-C-linked-glycosides. Additionally, non-extractable procyanidins (condensed tannins) were detected in brown teff only. Phenolic acids (600-728 µg/g) were mostly present in bound fractions, dominated by ferulic acid. Polyphenol profiles of Ethiopian and USA grown grains were similar. The high levels of the relatively rare flavones in teff may have important implications in chronic disease prevention.

Productivity of lactating dairy cows fed diets with teff hay as the sole forage.

Groundwater depletion is one of the most pressing issues facing the dairy industry in arid regions. One strategy to improve the industry's drought resilience involves feeding drought-tolerant forage crops in place of traditional forage crops such as alfalfa and corn silage. The objective of this study was to assess the productivity of lactating dairy cows fed diets with teff hay (Eragrostis tef) as the sole forage. Teff is a warm-season annual grass native to Ethiopia that is well adapted to drought conditions. Nine multiparous Holstein cows (185 ± 31 d in milk; mean ± standard deviation) were randomly assigned to 1 of 3 diets in a 3 × 3 Latin square design with 18-d periods (14 d acclimation and 4 d sampling). Diets were either control, where dietary forage consisted of a combination of corn silage, alfalfa hay, and native grass hay, or 1 of 2 teff diets (teff-A and teff-B), where teff hay [13.97 ± 0.32% crude protein, dry matter (DM) basis] was the sole forage. All 3 diets were formulated for similar DM, crude protein, and nonfiber carbohydrate concentrations. Control and teff-A were matched for concentrations of neutral detergent fiber (NDF) from forage (18.2 ± 0.15% of DM), and teff-B included slightly less, providing 16.6% NDF from forage. Dry matter intake, milk and component production, body weight, body condition score, as well as DM and NDF digestibility were monitored and assessed using mixed model analysis, with significance declared at P < 0.05. Treatment had no effect on dry matter intake (28.1 ± 0.75 kg/d). Similarly, treatment had no effect on milk production (40.7 ± 1.8 kg/d). Concentrations of milk fat (3.90 ± 0.16%) and lactose (4.68 ± 0.07%) were also unaffected by treatment. Teff-A and teff-B increased milk protein concentration compared with the control (3.07 vs. 3.16 ± 0.09%). Treatment had no effect on energy-corrected milk yield (43.4 ± 1.3 kg/d), body weight, or body condition score change. Additionally, treatment had no effect on total-tract DM or NDF digestibility. Results from this study indicate that teff hay has potential to replace alfalfa and corn silage in the diets of lactating dairy cattle without loss of productivity.

Extrinsic iron from soil contributes to Hb regeneration of anaemic rats: implications for foods contaminated with soil iron.

Contamination of foods with extrinsic (soil) Fe is common in developing countries. However, the bioavailability of this extrinsic Fe and the extent to which it contributes to Fe nutrition remains unknown. The present study compared the bioavailability of laboratory- and field-threshed teff (Eragrostisis tef (Zucc) Trotter) to evaluate the bioavailablity of extrinsic soil Fe that resulted from the traditional threshing of the staple grain. Using sequential extraction, Fe was fractionated and its solubility was evaluated. The contribution of the additional extrinsic (soil) Fe to the Hb regeneration of Fe-depleted rats was evaluated using a rat Hb depletion-repletion assay. Weanling male Wistar rats (n 24) were fed Fe-deficient diet for 21 d, and were then repleted for 14 d with diets: either laboratory-threshed teff (35 mg Fe/kg; n 8), field-threshed teff (35 mg intrinsic Fe/kg+ 120 mg soil Fe/kg; n 8), or FeSO4 (control; n 8). Fe content of field-threshed teff (29·4 mg/100 g) was four times greater than that of the laboratory-threshed (6·7 mg/100 g) teff (P<0·05). Soil contamination significantly increased the exchangeable, acid-soluble and reducible fractions obtained after sequential extraction. The relative biological value of the field-threshed teff (88 %) was higher than that of the laboratory-threshed (68 %) teff (P<0·05). Soil Fe can contribute to Hb regeneration in Fe-deficient rats. Considering that contamination of foods with soil is common in Ethiopia and other developing countries, it needs to be accounted for in the design and implementation of fortification programmes to prevent excessive intakes. Human studies are needed to confirm the present findings.

Traditional fermentation of tef injera: Impact on in vitro iron and zinc dialysability.

Tef [Eragrostis tef (Zucc.) Trotter], an ancient cereal mainly produced in Ethiopia, is increasingly getting higher acceptance in the global market because it is gluten free and has high iron content. The aim of this study was to evaluate the in vitro dialysability of Fe and Zn in a backslop fermented gluten free flat bread known as injera. The traditional fermentation caused up to 49-66% reduction of phytic acid (PA). Molar ratios of PA:Fe and PA:Zn decreased from 14 to 1 and from 63 to 19, respectively, after 120h of fermentation. The total soluble fractions of Fe and Zn ranged between 11 and 38% and between 11 and 29%, respectively, after 120h of fermentation. The dialyzable Fe content of the white varieties ranged between 3 and 9% after 120h fermentation while no effect was observed for the brown varieties. The dialyzable Zn ranged between 2 and 11%, with only a clear effect of fermentation in one white variety. Consumption of tef could be a good source of Fe and Zn, but may not provide the absolute recommended daily Fe and Zn intakes.

Biomethane production and physicochemical characterization of anaerobically digested teff (Eragrostis tef) straw pretreated by sodium hydroxide.

The biogas production potential and biomethane content of teff straw through pretreatment by NaOH was investigated. Different NaOH concentrations (1%, 2%, 4% and 6%) were used for each four solid loadings (50, 65, 80 and 95 g/L). The effects of NaOH as pretreatment factor on the biodegradability of teff straw, changes in main compositions and enhancement of anaerobic digestion were analyzed. The result showed that, using 4% NaOH for pretreatment in 80 g/L solid loading produced 40.0% higher total biogas production and 48.1% higher biomethane content than the untreated sample of teff straw. Investigation of changes in chemical compositions and physical microstructure indicated that there was 4.3-22.1% total lignocellulosic compositions removal after three days pretreatment with NaOH. The results further revealed that NaOH pretreatment changed the structural compositions and lignin network, and improved biogas production from teff straw.

Semi-dwarfism and lodging tolerance in tef (Eragrostis tef) is linked to a mutation in the α-Tubulin 1 gene.

Genetic improvement of native crops is a new and promising strategy to combat hunger in the developing world. Tef is the major staple food crop for approximately 50 million people in Ethiopia. As an indigenous cereal, it is well adapted to diverse climatic and soil conditions; however, its productivity is extremely low mainly due to susceptibility to lodging. Tef has a tall and weak stem, liable to lodge (or fall over), which is aggravated by wind, rain, or application of nitrogen fertilizer. To circumvent this problem, the first semi-dwarf lodging-tolerant tef line, called kegne, was developed from an ethyl methanesulphonate (EMS)-mutagenized population. The response of kegne to microtubule-depolymerizing and -stabilizing drugs, as well as subsequent gene sequencing and segregation analysis, suggests that a defect in the α-Tubulin gene is functionally and genetically tightly linked to the kegne phenotype. In diploid species such as rice, homozygous mutations in α-Tubulin genes result in extreme dwarfism and weak stems. In the allotetraploid tef, only one homeologue is mutated, and the presence of the second intact α-Tubulin gene copy confers the agriculturally beneficial semi-dwarf and lodging-tolerant phenotype. Introgression of kegne into locally adapted and popular tef cultivars in Ethiopia will increase the lodging tolerance in the tef germplasm and, as a result, will improve the productivity of this valuable crop.

Phytic acid degrading lactic acid bacteria in tef-injera fermentation.

Ethiopian injera, a soft pancake, baked from fermented batter, is preferentially prepared from tef (Eragrostis tef) flour. The phytic acid (PA) content of tef is high and is only partly degraded during the fermentation step. PA chelates with iron and zinc in the human digestive tract and strongly inhibits their absorption. With the aim to formulate a starter culture that would substantially degrade PA during injera preparation, we assessed the potential of microorganisms isolated from Ethiopian household-tef fermentations to degrade PA. Lactic acid bacteria (LAB) were found to be among the dominating microorganisms. Seventy-six isolates from thirteen different tef fermentations were analyzed for phytase activity and thirteen different isolates of seven different species were detected to be positive in a phytase screening assay. In 20-mL model tef fermentations, out of these thirteen isolates, the use of Lactobacillus (L.) buchneri strain MF58 and Pediococcus pentosaceus strain MF35 resulted in lowest PA contents in the fermented tef of 41% and 42%, respectively of its initial content. In comparison 59% of PA remained when spontaneously fermented. Full scale tef fermentation (0.6L) and injera production using L. buchneri MF58 as culture additive decreased PA in cooked injera from 1.05 to 0.34±0.02 g/100 g, representing a degradation of 68% compared to 42% in injera from non-inoculated traditional fermentation. The visual appearance of the pancakes was similar. The final molar ratios of PA to iron of 4 and to zinc of 12 achieved with L. buchneri MF58 were decreased by ca. 50% compared to the traditional fermentation. In conclusion, selected LAB strains in tef fermentations can degrade PA, with L. buchneri MF58 displaying the highest PA degrading potential. The 68% PA degradation achieved by the application of L. buchneri MF58 would be expected to improve human zinc absorption from tef-injera, but further PA degradation is probably necessary if iron absorption has to be increased.

Influence of sourdough on in vitro starch digestibility and predicted glycemic indices of gluten-free breads.

Gluten-free flours (buckwheat, quinoa, sorghum and teff) were fermented using obligate heterofermentative strain Weissella cibaria MG1 (Wc) and facultative heterofermentative Lactobacillus plantarum FST1.7 (Lp). Starch hydrolysis of breads with and without sourdough (controls) was analyzed in vitro using enzymatic digestion followed by dialysis (10-11 kDa). Hydrolysis indices as well as predicted glycemic indices (pGI) were calculated from reducing sugars released into the dialysate. Amounts of resistant starch (RS; % of total starch) were determined by enzymatic digestion. Upon sourdough addition, RS significantly decreased in buckwheat (Wc 1.28%, Lp 1.44%) and teff sourdough breads (Wc 0.87%, Lp 0.98%) in comparison to their controls (2.01% and 1.92%, respectively). However, no correlation was found with starch hydrolysis. Predicted GIs were reduced upon sourdough addition in wheat (ctrl 100; Wc 85; Lp 76) in comparison to control breads. This was not the case in most gluten-free breads with the exception of sorghum (ctrl 72; Lp 69) and teff sourdough breads (ctrl 74; Lp 68). In contrast, increased pGIs were found in quinoa (ctrl 95; Wc 106; Lp 103) and buckwheat sourdough breads (ctrl 80; Wc 89; Lp 86).

Influence of dextran-producing Weissella cibaria on baking properties and sensory profile of gluten-free and wheat breads.

Breads based on gluten-free buckwheat, quinoa, sorghum and teff flours were produced with addition of 20% sourdough fermented with exopolysaccharide (EPS) producing Weissella cibaria MG1. Wheat bread was baked as a reference. Dough rheology, bread quality parameters and sensory properties of the sourdough-containing breads were compared to sourdough non-containing control breads of the respective flour. The specific volume remained unaffected by sourdough application. In buckwheat, sorghum, teff and wheat sourdough breads acidification increased crumb porosity compared to control breads. Crumb hardness was significantly reduced in buckwheat (-122%), teff (-29%), quinoa (-21%) and wheat sourdough breads (-122%). The staling rate was significantly reduced in buckwheat, teff and wheat sourdough breads. Water activity of the sourdough containing bread crumb was not influenced by the presence of EPS. Due to the presence of exopolysaccharides (EPS) and influence of acidification, the dough strength, AF, as measured by oscillation tests decreased significantly in sourdough-containing buckwheat, sorghum and wheat dough, but increased in sourdough-containing quinoa and teff dough. Microbial shelf-life was significantly prolonged neither for gluten-free sourdough nor for wheat sourdough breads. Scanning electron microscopy of control and sourdough bread crumbs did not show differences concerning structural starch features. In addition, the aroma of most bread was not improved by sourdough addition.

Plastic traits of an exotic grass contribute to its abundance but are not always favourable.

In herbaceous ecosystems worldwide, biodiversity has been negatively impacted by changed grazing regimes and nutrient enrichment. Altered disturbance regimes are thought to favour invasive species that have a high phenotypic plasticity, although most studies measure plasticity under controlled conditions in the greenhouse and then assume plasticity is an advantage in the field. Here, we compare trait plasticity between three co-occurring, C(4) perennial grass species, an invader Eragrostis curvula, and natives Eragrostis sororia and Aristida personata to grazing and fertilizer in a three-year field trial. We measured abundances and several leaf traits known to correlate with strategies used by plants to fix carbon and acquire resources, i.e. specific leaf area (SLA), leaf dry matter content (LDMC), leaf nutrient concentrations (N, C:N, P), assimilation rates (Amax) and photosynthetic nitrogen use efficiency (PNUE). In the control treatment (grazed only), trait values for SLA, leaf C:N ratios, Amax and PNUE differed significantly between the three grass species. When trait values were compared across treatments, E. curvula showed higher trait plasticity than the native grasses, and this correlated with an increase in abundance across all but the grazed/fertilized treatment. The native grasses showed little trait plasticity in response to the treatments. Aristida personata decreased significantly in the treatments where E. curvula increased, and E. sororia abundance increased possibly due to increased rainfall and not in response to treatments or invader abundance. Overall, we found that plasticity did not favour an increase in abundance of E. curvula under the grazed/fertilized treatment likely because leaf nutrient contents increased and subsequently its' palatability to consumers. E. curvula also displayed a higher resource use efficiency than the native grasses. These findings suggest resource conditions and disturbance regimes can be manipulated to disadvantage the success of even plastic exotic species.