True Ileal Amino Acid Digestibility and Protein Quality of 15N-Labeled Faba Bean in Healthy Humans

BACKGROUND

The recommended transition toward more plant-based diets, particularly containing legumes, requires a wider knowledge of plant protein bioavailability. Faba beans are cultivated at different latitudes and are used increasingly in human nutrition.

OBJECTIVES

We aimed to assess the nutritional quality of faba bean protein in healthy volunteers equipped with an intestinal tube to implement the ileal 15N balance method.

METHODS

Nine volunteers completed the study (7 males, 2 females, aged 33 ± 10 y, BMI: 24.7 ± 2.6 kg/m2). They were equipped with a nasoileal tube. After fasting overnight, they ingested a test meal consisting of cooked mash of dehulled faba bean seeds (20 g protein per serving of approximately 250 g) intrinsically labeled with 15N. Samples of ileal contents, plasma, and urine were collected over an 8-h postprandial period. Undigested nitrogen (N) and amino acids (AAs) were determined using isotopic MS, and subsequently, ileal digestibility and digestible indispensable amino acid score (DIAAS) were calculated. The measurement of postprandial deamination allowed calculation of the net postprandial protein utilization (NPPU).

RESULTS

The ileal N digestibility was 84.1% ± 7.7%. Postprandial deamination represented 19.2% ± 3.6% of ingested N, and the NPPU was 64.7% ± 9.7%. The ileal digestibility of individual AAs varied from 85.1% ± 13.7% for histidine to 94.2% ± 3.6% for glutamine + glutamate. The mean AA digestibility was ∼6 percentage points higher than the digestibility of N, reaching 89.8% ± 5.9%, whereas indispensable AA digestibility was 88.0% ± 7.3%. Histidine and tryptophan were the first limiting AAs [DIAAS = 0.77 (calculated by legume-specific N-to-protein conversion factor 5.4); 0.67 (by default factor 6.25)]. Sulfur AAs were limiting to a lesser extent [DIAA ratio = 0.94 (N × 5.4); 0.81 (N × 6.25)].

CONCLUSIONS

Protein ileal digestibility of cooked, dehulled faba beans in humans was moderate (<85%), but that of AAs was close to 90%. Overall protein quality was restricted by the limited histidine and tryptophan content. This trial was registered at clinicaltrials.gov as NCT05047757.

Antioxidant and Angiotensin-Converting Enzyme Inhibitory Activity of Faba Bean-Derived Peptides After In Vitro Gastrointestinal Digestion: Insight into Their Mechanism of Action

Faba bean flour, after in vitro gastrointestinal digestion, showed important antioxidant and angiotensin-converting enzyme (ACE) inhibitory activities. In the present study, 11 faba bean- derived peptides were synthesized to confirm their bioactivities and provide a deeper understanding of their mechanisms of action. The results revealed that 7 peptides were potent antioxidants, namely, NYDEGSEPR, TETWNPNHPEL, TETWNPNHPE, VIPTEPPH, VIPTEPPHA, VVIPTEPPHA, and VVIPTEPPH. Among them, TETWNPNHPEL had the highest activity in the ABTS (EC50 = 0.5 ± 0.2 mM) and DPPH (EC50 = 2.1 ± 0.1 mM) assays (p < 0.05), whereas TETWNPNHPE had the highest activity (p < 0.05) in the ORAC assay (2.84 ± 0.08 mM Trolox equivalent/mM). Synergistic and/or additive effects were found when selected peptides (TETWNPNHPEL, NYDEGSEPR, and VVIPTEPPHA) were combined. Four peptides were potent ACE inhibitors, where VVIPTEPPH (IC50 = 43 ± 1 μM) and VVIPTEPPHA (IC50 = 50 ± 5 μM) had the highest activity (p < 0.05), followed by VIPTEPPH (IC50 = 90 ± 10 μM) and then VIPTEPPHA (IC50 = 123 ± 5 μM) (p < 0.05). These peptides were noncompetitive inhibitors, as supported by kinetic studies and a molecular docking investigation. This study demonstrated that peptides derived from faba beans have multifunctional bioactivities, making them a promising food-functional and nutraceutical ingredient.

Preparation of isolated guard cells, containing cell walls, from Vicia faba

Stomatal movement, initiated by specialized epidermal cells known as guard cells (GCs), plays a pivotal role in plant gas exchange and water use efficiency. Despite protocols existing for isolating GCs through proplasting for carrying out biochemical, physiological, and molecular studies, protocals for isolating GCs with their cell walls still intact have been lacking in the literature. In this paper, we introduce a method for the isolation of complete GCs from Vicia faba and show their membrane to remain impermeable through propidium iodide staining. This methodology enables further in-depth analyses into the cell wall composition of GCs, facilitating our understanding of structure-function relationship governing reversible actuation within cells.

Amelioration of NaCl stress on germination, growth, and nitrogen fixation of Vicia faba at isosmotic Na-Ca combinations and Rhizobium

MAIN CONCLUSION

The Na+/Ca2+ ratio of 1/5 ameliorated the inhibitory action of NaCl and improved the germination and growth of Vicia faba. Addition of Rhizobium also enhanced nodulation and nitrogen fixation. Casting light upon the impact of salinity stress on growth and nitrogen fixation of Vicia faba supplemented with Rhizobium has been traced in this work. How Ca2+ antagonizes Na+ toxicity and osmotic stress of NaCl was also targeted in isosmotic combinations of NaCl and CaCl2 having various Na+:Ca2+ ratios. Growth of Vicia faba (cultivar Giza 3) was studied at two stages: germination and seedling. At both experiments, seeds or seedlings were exposed to successively increasing salinity levels (0, 50, 100, 150, and 200 mM NaCl) as well as isosmotic combinations of NaCl and CaCl2 (Na+:Ca2+ of 1:1, 1:5, 1:10, 1:15, 1:18, and 1: 20), equivalent to 150 mM NaCl. Inocula of the local nitrogen-fixing bacteria, Rhizobium leguminosarum (OP715892) were supplemented at both stages. NaCl salinity exerted a negative impact on growth and metabolism of Vicia faba; inhibition was proportional with increasing salinity level up to the highest level of 200 mM. Seed germination, shoot and root lengths, fresh and dry weights, chlorophyll content, and nodules (number, weight, leghemoglobin, respiration, and nitrogenase activity) were inhibited by salinity. Ca2+ substitution for Na+, particularly at a Na/Ca ratio of 1:5, was stimulatory to almost all parameters at both stages. Statistical correlations between salinity levels and Na/Ca combinations proved one of the four levels (strong- or weak positive, strong- or weak negative) with most of the investigated parameters, depending on the parameter.

Thaumatin-like protein family genes VfTLP4-3 and VfTLP5 are critical for faba bean's response to drought stress at the seedling stage

Thaumatin-like proteins (TLPs) are a diverse family of pathogenesis-related proteins (PR-5) found in various plant species. Faba bean is an economically important crop known for its nutritional value and resilience to harsh environmental conditions, including drought. In this study, we conducted a comprehensive analysis of the gene structure, phylogenetics, and expression patterns of TLP genes in faba bean, with a specific focus on their response to drought stress. A total of 10 TLP genes were identified and characterized from the faba bean transcriptome, which could be classified into four distinct groups based on their evolutionary relationships. Conserved cysteine residues and REDDD motifs, which are characteristic features of TLPs, were found in most of the identified VfTLP members, and these proteins were likely to reside in the cytoplasm. Two genes, VfTLP4-3 and VfTLP5, exhibited significant upregulation under drought conditions. Additionally, ectopically expressing VfTLP4-3 and VfTLP5 in tobacco leaves resulted in enhanced drought tolerance and increased peroxidase (POD) activity. Moreover, the protein VfTLP4-3 was hypothesized to interact with glycoside hydrolase family 18 (GH18), endochitinase, dehydrin, Barwin, and aldolase, all of which are implicated in chitin metabolism. Conversely, VfTLP5 was anticipated to associate with peptidyl-prolyl cis-trans isomerase-like 3, a molecule linked to the synthesis of proline. These findings suggest that these genes may play crucial roles in mediating the drought response in faba bean through the regulation of these metabolic pathways, and serve as a foundation for future genetic improvement strategies targeting enhanced drought resilience in this economically important crop.

From ancient crop to modern superfood: Exploring the history, diversity, characteristics, technological applications, and culinary uses of Peruvian fava beans

The search for plant-based superfoods has shown that many regional populations already have these foods in their diet, with significant potential for production and marketing. This critical review intends to show the history, diversity, characteristics, and uses, emphasizing their significance in traditional diets and potential in the food industry of Peruvian fava beans. As a valuable plant-based protein source, fava beans offer essential micronutrients and have diverse culinary applications. Innovative food industry applications include plant-based meat alternatives, fortified gluten-free products, and a natural color, protein, and fiber source in extruded foods. Key studies have highlighted the successful incorporation of fava beans into various food products, improving their nutritional properties, though some studies also point to limitations in their sensory acceptance. Further research is needed to understand the bioactive components, health effects, and techno-functional characteristics of beans. Challenges facing cultivating and consuming fava beans in Peru include adapting to climate change, enhancing productivity and quality, and promoting consumption and added value. Addressing these challenges involves developing climate-resilient varieties, optimizing agricultural practices, and providing access to resources and financing. In conclusion, this review highlights the promising prospects of Peruvian fava beans as a sustainable, nutritionally rich, and versatile ingredient in the food industry. By harnessing their potential and overcoming challenges, Peruvian fava beans can transition from an ancient crop to a modern superfood, inspiring a global shift towards sustainable and nutritionally balanced diets, aiding the fight against malnutrition, and enriching culinary traditions worldwide.

Epigenetic modifications evidenced by isolation of proteins on nascent DNA and immunofluorescence in hydroxyurea-treated root meristem cells of Vicia faba

MAIN CONCLUSION

By implementation of the iPOND technique for plant material, changes in posttranslational modifications of histones were identified in hydroxyurea-treated root meristem cells of Vicia. Replication stress (RS) disrupts or inhibits replication forks and by altering epigenetic information of the newly formed chromatin can affect gene regulation and/or spatial organisation of DNA. Experiments on Vicia faba root meristem cells exposed to short-term treatment with 3 mM hydroxyurea (HU, an inhibitor of DNA replication) were aimed to understand epigenetic changes related to RS. To achieve this, the following histone modifications were studied using isolation of proteins on nascent DNA (iPOND) technique (for the first time on plant material) combined with immunofluorescence labeling: (i) acetylation of histone H3 at lysine 56 (H3K56Ac), (ii) acetylation of histone H4 at Lys 5 (H4K5Ac), and (iii) phosphorylation of histone H3 at threonine 45 (H3T45Ph). Certainly, the implementation of the iPOND method for plants may prove to be a key step for a more in-depth understanding of the cell's response to RS at the chromatin level.

Effects of forage and grain legume-based silages supplemented with faba bean meal or rapeseed expeller on lactational performance, nitrogen utilization, and plasma amino acids in dairy cows

The objective of this experiment was to investigate the effect of forage type [red clover (51%)-grass silage, i.e., RCG; vs. faba bean (66%)-grass silage, i.e., FBG] and concentrate type (faba bean, FB; vs. rapeseed expeller, RE) on lactational performance, milk composition and nitrogen (N) utilization in lactating dairy cows. Eight lactating multiparous Nordic Red cows were used in a replicated 4 × 4 Latin Square experiment, with 21-d periods, in a 2 × 2 factorial arrangement of treatments. The experimental treatments were as follows: (1) RCG with RE, (2) RCG with FB, (3) FBG with RE, and (4) FBG with FB. Inclusion rates of RE and FB were isonitrogenous. Crude protein contents of the experimental diets were 16.3, 15.9, 18.1, and 17.9% of dry matter, respectively. All diets included oats and barley and were fed ad libitum as total mixed rations with forage-to-concentrate ratio of 55:45. Dry matter intake and milk yield were recorded daily, and spot samples of urine, feces, and blood were collected at the end of each experimental period. Dry matter intake did not differ across diets, averaging 26.7 kg/d. Milk yield averaged 35.6 kg/d and was 1.1 kg/d greater for RCG versus FBG, and milk urea N concentration was lower for RCG compared with FBG. Milk yield was 2.2 kg/d and milk protein yield 66 g/d lower for FB versus RE. Nitrogen intake, urinary N, and urinary urea N excretions were lower, and milk N excretion tended to be lower for RCG compared with FBG. The proportion of the dietary N excreted as fecal N was larger in cows fed RCG than for those fed FBG, and the opposite was true for urinary N. We detected an interaction for milk N as percentage of N intake: it increased with RE compared with FB for RCG-based diet, but only a marginal increase was observed for FBG-based diet. Plasma concentration of His and Lys were lower for RCG than for FBG, whereas His tended to be greater and Lys lower for FB compared with RE. Further, plasma Met concentration was around 26% lower for FB than for RE. Of milk fatty acids, saturated fatty acids were decreased by RCG and increased by FB compared with FBG and RE, respectively, whereas monounsaturated fatty acids were increased by RCG versus FBG, and were lower for FB than for RE. In particular, 18:1n-9 concentration was lower for FB compared with RE. Polyunsaturated fatty acids, such as 18:2n-6 and 18:3n-3, were greater for RCG than for FBG, and 18:2n-6 was greater and 18:3n-3 was lower for FB versus RE. In addition, cis-9,trans-11 conjugated linoleic acid was lower for FB compared with RE. Faba bean whole-crop silage and faba bean meal have potential to be used as a part of dairy cow rations, but further research is needed to improve their N efficiency. Red clover-grass silage from a mixed sward, without inorganic N fertilizer input, combined with RE, resulted in the greatest N efficiency in the conditions of this experiment.

An Investigation of the Protein Quality and Temporal Pattern of Peripheral Blood Aminoacidemia following Ingestion of 0.33 g·kg-1 Body Mass Protein Isolates of Whey, Pea, and Fava Bean in Healthy, Young Adult Men

An increase in the intake of legumes is recommended in the promotion of plant-sourced (PSP) rather than animal-sourced (ASP) protein intake to produce a more sustainable diet. This study evaluated the quality of novel PSP isolates from pea (PEA) and fava bean (FAVA) and an ASP isolate of whey (WHEY) and compared the magnitude and temporal pattern of peripheral arterial aminoacidemia following ingestion of 0.33 g·kg-1 body mass of protein isolate in healthy young adult men (n = 9). Total indispensable amino acids (IAA) comprised 58% (WHEY), 46% (PEA), and 42% (FAVA) of the total amino acid (AA) composition, with the ingested protein providing 108% (WHEY), 77% (PEA), and 67% (FAVA) of the recommended per diem requirement of IAA. Reflecting the AA composition, the area under the curve (∆AUC0-180), post-ingestion increase in total IAA for WHEY was 41% (p < 0.001) and 57% (p < 0.001) greater than PEA and FAVA, respectively, with PEA exceeding FAVA by 28% (p = 0.003). As a sole-source, single-dose meal-size serving, the lower total IAA for PEA and FAVA would likely evoke a reduced post-prandial anabolic capacity compared to WHEY. Incorporated into a food matrix, the promotion of PSP isolates contributes to a more sustainable diet.

Protein blends and extrusion processing to improve the nutritional quality of plant proteins

Plant proteins have low protein nutritional quality due to their unbalanced indispensable amino acid (IAA) profile and the presence of antinutritional factors (ANFs) that limit protein digestibility. The blending of pulses with cereals/pseudocereals can ensure a complete protein source of IAA. In addition, extrusion may be an effective way to reduce ANFs and improve protein digestibility. Thereby, we aimed to improve the protein nutritional quality of plant protein ingredients by blending different protein sources and applying extrusion processing. Protein blends were prepared with pea, faba bean, quinoa, hemp, and/or oat concentrates or flours, and extrudates were prepared either rich in pulses (texturized vegetable proteins, TVPs) or rich in cereals (referred to here as Snacks). After extrusion, all samples showed a reduction in trypsin inhibitor activity (TIA) greater than 71%. Extrusion caused an increase in the total in vitro protein digestibility (IVPD) of TVPs, whereas no significant effect was shown for the snacks. According to the molecular weight distribution, TVPs presented protein aggregation. The results suggest that the positive effect of decreased TIA on IVPD is partially counteracted by the formation of aggregates during extrusion which restricts enzyme accessibility. After extrusion, all snacks retained a balanced amino acid score whereas a small loss of methionine + cysteine was observed in the TVPs, resulting in a small reduction in IAA content. Thus, extrusion has the potential to improve the nutritional quality of TVPs by reducing TIA and increasing protein digestibility.

Response of Vicia faba to short-term uranium exposure: chelating and antioxidant system changes in roots

Uranium (U) phytotoxicity is an inherently difficult problem in the phytoremediation of U-contaminated environments. Plant chelating and antioxidant systems play an authoritative role in resistance to abiotic stress. To reveal the toxicity of U, the changes of chelating system, osmoregulatory substances and antioxidant systems in Vicia faba roots were studied after short-term (24 h) U exposure. The results indicated that the development of lateral roots and root activity of V. faba were significantly inhibited with U accumulation. Compared with the control, plant chelating systems showed significant positive effects after U exposure (15 - 25 μM). Osmoregulatory substances (proline and soluble protein) increasingly accumulated in roots with increasing U concentration, and O2- and H2O2 rapidly accumulated after U exposure (15 - 25 μM). Thus, the contents of malondialdehyde (MDA), a marker of lipid peroxidation, were also significantly increased. Antioxidant systems were activated after U exposure but were inhibited at higher U concentrations (15 - 25 μM). In summary, although the chelating, osmotic regulation and antioxidant systems in V. faba were activated after short-term U exposure, the antioxidases (CAT, SOD and POD) were inhibited at higher U concentrations (15 - 25 μM). Therefore, the root cells were severely damaged by peroxidation, which eventually resulted in inhibited activity and arrested root development.

Processed fava bean as a substitute for rapeseed meal with or without rumen-protected methionine supplement in grass silage-based dairy cow diets

Fava bean offers a sustainable home-grown protein source for dairy cows, but fava bean protein is extensively degraded in the rumen and has low Met concentration. We studied the effects of protein supplementation and source on milk production, rumen fermentation, N use, and mammary AA utilization. The treatments were unsupplemented control diet, and isonitrogenously given rapeseed meal (RSM), processed (dehulled, flaked, and heated) fava bean without (TFB) or with rumen-protected (RP) Met (TFB+). All diets consisted of 50% grass silage and 50% cereal-based concentrate including studied protein supplement. The control diet had 15% of crude protein and protein-supplemented diets 18%. Rumen-protected Met in TFB+ corresponded to 15 g/d of Met absorbed in the small intestine. Experimental design was a replicated 4 × 4 Latin square with 3-wk periods. The experiment was conducted using 12 multiparous mid-lactation Nordic Red cows, of which 4 were rumen cannulated. Protein supplementation increased dry matter intake (DMI), and milk (31.9 vs. 30.7 kg/d) and milk component yields. Substituting RSM with TFB or TFB+ decreased DMI and AA intake but increased starch intake. There were no differences in milk yield or composition between RSM diet and TFB diets. Rumen-protected Met did not affect DMI, or milk or milk component yields but increased milk protein concentration in comparison to TFB. There were no differences in rumen fermentation except for increased ammonium-N concentration with the protein-supplemented diets. Nitrogen-use efficiency for milk production was lower for the supplemented diets versus control diet but tended to be greater for TFB and TFB+ versus RSM. Protein supplementation increased plasma essential AA concentration but there were no differences between TFB diets and RSM. Rumen-protected Met clearly increased plasma Met concentration (30.8 vs. 18.2 µmol/L) but did not affect other AA. Absence of differences between RSM and TFB in milk production together with limited effects of RP Met suggest that TFB is a potential alternative protein source for dairy cattle.

The giant diploid faba genome unlocks variation in a global protein crop

Increasing the proportion of locally produced plant protein in currently meat-rich diets could substantially reduce greenhouse gas emissions and loss of biodiversity1. However, plant protein production is hampered by the lack of a cool-season legume equivalent to soybean in agronomic value2. Faba bean (Vicia faba L.) has a high yield potential and is well suited for cultivation in temperate regions, but genomic resources are scarce. Here, we report a high-quality chromosome-scale assembly of the faba bean genome and show that it has expanded to a massive 13 Gb in size through an imbalance between the rates of amplification and elimination of retrotransposons and satellite repeats. Genes and recombination events are evenly dispersed across chromosomes and the gene space is remarkably compact considering the genome size, although with substantial copy number variation driven by tandem duplication. Demonstrating practical application of the genome sequence, we develop a targeted genotyping assay and use high-resolution genome-wide association analysis to dissect the genetic basis of seed size and hilum colour. The resources presented constitute a genomics-based breeding platform for faba bean, enabling breeders and geneticists to accelerate the improvement of sustainable protein production across the Mediterranean, subtropical and northern temperate agroecological zones.

Study of the competition between Pi and Cr (VI) for the use of Pi-transporter at Vicia faba L. using molecular modeling

Recent studies have shown that Cr uses other element transporters such as phosphate transporters to enter cells. The aim of this work is to explore the interaction between dichromate and inorganic phosphate (Pi) in the plant of Vicia faba L. To study this interaction, we used three concentrations of Dipotassium hydrogen phosphate (K₂HPO₄) 10 mM (Pi10), 50 mM (Pi50) and 100 mM (Pi100) added alone or in combination with potassium dichromate (K₂Cr₂O₇) Cr + Pi10, Cr + Pi50 and Cr + Pi100. In order to investigate the impact of this interaction on morpho-physiological parameters, the biomass, chlorophyll content, proline level, H₂O₂ level, Catalase and Ascorbate peroxidase activity and Cr-bioaccumulation has been determined. For the molecular scale, the theoretical chemistry was used via molecular docking to explore the various interactions between dichromate Cr₂O₇^2-/HPO₄^2-/H₂O₄P^- and the phosphate-transporter. We have selected the eukaryotic phosphate transporter (PDB: 7SP5) as the module. The results showed that K₂Cr₂O₇ negatively affects morpho-physiological parameters and generates oxidative damage (+84% H₂O₂ than the control), which involved the production of antioxidant enzymes (+147% Catalase and +176% Ascorbate-peroxidase) and Proline (+108%). The addition of Pi improved the growth of Vicia faba L. and induces the partial restoration of the parameters affected by Cr (VI) to the normal levels. Also, it decreased oxidative damage and reduce Cr (VI) bioaccumulation in shoots and roots. Molecular docking has shown that the dichromate structure is more compatible and establishes more bonds with the Pi-transporter which generates a very stable complex compared to HPO₄^2-/H₂O₄P^-. Overall, these results confirmed that there is a strong relationship between dichromate uptake and the Pi-transporter.

Comparison of standardized ileal digestibility of amino acids in faba beans and field peas in broiler chickens and pigs

An experiment, using the same set of five diets was conducted to determine and compare the standardized ileal digestibility (SID) of amino acids (AA) in faba beans and three cultivars of field peas in broiler chickens and pigs. Four test diets were prepared to contain faba beans, DS-Admiral field peas, Hampton field peas, or 4010 field peas as the sole source of nitrogen. A nitrogen-free diet (NFD), as the fifth diet, was prepared to estimate the basal endogenous losses of AA to determine the SID of AA in the test ingredients. A total of 416 male broiler chickens with an initial body weight (BW) of 951 ± 111 g were allotted to five diets in a randomized complete block design with BW as a blocking factor on day 21 posthatching. There were 8 replicate cages with 10 birds per cage for diets containing test ingredients and 12 birds per cage for NFD. All birds were allowed ad-libitum access to feed for 5 days. On day 26 posthatching, all birds were euthanized by CO2 asphyxiation and digesta contents were collected from the distal two-thirds of the ileum. Twenty barrows with an initial BW of 30.2 ± 1.58 kg, surgically fitted with T-cannulas in the distal ileum, were divided into four blocks according to BW and each block was assigned to a 5 × 2 incomplete Latin Square design that consisted of five dietary treatments and two experimental periods. For each experimental period, there was a 5-day adaptation period followed by a 2-day collection of ileal digesta samples. The data were analyzed as a 2 × 4 factorial treatment arrangement with the effect of species (i.e., broiler chickens and pigs) and test diets (i.e., four test ingredients). For broiler chickens, the SID of Lys in faba beans, DS-Admiral field peas, and Hampton field peas were above 90% but in 4010 field peas, it was 85.1%. The SID of Lys in faba beans, DS-Admiral field peas, and Hampton field peas for pigs was above 80% but was 78.9% in 4010 field peas. The respective SID of Met in faba beans, DS-Admiral field peas, Hampton field peas, and 4010 field peas were 84.1%, 87.3%, 89.8%, and 72.1% for broiler chickens, and 71.5%, 80.4%, 81.8%, and 68.1% for pigs. The SID of AA in 4010 field peas was the least (P < 0.05) for chickens, but in pigs, it was comparable with faba beans. In conclusion, the SID of AA in faba beans and field peas was greater in broiler chickens compared with pigs and there was a cultivar effect.

Lower Non-Heme Iron Absorption in Healthy Females from Single Meals with Texturized Fava Bean Protein Compared to Beef and Cod Protein Meals: Two Single-Blinded Randomized Trials

Meat analogs based on plant protein extracts are rising in popularity as meat consumption declines. A dietary shift away from meat, which has a high iron bioavailability, may have a negative effect on the amount of iron absorbed from the diet. Iron absorption from legumes cultivated in regions not suitable for soy production, such as fava bean, has not yet been explored. The aim of this study was to evaluate non-heme iron absorption from a meal with texturized fava bean protein compared to beef and cod protein meals. The study included two single-blinded iron isotope trials in healthy Swedish women of the ages 18–45 years, each of whom served as their own control. The participants were served matched test meals containing beef and fava bean protein (Study 1) or cod and fava bean protein (Study 2) with radiolabeled non-heme iron 55Fe and 59Fe. The absorption of non-heme iron from test meals was measured by whole-body counting and erythrocyte incorporation. The absorption of non-heme iron, measured as erythrocyte incorporation ratio, from beef protein meal was 4.2 times higher compared to texturized fava bean meal, and absorption from cod protein meal was 2.7 times higher compared to the fava bean meal. The adjusted non-heme iron absorption, normalized to a 40% reference dose uptake, was 9.2% for cod protein meal, 21.7% for beef protein meal, and 4.2% for texturized fava bean meal. A fava bean protein meal has markedly lower iron bioavailability in healthy females compared with a meal of beef or cod protein. Therefore, a dietary shift from meat and fish protein to fava bean protein may increase the risk of iron deficiency.

[Effect of intercropping with Vicia faba on secondary metabolites and rhizosphere soil microbial diversity of Notopterygium incisum]

Rhizosphere soil microbial community and its diversity are important for the structure and functions of medicinal plant ecosystem. In this study, based on high-throughput sequencing, rhizosphere soil microbial diversity, and yield and quality of rhizome and root of Notopterygium incisum cultivated alone(control, CK) and intercropped with Vicia faba(QH) were analyzed, which is expected to lay a basis for optimization of the cultivation mode and ecological production of N. incisum. RESULTS:: showed that the rhizosphere soil bacteria of N. incisum were dominated by Proteobacteria and Bacteroides, with the relative abundance of 50.38%-51.95% and 16.36%-17.02%, respectively. Soil bacterial community at the phylum level was not significantly different between CK and QH. At the genus level, the relative abundance of MND1(3.54%), Spinstomonas(3.50%), Nitrospira(1.53%), and Rhizobacter(1.05%) was significantly higher and that of Gemmatimonas, Candidatus＿Solibacter, and Bryophytes was lower in QH treatment than in the CK. The plant height, leaf length, leaf width, and petiole length of N. incisum in QH treatment was significantly increased and the underground biomass rose by 71.43% compared with those in the CK. Thus, intercropping with V. faba promoted the aboveground growth of N. incisum and improved the yield of root and rhizome. Moreover, the content of notopterol and isoimperatorin increased by 37.96% and 4.09% in QH treatment, respectively, indicating that the intercropping with V. faba boosted the accumulation of secondary metabolites in N. incisum. Pearson's correlation analysis showed that the soil bacterial community was mainly influenced by the soil factors including the content of soil available nutrients, soil organic matter, pH value, and soil water. The influence was in the order: total potassium&gt;total nitrogen&gt;pH&gt;organic matter&gt;available potassium&gt;soil water content&gt;available nitrogen&gt;available phosphorus. In conclusion, the intercropping with V. faba altered soil microenvironment and also increased the yield and accumulation of secondary metabolites of N. incisum, which is a promising ecological planting model for N. incisum.

Amino acid digestibility and metabolisable energy of spring and winter faba beans grown on two sites and effects of dehulling in caecectomised laying hens

BACKGROUND

The variation in amino acid (AA) digestibility and metabolisable energy (ME_N ) in four spring and four winter faba bean genotypes differing in vicine/convicine (V/C) concentrations grown on two sites was investigated in caecectomised LSL-Classic laying hens. Effects of dehulling one faba bean genotype were also examined. Diets containing one out of 17 faba bean variants each and a basal diet were fed to ten caecectomised laying hens in a row-column design to achieve five replicates per diet.

RESULTS

Ranges and levels of digestibility of the hulled variants differed widely among AA with the lowest and highest range determined for Arg (90-93%) and Cys (-12-65%), respectively. ME_N ranged between 10.3 and 12.3 MJ kg^-1 dry matter. Lower ME_N and digestibility of Cys, Glx, Phe, Pro, Tyr, and Val (P < 0.050) was determined for the winter genotypes grown in Nimtitz compared to the other variants. Digestibility of Ser was lower for the spring than for the winter genotypes (P < 0.050). Negative correlations with AA digestibility were determined for phytate, but not for tannin and V/C concentrations (P < 0.050). Negative correlations between tannin fractions and ME_N were weak (P = 0.082-0.099). Dehulling increased ME_N by 1.8 MJ kg^-1 dry matter and raised the digestibility of Pro, His, and Glx (P < 0.050).

CONCLUSIONS

The results indicated that the digestible AA and ME_N supply of laying hens was increased by using low phytate faba beans while breeding for low V/C genotypes did not affect AA digestibility or ME_N . Dehulling increased ME_N and the digestibility of some AA. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Acute hemolysis and methemoglobinemia secondary to fava beans ingestion in a patient with G6PD deficiency: A case report of a rare co-occurrence

RATIONALE

Favism is a well-known cause of acute hemolytic anemia. Rarely, methemoglobinemia can also happen because of fava bean ingestion in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Few cases with this co-occurrence have been reported in the literature.

PATIENT CONCERNS

We report a case of a 47-year-old patient who presented with jaundice that started 2 days after eating fava beans.

DIAGNOSES

Laboratory investigations revealed anemia with evidence of hemolysis (high reticulocytes count, high indirect bilirubin, bite cells in peripheral smear). Blood gases showed high methemoglobin level. Reduced level of G6PD enzyme confirmed the diagnosis of G6PD deficiency.

INTERVENTION

The patient was kept on supplemental oxygen. He was counselled to avoid food and drugs that can cause acute hemolysis.

OUTCOMES

Oxygen saturation improved gradually. The patient was discharged without any complications after 2 days.

LESSONS

Patients with G6PD deficiency can develop both acute hemolytic anemia and methemoglobinemia secondary to fava beans ingestion. These patients should not receive methylene blue to avoid worsening hemolysis.

Ester synthesis mechanism and activity by Bacillus licheniformis, Candida etchellsii, and Zygosaccharomyces rouxii isolated from Chinese horse bean chili paste

BACKGROUND

Esters are indispensable aroma compounds and contribute significantly to the fruity aromas in fermented condiments. The ester synthesis activity and pathways of Bacillus licheniformis, Candida etchellsii, and Zygosaccharomyces rouxii, isolated from Chinese horse bean chili-paste (CHCP), were investigated. Chemical buffer models containing esterification and alcoholysis systems inoculated with extracellular extracts of these three strains were established.

RESULTS

The ester synthesis activity of C. etchellsii was stronger than that of the other two strains. Zygosaccharomyces rouxii could synthesize acetate esters via esterification, whereas the biosynthesis pathways of B. licheniformis and C. etchellsii were esterification and alcoholysis. Esterification exhibited relatively high activity at pH 4, whereas alcoholysis activity improved with an increase in the pH from 4 to 8. Candida etchellsii could synthesize C₆ -C₈ of acetate esters, and its activity improved with the number of alcohol carbon atoms. These three strains could synthesize C₁₀ -C₁₈ of ethyl esters. Their ethyl ester synthesis activity decreased with the aliphatic acid carbon number.

CONCLUSION

Candida etchellsii has the potential to be used in CHCP fermentation to accumulate esters and improve flavor compared with the other two strains. This research is helpful in explaining the mechanism of ester synthesis in fermented condiments. © 2021 Society of Chemical Industry.

Morphological, Biochemical and Molecular Characterization of Rhizobia of Faba Bean Plants Grown in North Nile Delta Egypt

&lt;b&gt;Background and Objective:&lt;/b&gt; Rhizobia are bacteria including genes codes for enzymes involved in the fixing of the atmospheric nitrogen. A set of twenty rhizobial isolates were studied to determine their morphological, biochemical, molecular characteristics using the 16S rRNA gene in addition to assess their growth and symbiotic performance. &lt;b&gt;Materials and Methods:&lt;/b&gt; Rhizobial isolates were isolated from root nodules of &lt;i&gt;Vicia faba &lt;/i&gt;L. plants. The isolates were morphologically characterized by determining cell shapes, size, Gram stain reaction, motility, sporulation, bacterial growth performance was determined by IAA production and biomass density. Symbiotic performance was measured by evaluation of nodulation status and shoot/root dry weight. Sequencing of 16S rRNA and phylogenetic analysis were done for the five promising isolates. Statistical analysis was performed using a one-sample Student t-test. &lt;b&gt;Results:&lt;/b&gt; Only five rhizobial isolates (Rh 32, Rh 6-A, Rh 3-4, Rh RL3 and Rh 8-A) were selected according to their growth and symbiotic performance and subjected to further molecular characterizations. All isolates were found to have remarkable nodulation status, IAA production, nitrogenase activity and increasing the root and shoot dry weight. The five selected rhizobial isolates were identified by partial sequencing of 16S rRNA genes and registered in the GenBank database. The alignment and phylogenetic analyses of 16S rRNA sequences closely related in the GenBank revealed that all isolates belonging to &lt;i&gt;Rhizobium leguminosarum&lt;/i&gt; bv. viciae. &lt;b&gt;Conclusion:&lt;/b&gt; The results confirmed that the five Rhizobial strains will be promising as a source of genes for nitrogen fixation and plant growth promotion.

Paternal outcrossing success differs among faba bean genotypes and impacts breeding of synthetic cultivars

Faba bean genotypes showed significant and marked genetic differences in their success as pollen donors to cross-fertilized seeds. The findings may improve exploitation of heterosis in synthetic cultivars. In partially allogamous crops such as faba bean (Vicia faba L.), increasing the share of heterosis in a synthetic cultivar can improve yield and yield stability. The share of heterosis in such synthetic cultivars is increased by higher degrees of cross-fertilization. This trait is defined as percentage of cross-fertilized seeds among all seeds and is a crucial parameter in breeders' yield predictions. Current approaches use degree of cross-fertilization to predict inbreeding and share of heterosis, they even consider genotype-specific degrees; yet, all genotypes are assumed to contribute equally to the cross-fertilized seeds. Here, we expect faba bean genotypes to differ in their success rates as pollen donors, i.e. in paternal outcrossing success. To quantify the variation of both, the degree of cross-fertilization and the paternal outcrossing success, we assessed these parameters in inbred lines and F1 hybrids, grown in four polycrosses composed of eight genotypes each. We identified the paternal genotype of 500 to 800 seeds per genotype and polycross using SNP markers. In both traits, we found marked and significant variation among inbred lines and among F1 hybrids, as well as between inbred lines and F1. Based on our findings, we discuss how differential paternal outcrossing success influences the amount of inbreeding in synthetic cultivars. Our findings offer the potential for a better management and exploitation of heterotic yield increase in faba bean.

VC1 catalyses a key step in the biosynthesis of vicine in faba bean

Faba bean (Vicia faba L.) is a widely adapted and high-yielding legume cultivated for its protein-rich seeds¹. However, the seeds accumulate the pyrimidine glucosides vicine and convicine, which can cause haemolytic anaemia (favism) in 400 million genetically predisposed individuals². Here, we use gene-to-metabolite correlations, gene mapping and genetic complementation to identify VC1 as a key enzyme in vicine and convicine biosynthesis. We demonstrate that VC1 has GTP cyclohydrolase II activity and that the purine GTP is a precursor of both vicine and convicine. Finally, we show that cultivars with low vicine and convicine levels carry an inactivating insertion in the coding sequence of VC1. Our results reveal an unexpected, purine rather than pyrimidine, biosynthetic origin for vicine and convicine and pave the way for the development of faba bean cultivars that are free of these anti-nutrients.

VC1 catalyses a key step in the biosynthesis of vicine in faba bean

Faba bean (Vicia faba L.) is a widely adapted and high-yielding legume cultivated for its protein-rich seeds¹. However, the seeds accumulate the pyrimidine glucosides vicine and convicine, which can cause haemolytic anaemia (favism) in 400 million genetically predisposed individuals². Here, we use gene-to-metabolite correlations, gene mapping and genetic complementation to identify VC1 as a key enzyme in vicine and convicine biosynthesis. We demonstrate that VC1 has GTP cyclohydrolase II activity and that the purine GTP is a precursor of both vicine and convicine. Finally, we show that cultivars with low vicine and convicine levels carry an inactivating insertion in the coding sequence of VC1. Our results reveal an unexpected, purine rather than pyrimidine, biosynthetic origin for vicine and convicine and pave the way for the development of faba bean cultivars that are free of these anti-nutrients.

Agroinfiltration for transient gene expression and characterisation of fungal pathogen effectors in cool-season grain legume hosts

KEY MESSAGE

Modified pEAQ-HT-DEST1 vectors were used for agroinfiltration in legumes. We demonstrate protein expression and export in pea, lentil, and faba bean; however, the method for chickpea was not successful. Agroinfiltration is a valuable research method for investigating virulence and avirulence effector proteins from pathogens and pests, where heterologous effector proteins are transiently expressed in plant leaves and hypersensitive necrosis responses and other effector functions can be assessed. Nicotiana benthamiana is widely used for agroinfiltration and the characterisation of broad-spectrum effectors. The method has also been used in other plant species including field pea, but not yet developed for chickpea, lentil, or faba bean. Here, we have modified the pEAQ-HT-DEST1 vector for expression of 6 × histidine-tagged green-fluorescent protein (GFP) and the known necrosis-inducing broad-spectrum effector necrosis and ethylene-inducing peptide (Nep1)-like protein (NLP). Modified pEAQ-based vectors were adapted to encode signal peptide sequences for apoplast targeting of expressed proteins. We used confocal microscopy to assess the level of GFP expression in agroinfiltrated leaves. While at 3 days after infiltration in N. benthamiana, GFP was expressed at a relatively high level, expression in field pea and faba bean at the same time point was relatively low. In lentil, an expression level of GFP similar to field pea and faba bean at 3 days was only observed after 5 days. Chickpea leaf cells were transformed at low frequency and agroinfiltration was concluded to not be successful for chickpea. We concluded that the pEAQ vector is suitable for testing host-specific effectors in field pea, lentil, and faba bean, but low transformation efficiency limits the utility of the method for chickpea.

GABA signalling modulates stomatal opening to enhance plant water use efficiency and drought resilience

The non-protein amino acid γ-aminobutyric acid (GABA) has been proposed to be an ancient messenger for cellular communication conserved across biological kingdoms. GABA has well-defined signalling roles in animals; however, whilst GABA accumulates in plants under stress it has not been determined if, how, where and when GABA acts as an endogenous plant signalling molecule. Here, we establish endogenous GABA as a bona fide plant signal, acting via a mechanism not found in animals. Using Arabidopsis thaliana, we show guard cell GABA production is necessary and sufficient to reduce stomatal opening and transpirational water loss, which improves water use efficiency and drought tolerance, via negative regulation of a stomatal guard cell tonoplast-localised anion transporter. We find GABA modulation of stomata occurs in multiple plants, including dicot and monocot crops. This study highlights a role for GABA metabolism in fine tuning physiology and opens alternative avenues for improving plant stress resilience.

Effects of marine biofertilisation on Celtic bean carbon, nitrogen and sulphur isotopes: Implications for reconstructing past diet and farming practices

RATIONALE

The application of fertilisers to crops can be monitored and assessed using stable isotope ratios. However, the application of marine biofertilisers (e.g., fish, macroalgae/seaweed) on crop stable isotope ratios has been rarely studied, despite widespread archaeological and historical evidence for the use of marine resources as a soil amendment.

METHODS

A heritage variety of Celtic bean, similar in size and shape to archaeobotanical macrofossils of Vicia faba L., was grown in three 1 × 0.5 m outdoor plots under three soil conditions: natural soil (control); natural soil mixed with macroalgae (seaweed); and 15 cm of natural soil placed on a layer of fish carcasses (Atlantic cod). These experiments were performed over two growing seasons in the same plots. At the end of each growing season, the plants were sampled, measured and analysed for carbon, nitrogen and sulphur stable isotope ratios (δ¹³ C, δ¹⁵ N, δ³⁴ S).

RESULTS

The bean plants freely uptake the newly bioavailable nutrients (nitrogen and sulphur) and incorporate a marine isotopic ratio into all tissues. The bean δ¹⁵ N values ranged between 0.8‰ and 1.0‰ in the control experiment compared with 2‰ to 3‰ in the macroalgae crop and 8‰ to 17‰ in the cod fish experiment. Their δ³⁴ S values ranged between 5‰ and 7‰ in the control compared with 15‰ to 16‰ in the macroalgae crop and 9‰ to 12‰ in the cod fish crop. The beans became more ¹³ C-depleted (δ¹³ C values: 1-1.5‰ lower) due to crop management practices.

CONCLUSIONS

Humans and animals consuming plants grown with marine biofertilisers will incorporate a marine signature. Isotopic enrichment in nitrogen and sulphur using marine resources has significant implications when reconstructing diets and farming practices in archaeological populations.

Metabolic profiling reveals alterations in the erythrocyte response to fava bean ingestion in G6PD-deficient mice

BACKGROUND

Favism is an acute hemolytic syndrome caused by fava bean (FB) ingestion. The purpose of this study was to investigate the possible influences of FB on the metabonomic profile of erythrocytes in glucose-6-phosphate dehydrogenase (G6PD)-deficient (G6PDx) and wild-type (WT) mice.

RESULTS

Ninety-two metabolites were identified in the comparison of the G6PDx and WT groups. Eighty-seven metabolites were identified in the erythrocytes of WT and G6PDx mice after FB ingestion. Thirty-eight metabolites were identified in the comparison of the FB-treated G6PDx and the FB-treated WT mouse groups. Among them, the number of glycerophospholipids (GPLs) and polyunsaturated fatty acids (PUFAs) changed significantly, which suggests that GPLs and PUFAs may be responsible for FB stress.

CONCLUSION

This study demonstrates that G6PD deficiency might affect the metabonomic profile of erythrocytes in response to FB. © 2020 Society of Chemical Industry.

Acclimatisation of guard cell metabolism to long-term salinity

Stomatal movements are enabled by changes in guard cell turgor facilitated via transient accumulation of inorganic and organic ions imported from the apoplast or biosynthesized within guard cells. Under salinity, excess salt ions accumulate within plant tissues resulting in osmotic and ionic stress. To elucidate whether (a) Na⁺ and Cl^- concentrations increase in guard cells in response to long-term NaCl exposure and how (b) guard cell metabolism acclimates to the anticipated stress, we profiled the ions and primary metabolites of leaves, the apoplast and isolated guard cells at darkness and during light, that is, closed and fully opened stomata. In contrast to leaves, the primary metabolism of guard cell preparations remained predominantly unaffected by increased salt ion concentrations. Orchestrated reductions of stomatal aperture and guard cell osmolyte synthesis were found, but unlike in leaves, no increases of stress responsive metabolites or compatible solutes occurred. Diverging regulation of guard cell metabolism might be a prerequisite to facilitate the constant adjustment of turgor that affects aperture. Moreover, the photoperiod-dependent sucrose accumulation in the apoplast and guard cells changed to a permanently replete condition under NaCl, indicating that stress-related photosynthate accumulation in leaves contributes to the permanent closing response of stomata under stress.

Study on the stereoselective behaviors of fosthiazate stereoisomers in legume vegetables by supercritical fluid chromatography-tandem mass spectrometry (SFC-MS/MS)

A separation and analysis method of fosthiazate stereoisomers was established utilizing supercritical fluid chromatography-tandem mass spectrometry (SFC-MS/MS) with a CHIRALPAK AD-3 column. The determination of the four fosthiazate stereoisomers could be completed within 6 min. The environmental behaviors of fosthiazate stereoisomers were studied in legume vegetables. After applying fosthiazate granules to soil, the concentrations of fosthiazate stereoisomers in the legume vegetables increased with time, reached maximum values in 7-10 days, and then decreased gradually in all legumes except for in Glycine max. No obvious dissipation behaviors were observed in Glycine max. Interestingly, the stereoselective behaviors were species-specific. A-(-), B-(-) and B-(±)-fosthiazate were preferentially enriched in Phaseolus vulgaris Linn and Vigna unguiculata, while A-(+) and A-(±)-fosthiazate preferentially accumulated in Vicia faba Linn, Pisum sativum Linn and G. max. The opposite stereoselectivity of B-(±)-fosthiazate was observed in different growth stage of G. max. No stereoselective dissipation occurred in soil.

Protective Role of Native Rhizospheric Soil Microbiota Against the Exposure to Microcystins Introduced into Soil-Plant System via Contaminated Irrigation Water and Health Risk Assessment

Microcystins (MCs) produced in eutrophic waters may decrease crop yield, enter food chains and threaten human and animal health. The main objective of this research was to highlight the role of rhizospheric soil microbiota to protect faba bean plants from MCs toxicity after chronic exposure. Faba bean seedlings were grown in pots containing agricultural soil, during 1 month under natural environmental conditions of Marrakech city in Morocco (March–April 2018) and exposed to cyanobacterial extracts containing up to 2.5 mg·L⁻¹ of total MCs. Three independent exposure experiments were performed (a) agricultural soil was maintained intact “exposure experiment 1”; (b) agricultural soil was sterilized “exposure experiment 2”; (c) agricultural soil was sterilized and inoculated with the rhizobia strain Rhizobium leguminosarum RhOF34 “exposure experiment 3”. Overall, data showed evidence of an increased sensitivity of faba bean plants, grown in sterilized soil, to MCs in comparison to those grown in intact and inoculated soils. The study revealed the growth inhibition of plant shoots in both exposure experiments 2 and 3 when treated with 2.5 mg·L⁻¹ of MCs. The results also showed that the estimated daily intake (EDI) of MCs, in sterilized soil, exceeded 2.18 and 1.16 times the reference concentrations (0.04 and 0.45 µg of microcysin-leucine arginine (MC-LR). Kg⁻¹ DW) established for humans and cattle respectively, which raises concerns about human food chain contamination.

Functional and Rheological Properties of Vicia faba L. Protein Isolates

A protein isolate (85.5%) was obtained from the Vicia faba L. seeds. The main protein fraction, typical for the seeds of this plant, was found to be most numerous: Legumin (35 kDa) and Vicilin (45 kDa). The hydrodynamic and surface properties of isolate aqueous solutions were studied with the help of dynamic light scattering, ζ-potential, and tensometry in a wide range of concentrations and pH conditions. Selected functional properties, like foaming and emulsifying abilities, were studied. An increase of water solubility was shown with a raising pH, as well as a water holding capacity (WHC). The protein isolate showed a tendency to decrease the surface tension of water solutions, with high hydrophobicity and a negative charge of the isolate enhancing the foaming and emulsifying properties. The analysis of the concentration and the pH influence on selected functional properties indicated alkaline conditions as favorable for good foaming and emulsifying properties of the isolate and affected on their rheological properties.

Species-Specific and Distance-Dependent Dispersive Behaviour of Forisomes in Different Legume Species

Forisomes are giant fusiform protein complexes composed of sieve element occlusion (SEO) protein monomers, exclusively found in sieve elements (SEs) of legumes. Forisomes block the phloem mass flow by a Ca2+-induced conformational change (swelling and rounding). We studied the forisome reactivity in four different legume species-Medicago sativa, Pisum sativum, Trifolium pratense and Vicia faba. Depending on the species, we found direct relationships between SE diameter, forisome surface area and distance from the leaf tip, all indicative of a developmentally tuned regulation of SE diameter and forisome size. Heat-induced forisome dispersion occurred later with increasing distance from the stimulus site. T. pratense and V. faba dispersion occurred faster for forisomes with a smaller surface area. Near the stimulus site, electro potential waves (EPWs)-overlapping action (APs), and variation potentials (VPs)-were linked with high full-dispersion rates of forisomes. Distance-associated reduction of forisome reactivity was assigned to the disintegration of EPWs into APs, VPs and system potentials (SPs). Overall, APs and SPs alone were unable to induce forisome dispersion and only VPs above a critical threshold were capable of inducing forisome reactions.

Rice Straw Biochar Application and its Impact on Yield of Some Faba Bean Varieties in Sandy Soil

&lt;b&gt;Background and Objective:&lt;/b&gt; Biological fertilization in the development of agriculture became one new strategy in the increased production of field crops to decrease the costs of production input and environmental pollution. This study focused on the influence of biochar fertilization on the productivity of faba bean varieties under sandy soils. &lt;b&gt;Materials and Methods:&lt;/b&gt; Appreciation of the yield and its components, in addition to measurement of grain protein content as well as carbohydrates (%) of faba bean. &lt;b&gt;Results:&lt;/b&gt; The data obtained indicated that the biochar amendment affects plant production at different rates, where the best yield obtained is 90 kg fed&lt;sup&gt;1&lt;/sup&gt;. The grain yield increase is significant for the variety's types where, Mariout-2, followed by Nubaria-3 followed by Giza-716 for the addition of 90 kg fed&lt;sup&gt;1&lt;/sup&gt; of biochar as referenced by the non-conditioning treatment. Likewise, the protein content was highest in the Mariout-2 variety, followed by Nubaria-3 variety and Giza-716 variety for the addition. This improvement may be regarded to the impact of biochar on the physic-chemical characteristics for the soils, in addition to the biological characteristics. Furthermore, the biochar itself add nutrient to the soil after decomposition. The best improvement happens by the long-term cropping for a long period could be reached up to years. &lt;b&gt;Conclusion:&lt;/b&gt; The conclusion that plant growth was better at a high rate (90 kg fed&lt;sup&gt;1&lt;/sup&gt;) but the economy of this rate may be questioned, under the condition of the study. However, the validation for different soils may vary with different rates, which needs more research. Also, it is recommended to use Mariout-2 cultivars for their high production under these conditions.

Cadmium accumulation in oilseed rape is promoted by intercropping with faba bean and ryegrass

The mechanisms of intercropping increasing plant biomass, cadmium accumulation, and organic acids secreted in rhizosphere soil are still unclear. Oilseed rape and intercrops were grown in boxes separated either with no barrier between the compartments or by a nylon mesh barrier (37 μm) to license partial root interaction, or a solid barrier to stop any root interactions. Two intercropping systems (oilseed rape-faba bean and oilseed rape-ryegrass) were carried out in soil with Cd content of 5 mg/kg. The intermingling of roots between oilseed rape and faba bean enhanced the biomass of oilseed rape. However, the biomass was negatively affected implying the higher nutrient apportionment to the ryegrass than oilseed rape. Oilseed rape intercropping with both faba bean and ryegrass played a positive role in the shoot Cd concentration of oilseed rape. The intermingling of roots played a positive role in the citric and malic acids when intercropping with faba bean. A remarkable increase in water-soluble Cd and DTPA-Cd content was observed during oilseed rape-faba bean complete root interaction treatment, up to 175.00% and 46.65%, respectively, which compare with the monoculture treatment. In both systems, the translocation factor values were higher for oilseed rape (O-F system) than for the other test plants and were always >1. Thus the Cd removal potential of oilseed rape can be further improved in the future by optimizing agronomic practices and intercropping with faba bean.

Influence of the plant interacting entomopathogenic fungus Beauveria bassiana on parasitoid host choice-behavior, development, and plant defense pathways

Inoculating plants with entomopathogenic fungi may influence plant nutrient uptake and growth, and herbivore performance. Knowledge is limited concerning the effects of this symbiosis on higher trophic levels. We examined how fungal treatment of faba bean seeds with the entomopathogenic fungus Beauveria bassiana influenced the choice-behavior and development of the aphid parasitoid Aphidius colemani. We also sampled plant material for analysis of changes in expression of genes related to plant defense pathways. While parasitoids were compatible with plants inoculated with B. bassiana initially (66 vs. 65% parasitization on inoculated and control plants, respectively; similar development times of parasitoids: 9.2 days), the emergence of adult parasitoids originating from aphids on fungus treated plants was significantly lower (67 vs. 76%, respectively). We also found that the defense response changed, similar to induced systemic resistance, when plants were treated with B. bassiana, similarly to what has been found for other plant symbiotic microorganisms. These novel findings show that although the application of entomopathogenic fungi to plants can alter the plants' defense against herbivores, it may also have an impact on beneficial insects, so their function and use should be evaluated on a case-by-case basis.

The bHLH transcription factor VfTT8 underlies zt2, the locus determining zero tannin content in faba bean (Vicia faba L.)

Faba bean (Vicia faba L.) is an important protein-rich fodder crop, which is widely cultivated in temperate areas. However, antinutritional compounds such as condensed tannins, limit the use of this protein source in monogastric feed formulations. Previous studies demonstrated that two recessive and complementary genes, zt1 and zt2, control absence of tannin and white flower colour in faba bean. An ortholog of the Medicago WD40 transcription factor TTG1 was reported to encode the zt1 phenotype, but the responsible gene for zt2 is still unknown. Here we used a candidate gene approach combined with linkage mapping, comparative genomics and gene expression to fine map the zt2 genomic region and to identify the regulatory gene controlling both traits. Seventy-two genes, including 23 MYB and bHLH regulatory genes predicted to be associated with anthocyanin expression together with WRKY proteins, were screened and genotyped in three mapping populations. The linkage groups constructed identified the regulatory gene, TRANSPARENT TESTA8 (TT8), encoding a basic helix-loop-helix (bHLH) transcription factor, as the candidate for zt2. This finding was supported by qPCR analysis and further validated in different genetic backgrounds. Accordingly, VfTT8 was downregulated in white flowered types while showing high levels of expression in wild genotypes. Our results provide new insights on the regulatory mechanisms of tannin biosynthesis in faba bean and will facilitate the development of an ultimate zt2 diagnostic marker for the fast generation of new value-added cultivars free of tannins and with improved nutritional value.

Effects of faba bean extrusion and phytase supplementation on performance, phosphorus and nitrogen retention, and gut microbiota activity in broilers

BACKGROUND

Faba bean (FB) can be used in poultry diets as a protein source alternative to soybean meal. This study evaluated the effect of extrusion of low-tannin FB and phytase supplementation on performance, phosphorus (P) and nitrogen (N) retention, and gut microbiota activity in broiler chickens. Raw or extruded FB meal was included in broiler diet at 300 g kg^-1 . The experimental treatments additionally differed in nutrient level (adequate, or calcium, P, and protein reduced) and phytase supplementation.

RESULTS

Broiler performance was not affected by the dietary treatments. Extrusion and a reduced nutrient content did not affect P and N retention coefficients, but they increased when the reduced diets were supplemented with phytase. In the ileal digesta, FB extrusion increased the activities of bacterial α- and β-glucosidase, β-galactosidase, and β-glucuronidase, but acetate and total short-chain fatty acids (SCFAs) concentrations were higher only in birds fed extruded FB supplemented with phytase. In the cecal digesta, FB extrusion increased the activities of bacterial α- and β-glucosidase, α-galactosidase and β-glucuronidase, and phytase supplementation decreased β-glucosidase and β-glucuronidase activities, but acetate, butyrate and valerate and total SCFA concentrations were lower in birds fed extruded FB.

CONCLUSION

Good performance of broilers could be obtained using diets containing 300 g kg^-1 raw FB. The extrusion process does not improve FB nutritive value and may negatively affect the activity of cecal microbiota. Phytase supplementation allows lowering calcium, inorganic P, and protein level in diets with FB, and reduces P and N excreted in droppings, with a positive effect on the environment. © 2020 Society of Chemical Industry.

Do Faba Bean Genotypes Carrying Different Zero-Tannin Genes (zt1 and zt2) Differ in Phenolic Profiles?

Faba bean is a cool season grain legume that produces seeds with a high protein content. Seed coat tannins limit its use in food and feed. A low-tannin phenotype is controlled by either of two unlinked recessive genes zt1 and zt2. Liquid chromatography-mass spectrometry was used to characterize phenolic profiles of seed coat and flower tissue of three faba bean genotypes: CDC Snowdrop (zt1 gene), Disco/2 (zt2 gene), and ILB 938/2 (tannin-containing). For both tissues, clear differences in phenolic profiles of ILB 938/2 were observed in comparison to both low-tannin lines. Although seed coat phenolic profiles of zt1 and zt2 genotypes were similar, distinct differences were evident in flower tissue, suggesting that the gene action results in some different end products of the phenolic biosynthetic pathway. These distinctive compounds could be used as biochemical markers to distinguish between low-tannin phenotypes.

Host plant nutrient contents influence nutrient contents in Bradysia cellarum and Bradysia impatiens

The chive maggot Bradysia cellarum and the fungus gnat B. impatiens are two primary root pests of plants, which can coexist on the same host plants and are the devastating pests on liliaceous crops and edible fungi. Their growth and development are affected by the nutrient contents of their host plants. In this study, we assessed the effects of different host plant nutrients on the nutrient contents of these two Bradysia species. The nutrients of the chive (Allium tuberosum Rottl. ex Spreng.), board bean (Vicia faba L.), lettuce (Lactuca sativa L. var. ramosa Hort.), cabbage (Brassica oleracea L.), wild cabbage (Brassica oleracea var. capitata rubra) and pepper (Capsicum annuum L.) roots were determined, and their effect on nutrient content of the two Bradysia species after feeding on the host plant for three continuous generations were evaluated. The results show that chive and B-bean contained higher levels of protein, free amino acid, soluble sugar and starch than others. As a result, the soluble sugar, fat and protein contents were significantly higher in both Bradysia species reared on chive and B-bean than on cabbage, lettuce, W-cabbage and pepper, suggesting nutritional preference of these insects. Based on our results, we concluded that the two Bradysia species displayed nutrient preference toward chive and B-bean, which provides a reference for understanding their host plant range and for control of the insect species via field crop rotations.

Sodium nitroprusside (SNP) improves tolerance to arsenic (As) toxicity in Vicia faba through the modifications of biochemical attributes, antioxidants, ascorbate-glutathione cycle and glyoxalase cycle

The present study was conducted to evaluate the effect of arsenic (As) toxicity and the mitigating role of nitric oxide (NO) donor sodium nitroprusside (SNP) on Vicia faba. Arsenics stress decreased the growth and biomass yield, and photosynthetic pigments, but it enhanced As accumulation. Supplementation of NO enhanced the afore-mentioned parameters except As accumulation which decreased in both shoot and root. Supplementation of NO enhanced the shoot tolerance index (Shoot TI%), root tolerance index (Root TI%) but it declined the As translocation factor (TF). Application of NO alleviated the As-induced decline in net assimilation rate, stomatal conductance, transpiration and leaf relative water content. The levels of proline and glycine betaine (GB) further increased due to NO application, whereas malondialdehyde (MDA), hydrogen peroxide (H₂O₂), electrolyte leakage (EL) and methylglyoxal (MG) declined considerably. Activities of enzymatic antioxidants such as superoxide dismutase (SOD) and catalase (CAT) increased under As stress. Supplementation of NO up-regulated the enzymes involved in Asc-Glu cycle and glyoxalase cycle under As toxicity. Another experiment was setup to authenticate whether NO was certainly able to alleviate As toxicity. For this purpose, the NO scavenger [2-(4-carboxy-2 phenyl)-4,4,5,5-tertamethylimidazoline-1-oxyl-3-oxide (cPTIO)] was added to As and NO supplemented plants. Addition of cPTIO to NO supplemented As-treated plants showed the same effect when As alone was supplied to plants. In conclusion, addition of NO to the growth medium maintained the plant performance under As toxicity through modulation of physio-biochemical attributes, antioxidant enzymes, and the Asc-Glu and glyoxalase systems.

Using advanced vibrational molecular spectroscopy (ATR-Ft/IRS and synchrotron SR-IMS) to study an interaction between protein molecular structure from biodegradation residues and nutritional properties of cool-climate adapted faba bean seeds

The objective of this study was to use advanced vibrational molecular spectroscopy (ATR-Ft/IRS) to study an interaction between legume protein molecular structure from biodegradation residues and nutritional properties of newly developed genotypes of cool-climate adapted faba bean seed with low and normal tannin levels grown in western Canada. Protein molecular structures including amide I, II areas and peak heights, α-helix and β-sheet peak heights in rumen biodegradation residues were determined by using attenuated total reflectance Fourier transform infrared molecular spectroscopy (ATR-FTIR). The nutritional properties were determined which included chemical and nutrient profiles, in situ rumen degradation kinetics, rumen protein degradation, and intestinal protein digestion in the newly developed genotypes of faba bean seeds with low and normal tannin levels. The results showed that the spectral intensity of faba bean varieties with a normal tannin level in rumen biodegradation residues was greater (P < 0.05) than that with a low tannin level. The spectral intensity of amide I, II areas and peak heights, α-helix and β-sheet peak heights in all genotypes (except the variety of Snowdrop) in biodegradation residuals of faba bean seeds had a unique pattern with increasing first and then decreasing with the increasing of rumen incubation time. The molecular structures of protein (α-helix, ratio of α-helix to β-sheet height and amide I to II area, R² > 0.6) were associated with in situ degradation kinetics - soluble (S) and potential degradable fractions (D) and rumen protein degradation- bypass or undegraded protein (BCP or RUP). The molecular spectral parameters in the FTIR fingerprint region didn't form cluster among different genotypes in residual faba bean seeds in 12 h and 24 h incubation, which indicate they had similar protein molecular structures after incubation. In conclusion, there was an interaction between protein molecular structure from biodegradation residues and nutritional properties of newly developed cool-climate adapted faba bean seeds with normal and low level of tannin. The cool-climate adapted genotype had an impact on the protein molecular structure, and the protein utilization and metabolism were predictable from protein spectral molecular structures after rumen biodegradation with ATR-Ft/IRS spectroscopy.

A metabolomic, transcriptomic profiling, and mineral nutrient metabolism study of the phytotoxicity mechanism of uranium

Uranium (U) is a nonessential element that is readily adsorbed and retained in plant roots, causing root damage plants, rather than being translocated to other parts of the plant. The phytotoxicity mechanism of U is poorly understood. In this study, Vicia faba, a model plant for toxicological research, was selected as experimental material to investigate the phytotoxicity mechanism of U. In this study, the effects of U on the growth and development, methonome, transcriptome and mineral nutrient metabolism of V. faba were studied under different U treatments (0-25 μM) by integrating metabolomics, transcriptomic, and mineral nutrient metabolism analysis techniques. The results showed that U accumulation in roots and aboveground parts reached 164.34-927.90 μg/pot, and 0.028-0.119 μg/pot, respectively. U was mainly accumulated in the cell wall of roots, which damaged the root microstructure and inhibited root growth and development. In terms of mineral nutrient metabolism, U treatment (0-25 μM) led to changes in mineral metabolic profiles of seedlings. In total, 612 different metabolites were identified in nontargeted metabolomics, including 309 significantly upregulated metabolites and 303 significantly downregulated metabolites. Using RNA-seq, 4974 differentially expressed genes (DEGs) were identified under the high-concentration U treatment (25 μM), including 1654 genes significantly upregulated genes and 3320 genes significantly downregulated genes. Metabolic pathway analysis showed that a high concentration of U led to an imbalance of mineral nutrient metabolism in plants and changes in the metabolism and transcriptome pathway of plants, including alterations in the function of plasmodesmata and auxin signal transduction pathway. The latter finding may potentially explain the toxic effect of U on plant roots.

Nitric oxide is involved in nano-titanium dioxide-induced activation of antioxidant defense system and accumulation of osmolytes under water-deficit stress in Vicia faba L

Nano-titanium dioxide (nTiO₂) has been reported to improve tolerance of plants against different environmental stresses by modulating various physiological and biochemical processes. Nitric oxide (NO) has been shown to act as an important stress signaling molecule during plant responses to abiotic stresses. The present work was planned to investigate the involvement of endogenous NO in nTiO₂-induced activation of defense system of fava bean (Vicia faba L.) plants under water-deficit stress (WDS) conditions. Water-suffered plants showed increased concentration of hydrogen peroxide (H₂O₂) and superoxide (O₂^-) content coupled with increased electrolyte leakage and lipid peroxidation which adversely affected nitrate reductase (NR) activity, chlorophyll content and growth of the plants. However, application of 15 mg L^-1 nTiO₂ to stressed plants significantly induced NR activity and synthesis of NO which elevated enzymatic and non-enzymatic defense system of the stressed plants and suppressed the generation of H₂O₂ and O₂^- content, leakage of electrolytes, and lipid peroxidation. Application of nTiO₂, in association with NO, also enhanced the accumulation of osmolytes (proline and glycine betaine) that assisted the stressed plants in osmotic adjustment as witnessed by improved hydration level of the plants. Involvement of NO in nTiO₂-induced activation of defense system was confirmed with NO scavenger cPTIO [2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide] which caused recurrence of WDS.

Metabolomics of red-light-induced stomatal opening in Arabidopsis thaliana: Coupling with abscisic acid and jasmonic acid metabolism

Environmental stimuli-triggered stomatal movement is a key physiological process that regulates CO₂ uptake and water loss in plants. Stomata are defined by pairs of guard cells that perceive and transduce external signals, leading to cellular volume changes and consequent stomatal aperture change. Within the visible light spectrum, red light induces stomatal opening in intact leaves. However, there has been debate regarding the extent to which red-light-induced stomatal opening arises from direct guard cell sensing of red light versus indirect responses as a result of red light influences on mesophyll photosynthesis. Here we identify conditions that result in red-light-stimulated stomatal opening in isolated epidermal peels and enlargement of protoplasts, firmly establishing a direct guard cell response to red light. We then employ metabolomics workflows utilizing gas chromatography mass spectrometry and liquid chromatography mass spectrometry for metabolite profiling and identification of Arabidopsis guard cell metabolic signatures in response to red light in the absence of the mesophyll. We quantified 223 metabolites in Arabidopsis guard cells, with 104 found to be red light responsive. These red-light-modulated metabolites participate in the tricarboxylic acid cycle, carbon balance, phytohormone biosynthesis and redox homeostasis. We next analyzed selected Arabidopsis mutants, and discovered that stomatal opening response to red light is correlated with a decrease in guard cell abscisic acid content and an increase in jasmonic acid content. The red-light-modulated guard cell metabolome reported here provides fundamental information concerning autonomous red light signaling pathways in guard cells.

Protein coating composition targets nanoparticles to leaf stomata and trichomes

Plant nanobiotechnology has the potential to revolutionize agriculture. However, the lack of effective methods to deliver nanoparticles (NPs) to the precise locations in plants where they are needed impedes these technological innovations. Here, model gold nanoparticles (AuNP) were coated with citrate, bovine serum albumin (BSA) as a protein control, or LM6-M, an antibody with an affinity for functional groups unique to stomata on leaf surfaces to deliver the AuNPs to stomata. One-month-old Vicia faba leaves were exposed via drop deposition to aqueous suspensions of LM6-M-coated AuNPs and allowed to air dry. After rinsing, Au distribution on the leaf surface was investigated by enhanced dark-field microscopy and X-ray fluorescence mapping. While citrate-coated AuNPs randomly covered the plant leaves, LM6M-AuNPs strongly adhered to the stomata and remained on the leaf surface after rinsing, and BSA-AuNPs specifically targeted trichome hairs. To the authors' knowledge, this is the first report of active targeting of live leaf structures using NPs coated with molecular recognition molecules. This proof-of-concept study provides a strategy for future targeted nanopesticide delivery research.

Comprehensive transcriptome analysis of faba bean in response to vernalization

This study unravels the transcriptional response of a highly productive faba bean cultivar under vernalization treatment. Faba bean (Vicia faba L.) is a member of the Leguminosae family and an important food crop worldwide providing valuable nutrients for humans. However, genome-wide studies and comprehensive sequencing resources of faba bean remain limited. Vernalization is crucial for enhanced yields in a number of winter-sown crops. However, the effects of vernalization on faba bean remain unknown. In this study, we generated a high-quality transcriptome assembly and functional annotation source for vernalized faba bean (Vicia faba L.) cv. Tongxian-2, a domesticated cultivar from southern China. A total of 369.9 million clean Illumina paired-end RNA-Seq reads were generated, and the transcriptome was assembled into 68,683 unigene sequences, with an average length of 1018 bp and an N50 of 1652 bp. Comprehensive functional annotation provided putative functional descriptions for more than 70% of the faba bean transcripts. We annotated a total of 1560 faba bean transcripts encoding transcription factors (TFs) belonging to 55 distinct TF families. The bHLH (168 transcripts), ERF (123 transcripts) and WRKY (105 transcripts) contained the largest number of TFs in response to vernalization. Genome-wide transcript changes comparing vernalized and unvernalized seedlings were investigated using bioinformatics approaches, which revealed a strong repression of photosynthesis and carbon metabolism, while genes participating in 'response to stress' were significantly induced. We also specifically identified vernalization-induced twenty-two 'pollen-pistil interaction' genes. A detailed functional annotation and expression profile analyses unveiled a number of protein kinases, which were specifically induced in vernalized seedlings. We also identified a total of 6852 simple sequence repeats (SSRs) in 6552 transcripts, representing a valuable genomic molecular marker resource for faba bean. In summary, this study provides new insights into the vernalization process in this economically valuable crop. The transcriptome data obtained provides us with a valuable candidate gene resource for future functional and molecular breeding studies. These data will contribute to the genome annotation for ensuing genome projects.

Impact of broad beans addition on rheological and thermal properties of wheat flour based sourdoughs

Broad bean flour is a valuable source of proteins and micronutrients and can efficiently balance the nutritional value of wheat flour. The aim of the study was to assess the impact of wheat flour substitution by native and germinated broad beans on the water related, thermal and rheological properties of the composite flours and sourdoughs. Regardless of the investigated flour, temperature increase resulted in significant decrease of water soluble index. Addition of broad bean to wheat flour affected the swelling power. Differential scanning calorimetry measurements on flours indicated two peaks at ∼70 °C assigned to starch gelatinization, and ∼100 °C attributed to amylose-lipids complexes disruption. The same thermal dependent events were highlighted through the rheometric temperature ramp test. Sourdoughs were further obtained out of the composite flours and dynamic rheometric analysis showed that fermentation improved flow resistance. Wheat substitution by broad bean flour increased sourdoughs consistency due to the higher protein content.

Comparative transcriptomics analysis of potassium uptake pathways mediated cesium accumulation differences and related molecular mechanisms in Brassica juncea and Vicia faba

To analyze the differences between high- and low-accumulation plants in cesium (Cs) uptake and its related mechanism, Brassica juncea (a hyperaccumulation plant for Cs) and Vicia faba (a low-accumulation plant for Cs) were selected as comparative experimental materials. The contributions to Cs uptake of a K-transporter-mediated high-affinity transport system and a K-channel-mediated low-affinity transport system in the two plants were compared and analyzed. The difference between the two plants in the mechanism of Cs uptake was further analyzed using transcription sequence technology. The results show that the transfer characteristics of Cs in the two plants had a similar distribution relationship with K. The contribution rate of the K-channel pathway to Cs uptake was 32.00% in the V. faba seedling roots, which was significantly higher than for B. juncea (9.81%) (P < 0.01); the contribution rate of the K-transporter pathway to Cs uptake of the B. juncea seedlings was 32.08%, which was significantly higher than that of the V. faba seedlings (17.13%)(P < 0.05). Other uptake pathways also mediated the uptake of Cs by roots in B. juncea and V. faba (contribution rate: 54.92-60.09% and 42.18-59.73%, respectively). The transcriptome sequencing results confirmed that Cs-induced treatment significantly inhibited the expression of the K-transporter protein and K-channel protein-related genes in the V. faba roots, but it had no significant effect on the expression of related genes in the B. juncea roots. Thus, one reason for the significant difference between the two plant in the accumulation of Cs is that Cs inhibited the expression of related transporter protein genes in the V. faba roots.

Comparative analyses of cuticular waxes on various organs of faba bean (Vicia faba L.)

Cuticular waxes cover the plant surface and serve as hydrophobic layer, exhibiting various wax profiles between plant species and plant organs. This paper reports comprehensive analysis of the waxes on organs exposed to air, including leaf, stem, pod pericarp, and petals (banner, wing and keel), and on seed coat enwrapped in pod pericarp of faba bean (Vicia faba). In total 7 classes of wax compounds were identified, including fatty acids, primary alcohols, alkyl esters, aldehydes, alkanes, cinnamyl alcohol esters, and alkylresorcinols. Overall, primary alcohols dominated the waxes on leaves and the seed coat enwrapped in pod pericarp, alkanes accumulated largely in stem and petals, whereas alkylresorcinols were observed in leaf, stem and pod pericarp. Organs exposed to air had higher coverage (>1.2 μg/cm²) than those on seed coat (<0.8 μg/cm²), and keel having the highest wax coverage. Meanwhile, the wax coverage on seed coat reduced during the seed development. The variations of wax coverages, compound class distributions and chain length profiles among organs suggested that wax depositions were associated with their ecophysiological functions, and the enzymes involved in wax biosynthesis also showed organ-specific.