Full-Length Transcriptome Sequencing Reveals the Impact of Cold Stress on Alternative Splicing in Quinoa

Quinoa is a cold-resistant and nutrient-rich crop. To decipher the cold stress response of quinoa, the full-length transcriptomes of the cold-resistant quinoa variety CRQ64 and the cold-sensitive quinoa variety CSQ5 were compared. We identified 55,389 novel isoforms and 6432 novel genes in these transcriptomes. Under cold stress, CRQ64 had more differentially expressed genes (DEGs) and differentially alternative splicing events compared to non-stress conditions than CSQ5. DEGs that were specifically present only in CRQ64 were significantly enriched in processes which contribute to osmoregulation and ROS homeostasis in plants, such as sucrose metabolism and phenylpropanoid biosynthesis. More genes with differential alternative splicing under cold stress were enriched in peroxidase functions in CRQ64. In total, 5988 transcription factors and 2956 long non-coding RNAs (LncRNAs) were detected in this dataset. Many of these had altered expression patterns under cold stress compared to non-stress conditions. Our transcriptome results demonstrate that CRQ64 undergoes a wider stress response than CSQ5 under cold stress. Our results improved the annotation of the quinoa genome and provide new insight into the mechanisms of cold resistance in quinoa.

Changes in Quinoa Seed Fatty Acid Profile Under Heat Stress Field Conditions

The nutritional quality of quinoa is often related to the high protein content of their seeds. However, and despite not being an oilseed crop, the oil composition of quinoa seeds is remarkable due to its profile, which shows a high proportion of polyunsaturated fatty acids (PUFAs), particularly in essential fatty acids such as linoleic (ω-6) and α-linolenic (ω-3). In line with this, this study aimed at evaluating the effect of elevated temperatures on the oil composition of different quinoa cultivars grown in the field in two consecutive years (i.e., 2017 and 2018). In 2017, heat stress episodes resulted in a reduced oil content and lower quality linked to decreased ratios of oleic acid:linoleic acid, larger omega-6 (ω-6) to omega-3 (ω-3) ratios, and lower monounsaturated fatty acid (MUFA) and higher PUFA contents. Furthermore, the correlations found between mineral nutrients such as phosphorous (P) and the contents of oleic and linoleic acids emphasize the possibility of optimizing oil quality by controlling fertilization. Overall, the results presented in this study show how the environmental and genetic factors and their interaction may impact oil quality in quinoa seeds.

Integrative Transcriptome and Metabolome Profiles Reveal Common and Unique Pathways Involved in Seed Initial Imbibition Under Artificial and Natural Salt Stresses During Germination of Halophyte Quinoa

Salt stress is a major environmental factor that seriously restricts quinoa seed germination. However, the key regulatory mechanisms underlying the effect of salt stress on the initial imbibition stage of quinoa seeds are unclear. In this study, dry seeds (0 h) and imbibed (8 h) seeds with 450 mM NaCl (artificial salt) and 100% brackish water of Yellow River Estuary (BW, natural salt) were used to assess the key salt responses based on germination, transcriptome, and metabolome analyses. The results indicated that the capacity of germinating seeds to withstand these two salt stresses was similar due to the similarities in the germination percentage, germination index, mean germination time, and germination phenotypes. Combined omics analyses revealed that the common and unique pathways were induced by NaCl and BW. Starch and sucrose metabolism were the only commonly enriched pathways in which the genes were significantly changed. Additionally, amino sugar and nucleotide sugar metabolism, and ascorbate and aldarate metabolism were preferably enriched in the NaCl group. However, glutathione metabolism tended to enrich in the BW group where glutathione peroxidase, peroxiredoxin 6, and glutathione S-transferase were significantly regulated. These findings suggest that the candidates involved in carbohydrate metabolism and antioxidant defense can regulate the salt responses of seed initial imbibition, which provide valuable insights into the molecular mechanisms underlying the effect of artificial and natural salt stresses.

Characterization of Saponins from Differently Colored Quinoa Cultivars and Their In Vitro Gastrointestinal Digestion and Fermentation Properties

Quinoa contains rich saponins, which are removed during processing and cause ecological waste. We extracted saponins from quinoa (SEQ) in black, white, and red cultivars and compared their composition by spectrophotometric assay and high-performance liquid chromatography analysis combined with acid hydrolysis. The digestion and fermentation properties of SEQ were investigated using an in vitro model. Our results showed that acid hydrolysis released sapogenins, mainly phytolaccagenin (PA), hederagenin (HD), and oleanolic acid from SEQ. Varying from SEQ in red, SEQ in black and white had a similar composition and content of sapogenins. Gastrointestinal digestion did not release sapogenins from SEQ but reduced the antioxidant activity of SEQ. Gut microbiota from human feces released PA and HD from SEQ. Reciprocally, SEQ in black significantly increased the growth of Lactobacillus spp. and Bifidobacterium spp., while reducing the growth of Shigella spp. The present study provides guidance for further investigation about the bioactivities of saponins from quinoa.

Bound Polyphenols from Red Quinoa Prevailed over Free Polyphenols in Reducing Postprandial Blood Glucose Rises by Inhibiting α-Glucosidase Activity and Starch Digestion

Inhibiting α-glucosidase activity is important in controlling postprandial hyperglycemia and, thus, helping to manage type-2 diabetes mellitus (T2DM). In the present study, free polyphenols (FPE) and bound polyphenols (BPE) were extracted from red quinoa and their inhibitory effects on α-glucosidase and postprandial glucose, as well as related mechanisms, were investigated. HPLC-MS analysis showed that the components of FPE and BPE were different. FPE was mainly composed of hydroxybenzoic acid and its derivatives, while BPE was mainly composed of ferulic acid and its derivatives. BPE exhibited stronger DPPH and ABTS antioxidant activities, and had a lower IC50 (10.295 mg/mL) value in inhibiting α-glucosidase activity. The inhibition kinetic mode analysis revealed that FPE and BPE inhibited α-glucosidase in a non-competitive mode and an uncompetitive mode, respectively. Furthermore, compared to FPE, BPE delayed starch digestion more effectively. BPE at 50 mg/kg reduced postprandial glucose increases comparably to acarbose at 20 mg/kg in ICR mice. These results could provide perspectives on the potential of BPE from red quinoa, as a functional food, to inhibit α-glucosidase activity, delay postprandial glucose increases and manage T2DM.

Heat stress changes mineral nutrient concentrations in Chenopodium quinoa seed

Quinoa is a popular seed crop, often consumed for its high nutritional quality. We studied how heat stress in the roots or the shoots of quinoa plants affected the concentrations of 20 elements (aluminum, arsenic, boron, calcium, cadmium, cobalt, copper, iron, potassium, magnesium, manganese, molybdenum, sodium, nickel, phosphorous, rubidium, sulfur, selenium, strontium, and zinc) in quinoa seed. Elemental concentrations in quinoa seed were significantly changed after an 11-day heat treatment during anthesis. The type of panicle (main, secondary, and tertiary) sampled and the type of heat treatment (root only, shoot only, or whole plants) significantly affected elemental profiles in quinoa seed. Plants were also divided into five sections from top to bottom to assess the effect of panicle position on seed elemental profiles. Plant section had an effect on the concentrations of arsenic, iron, and sodium under control conditions and on copper with heat treatment. Overall, the time of panicle development in relation to the time of heat exposure had the largest effect on seed elemental concentrations. Interestingly, the quinoa plants were exposed to heat only during anthesis of the main panicle, but the elemental concentrations of seeds produced after heat treatment ended were still significantly changed, indicating that heat stress has long-lasting effects on quinoa plants. These findings demonstrate how the nutritional quality of quinoa seeds can be changed significantly even by relatively short heat spells.

Nutritional Composition and Bioactive Components in Quinoa (Chenopodium quinoa Willd.) Greens: A Review

Quinoa (Chenopodium quinoa Willd.) is a nutrient-rich grain native to South America and eaten worldwide as a healthy food, sometimes even referred to as a ”superfood”. Like quinoa grains, quinoa greens (green leaves, sprouts, and microgreens) are also rich in nutrients and have health promoting properties such as being antimicrobial, anticancer, antidiabetic, antioxidant, antiobesity, and cardio-beneficial. Quinoa greens are gluten-free and provide an excellent source of protein, amino acids, essential minerals, and omega-3 fatty acids. Quinoa greens represent a promising value-added vegetable that could resolve malnutrition problems and contribute to food and nutritional security. The greens can be grown year-round (in the field, high tunnel, and greenhouse) and have short growth durations. In addition, quinoa is salt-, drought-, and cold-tolerant and requires little fertilizer and water to grow. Nevertheless, consumption of quinoa greens as leafy vegetables is uncommon. To date, only a few researchers have investigated the nutritional properties, phytochemical composition, and human health benefits of quinoa greens. We undertook a comprehensive review of the literature on quinoa greens to explore their nutritional and functional significance to human health and to bring awareness to their use in human diets.

Morphological and Physiological Traits Associated with Yield under Reduced Irrigation in Chilean Coastal Lowland Quinoa

Quinoa (Chenopodium quinoa Willd.) is a genetically diverse crop that has gained popularity in recent years due to its high nutritional content and ability to tolerate abiotic stresses such as salinity and drought. Varieties from the coastal lowland ecotype are of particular interest due to their insensitivity to photoperiod and their potential to be cultivated in higher latitudes. We performed a field experiment in the southern Atacama Desert in Chile to investigate the responses to reduced irrigation of nine previously selected coastal lowland self-pollinated (CLS) lines and the commercial cultivar Regalona. We found that several lines exhibited a yield and seed size superior to Regalona, also under reduced irrigation. Plant productivity data were analyzed together with morphological and physiological traits measured at the visible inflorescence stage to estimate the contribution of these traits to differences between the CLS lines and Regalona under full and reduced irrigation. We applied proximal sensing methods and found that thermal imaging provided a promising means to estimate variation in plant water use relating to yield, whereas hyperspectral imaging separated lines in a different way, potentially related to photosynthesis as well as water use.

Quinoa Soluble Fiber and Quercetin Alter the Composition of the Gut Microbiome and Improve Brush Border Membrane Morphology In Vivo (Gallus gallus)

Quinoa (Chenopodium quinoa Willd.), a gluten-free pseudo-cereal, has gained popularity over the last decade due to its high nutritional value. Quinoa is a rich source of proteins, carbohydrates, fibers, tocopherols (Vitamin E), unsaturated fatty acids and a wide range of polyphenols. The study used Gallus gallus intra-amniotic feeding, a clinically validated method, to assess the effects of quinoa soluble fiber (QSF) and quercetin 3-glucoside (Q3G) versus control. Quercetin is a pharmacologically active polyphenol found in quinoa. Six groups (no injection, 18 Ω H2O, 5% inulin, 1% Q3G, 5% QSF, 1% Q3G + 5% QSF) were assessed for their effect on the brush border membrane (BBM) functionality, intestinal morphology and cecal bacterial populations. Our results showed a significant (p < 0.05) improvement in BBM morphology, particularly goblet and Paneth cell numbers, in the group administered with quinoa and quercetin. However, there were no significant changes seen in the expression of the genes assessed both in the duodenum and liver between any of the treatment groups. Furthermore, fibrous quinoa increased the concentration of probiotic L. plantarum populations compared to the control (H2O). In conclusion, quercetin and quinoa fiber consumption has the potential to improve intestinal morphology and modulate the microbiome.

Biogeographical Patterns of Herbivore Arthropods Associated with Chenopodium quinoa Grown along the Latitudinal Gradient of Chile

Identifying the particular guilds of herbivore arthropods that affect the production of crops is key to developing sustainable pest-management strategies; however, there is incomplete information about the identity of herbivore arthropods that could potentially damage the production of both highland and lowland quinoa landraces grown in Chile. By both reviewing the literature and conducting field collections across a large latitudinal gradient, we generated an updated list of 43 herbivore arthropods associated with quinoa production in Chile. In general, most species are polyphagous feeders, and only seven are specialists. The number and identity of species varied in relation with the latitude, such that four distinctive assemblages of herbivores were identified, each containing 32, 27, 34, and 22 species between latitudes 18-26, 26-32, 32-40, and 40-44° S, respectively. The most northern production area (18-26° S) is affected by nine unique species, including the major quinoa pest Eurysacca quinoae Povolný (Lepidoptera: Gelechiidae). Similarly, the central area (32-40° S) contains four unique species, including Eurysacca media Povolný (Lepidoptera: Gelechiidae) and Orthotylus flavosparsus (Sahlberg) (Hemiptera: Miridae). The particular species assemblages described here will help further development of local pest-management practices.

Quinoa (Chenopodium quinoa Willd.): Genetic Diversity According to ISSR and SCoT Markers, Relative Gene Expression, and Morpho-Physiological Variation under Salinity Stress

Quinoa (Chenopodium quinoa Willd.) is a halophytic crop that can withstand a variety of abiotic stresses, including salt. The present research examined the mechanisms of salt tolerance in five different quinoa genotypes at four different salinity levels (control (60), 80, 120, and 160 mM NaCl). ISSR and SCoT analysis revealed high polymorphism percentages of 90.91% and 85.26%, respectively. Furthermore, ISSR 1 and SCoT 7 attained the greatest number of polymorphic amplicons (27 and 26), respectively. Notably, LINE-6 and M-28 genotypes demonstrated the greatest number of unique positive and negative amplicons (50 and 42) generated from ISSR and SCoT, respectively. Protein pattern analysis detected 11 bands with a polymorphism percentage 27.27% among the quinoa genotypes, with three unique bands distinguishable for the M-28 genotype. Similarity correlation indicated that the highest similarity was between S-10 and Regeolone-3 (0.657), while the lowest similarity was between M-28 and LINE-6 (0.44). Significant variations existed among the studied salinity treatments, genotypes, and the interactions between them. The highest and lowest values for all the studied morpho-physiological and biochemical traits were recorded at 60 and 160 mM NaCl concentrations, respectively, except for the Na and proline contents, which exhibited the opposite relationship. The M-28 genotype demonstrated the highest values for all studied characteristics, while the LINE-6 genotype represented the lowest in both seasons. On the other hand, mRNA transcript levels for CqSOS1 did not exhibit differential expression in roots and leaf tissues, while the expression of CqNHX1 was upregulated more in both tissues for the M-28 genotype than for the LINE-6 genotype, and its maximum induction was seen in the leaves. Overall, the genotypes M-28 and LINE-6 were identified as the most and least salinity-tolerant, respectively.

Effect of Different Black Quinoa Fractions (Seed, Flour and Wet-Milling Coproducts) upon Quality of Meat Patties during Freezing Storage

In this study, the quality of meat patty samples containing different black quinoa fractions (seed, flour and wet-milling coproducts) was evaluated during freezing preservation. Composition, physicochemical parameters (aw, pH, colour and texture), cooking properties, lipid oxidation and sensory characteristic were studied in four batches (control and 8% concentration of quinoa seed, flour and wet-milling coproducts added) at 30, 60 and 90 days of freezing (−20 ± 1 °C). Different black quinoa fraction addition affected (p < 0.05) physiochemical properties, improved cooking properties and reduced lipid oxidations during freezing storage. Batches with flour and wet-milling coproducts added were the most stable for texture parameters and lipid oxidation during freezing. The results obtained showed that quinoa wet-milling co-products could be considered a valuable sustainable and organic food ingredient, maintaining nutritional and global qualities of the fresh meat product. In addition, freezing storage is an effective way to prolong the shelf life of patties with different black quinoa fractions, added without affecting quality.

Effect of Heat-Moisture Treatments on Digestibility and Physicochemical Property of Whole Quinoa Flour

The starch digestion processing of whole grain foods is associated with its health benefits in improving insulin resistance. This study modified the digestibility of whole quinoa flour (WQ) via heat-moisture treatment (HMT), HMT combined with pullulanase (HMT+P), HMT combined with microwave (HMT+M), and HMT combined with citric acids (HMT+A), respectively. Results showed that all the treatments significantly increased (p < 0.05) the total dietary fiber (TDF) content, amylose content, and resistant starch (RS) content, however, significantly decreased (p < 0.05) the amylopectin content and rapidly digestible starch (RDS) content of WQ. HMT+P brought the highest TDF content (15.3%), amylose content (31.24%), and RS content (15.71%), and the lowest amylopecyin content (30.02%) and RDS content (23.65%). HMT+M brought the highest slowly digestible starch (SDS) content (25.09%). The estimated glycemic index (eGI) was respectively reduced from 74.36 to 70.59, 65.87, 69.79, and 69.12 by HMT, HMT+P, HMT+M, and HMT+A. Moreover, a significant and consistent reduction in the heat enthalpy (ΔH) of WQ was observed (p < 0.05), after four treatments. All these effects were caused by changes in the starch structure, as evidenced by the observed conjunction of protein and starch by a confocal laser scanning microscope (CLSM), the decrease in relative crystallinity, and transformation of starch crystal.

Textural and sensory characteristics of sugar-free biscuit formulated with quinoa flour, isomalt, and maltodextrin

A low-calorie biscuit formulation containing quinoa flour (cultivars TTKK), isomalt, and maltodextrin was optimized using response surface methodology. Optimized samples were evaluated in terms of total phenolic compounds (TPC), sensory properties, and nutritional value while samples containing only wheat flour (Pishgam var.) and sucrose were used as control. Morphology of isolated starch from quinoa was also investigated. The results showed that with increasing amounts of quinoa, isomalt, and maltodextrin ΔE and Browning index increased, whereas hardness and L values decreased. The formulation containing 25% quinoa flour, 3.5% maltodextrin, and 10% isomalt was found to be optimal with an overall desirability value of 0.95. The sensory evaluation showed that replacement of wheat flour with 25 g/100 g quinoa flour in biscuits was acceptable. TPC of the optimal biscuit (1,180.34 ± 0.02 μg GAE/g) was higher than that of the control sample (729.95 ± 0.007 μg GAE/g). In addition, the optimized biscuit had more protein (8.36 ± 0.035%) and dietary fiber (2.14 ± 0.035%) content compared with the control sample (7.01 ± 0.007% and 1.66 ± 0.028%, respectively). The consumption of 100 g of optimized quinoa biscuits supplies the daily requirement of Fe, Mg, Ca, and Zn at 2.43%, 44.81%, 19.46% and 1.12%, respectively.

Genome-Wide Transcriptomic and Proteomic Exploration of Molecular Regulations in Quinoa Responses to Ethylene and Salt Stress

Quinoa (Chenopodiumquinoa Willd.), originated from the Andean region of South America, shows more significant salt tolerance than other crops. To reveal how the plant hormone ethylene is involved in the quinoa responses to salt stress, 4-week-old quinoa seedlings of 'NL-6' treated with water, sodium chloride (NaCl), and NaCl with ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) were collected and analyzed by transcriptional sequencing and tandem mass tag-based (TMT) quantitative proteomics. A total of 9672 proteins and 60,602 genes was identified. Among them, the genes encoding glutathione S-transferase (GST), peroxidase (POD), phosphate transporter (PT), glucan endonuclease (GLU), beta-galactosidase (BGAL), cellulose synthase (CES), trichome birefringence-like protein (TBL), glycine-rich cell wall structural protein (GRP), glucosyltransferase (GT), GDSL esterase/lipase (GELP), cytochrome P450 (CYP), and jasmonate-induced protein (JIP) were significantly differentially expressed. Further analysis suggested that the genes may mediate through osmotic adjustment, cell wall organization, reactive oxygen species (ROS) scavenging, and plant hormone signaling to take a part in the regulation of quinoa responses to ethylene and salt stress. Our results provide a strong foundation for exploration of the molecular mechanisms of quinoa responses to ethylene and salt stress.

Low Acrylamide Flatbreads from Colored Corn and Other Flours

Dietary acrylamide formed during baking and frying of plant-based foods such as bread and other cereal products, coffee, fried potatoes, and olives is reported to induce genotoxic, carcinogenic, neurotoxic, and antifertility properties in vivo, suggesting the need to keep the acrylamide content low with respect to widely consumed heat-processed food including flatbreads. Due to the fact that pigmented corn flours contain biologically active and health-promoting phenolic and anthocyanin compounds, the objective of this study was to potentially define beneficial properties of flatbread by evaluating the acrylamide content determined by high-performance liquid chromatography/mass spectrometry (HPLC/MS) with a detection limit of 1.8 µg/kg and proximate composition by standard methods of six experimental flatbreads made from two white, two blue, one red, and one yellow corn flours obtained by milling commercial seeds. Acrylamide content was also determined in experimental flatbreads made from combinations in quinoa flour, wheat flour, and peanut meal with added broccoli or beet vegetables and of commercial flatbreads including tortillas and wraps. Proximate analysis of flatbreads showed significant differences in protein and fat but not in carbohydrate, mineral, and water content. The acrylamide content of 16 evaluated flatbreads ranged from 0 to 49.1 µg/kg, suggesting that these flatbreads have the potential to serve as low-acrylamide functional foods. The dietary significance of the results is discussed.

Genotype-Dependent Variation of Nutritional Quality-Related Traits in Quinoa Seeds

Exploiting the relationship between the nutritional properties of seeds and the genetic background constitutes an essential analysis, which contributes to broadening our knowledge regarding the control of the nutritional quality of seeds or any other edible plant structure. This is an important aspect when aiming at improving the nutritional characteristics of crops, including those of Chenopodium quinoa Willd. (quinoa), which has the potential to contribute to food security worldwide. Previous works have already described changes in the nutritional properties of quinoa seeds due to the influence of the environment, the genotype, or their interaction. However, there is an important limitation in the analyses carried out, including the outcomes that can be translated into agronomical practices and their effect on seed quality. In the present study, several seed nutritional-related parameters were analyzed in 15 quinoa cultivars grown in a particular environmental context. Important agronomical and nutritional differences were found among cultivars, such as variations in mineral or protein contents and seed viability. More importantly, our analyses revealed key correlations between seed quality-related traits in some cultivars, including those that relate yield and antioxidants or yield and the germination rate. These results highlight the importance of considering the genotypic variation in quinoa when selecting improved quinoa varieties with the best nutritional characteristics for new cultivation environments.

Quinoa sourdough-based biscuits with high antioxidant activity fermented with autochthonous lactic acid bacteria

AIMS

To evaluate the capacity of autochthonous lactic acid bacteria (LAB) (43) from Andean grains to increase the antioxidant activity (AOA) and total phenolic compounds (TPCs) in quinoa sourdough to select best performing strains to be used as starter cultures in the elaboration of biscuits.

METHODS AND RESULTS

Microbial growth (CFU per g) and pH were evaluated during quinoa dough fermentation. Counts were increased in a range of 0.61-2.97 log CFU per g and pH values between 3.95 and 4.54 were determined after 24 h at 30°C of fermentation. Methanolic (ME) and aqueous (AE) extracts were obtained at the end of fermentation, and free radical scavenging capacity was performed by the DPPH and ABTS methods. ME was selected for further analysis using other methods and TPC quantification. Principal component analysis showed the highest scores of growth, acidification capacity, AOA and TPC for the strains Lc. mesenteroides subsp. mesenteroides CRL 2131 and L. plantarum CRL 1964 and CRL 1973. AOA and TPC in biscuits made with sourdough from these LAB were higher than the acidified and uninoculated controls.

CONCLUSIONS

Autochthonous LAB strains (3) increased the AOA of quinoa-based biscuits.

SIGNIFICANCE AND IMPACT OF THE STUDY

Quinoa sourdough obtained with selected LAB is suitable as an ingredient for bakery foods with improved antioxidant status.

Anti-Fungal Hevein-like Peptides Biosynthesized from Quinoa Cleavable Hololectins

Chitin-binding hevein-like peptides (CB-HLPs) belong to a family of cysteine-rich peptides that play important roles in plant stress and defense mechanisms. CB-HLPs are ribosomally synthesized peptides that are known to be bioprocessed from the following two types of three-domain CB-HLP precursor architectures: cargo-carrying and non-cargo-carrying. Here, we report the identification and characterization of chenotides biosynthesized from the third type of precursors, which are cleavable hololectins of the quinoa (Chenopodium quinoa) family. Chenotides are 6-Cys-CB-HLPs of 29–31 amino acids, which have a third type of precursor architecture that encompasses a canonical chitin-binding domain that is involved in chitin binding and anti-fungal activities. Microbroth dilution assays and microscopic analyses showed that chenotides are effective against phyto-pathogenic fungi in the micromolar range. Structure determination revealed that chenotides are cystine knotted and highly compact, which could confer resistance against heat and proteolytic degradation. Importantly, chenotides are connected by a novel 18-residue Gly/Ala-rich linker that is a target for bioprocessing by cathepsin-like endopeptidases. Taken together, our findings reveal that chenotides are a new family of CB-HLPs from quinoa that are synthesized as a single multi-modular unit and bioprocessed to yield individual mature CB-HLPs. Importantly, such precursors constitute a new family of cleavable hololectins. This unusual feature could increase the biosynthetic efficiency of anti-fungal CB-HLPs, to provide an evolutionary advantage for plant survival and reproduction.

Phytopathological Threats Associated with Quinoa (Chenopodium quinoa Willd.) Cultivation and Seed Production in an Area of Central Italy

In 2017, in a new Chenopodium quinoa cultivation area (Central Italy), emergence failures of the Titicaca, Rio Bamba, and Real varieties, whose seeds were obtained the previous year (2016) in the same location, were observed. Moreover, leaf disease symptoms on the Regalona variety, whose seeds came from Chile, were detected. Visual and microscopic analyses showed the presence of browning/necrotic symptoms on the seeds of the three varieties whose emergence in the field had failed. In addition, their in vitro germination rates were strongly compromised. Fusarium spp. was isolated with high incidence from Titicaca, Rio Bamba, and Real seeds. Among the detected Fusarium species, in the phylogenetic analysis, the dominant one clustered in the sub-clade Equiseti of the Fusarium incarnatum-equiseti (FIESC) species complex. Instead, the pathogen associated with Regalona leaf symptoms was identified, by morphological and molecular features, as Peronospora variabilis, the causal agents of downy mildew. This is the first report of both P. variabilis and F. equiseti on C. quinoa in Italy. Species-specific primers also detected P. variabilis in Regalona seeds. These results underline the importance of pathogen monitoring in new quinoa distribution areas, as well as of healthy seed production and import for successful cultivation.

High-Resolution Analysis of Growth and Transpiration of Quinoa Under Saline Conditions

The Plantarray 3.0 phenotyping platform^® was used to monitor the growth and water use of the quinoa varieties Pasto and selRiobamba under salinity (0-300 mM NaCl). Salinity reduced the cumulative transpiration of both varieties by 60% at 200 mM NaCl and by 75 and 82% at 300 mM NaCl for selRiobamba and Pasto, respectively. Stomatal conductance was reduced by salinity, but at 200 mM NaCl Pasto showed a lower reduction (15%) than selRiobamba (35%), along with decreased specific leaf area. Diurnal changes in water use parameters indicate that under salt stress, daily transpiration in quinoa is less responsive to changes in light irradiance, and stomatal conductance is modulated to maximize CO₂ uptake and minimize water loss following the changes in VPD (vapor pressure deficit). These changes might contribute to the enhanced water use efficiency of both varieties under salt stress. The mechanistic crop model LINTUL was used to integrate physiological responses into the radiation use efficiency of the plants (RUE), which was more reduced in Pasto than selRiobamba under salinity. By the end of the experiment (eleven weeks after sowing, six weeks after stress), the growth of Pasto was significantly lower than selRiobamba, fresh biomass was 50 and 35% reduced at 200 mM and 70 and 50% reduced at 300 mM NaCl for Pasto and selRiobamba, respectively. We argue that contrasting water management strategies can at least partly explain the differences in salt tolerance between Pasto and selRiobamba. Pasto adopted a "conservative-growth" strategy, saving water at the expense of growth, while selRiobamba used an "acquisitive-growth" strategy, maximizing growth in spite of the stress. The implementation of high-resolution phenotyping could help to dissect these complex growth traits that might be novel breeding targets for abiotic stress tolerance.

Perspective: A Legal and Nutritional Perspective on the Introduction of Quinoa-Based Infant and Follow-on Formula in the EU

Infants are vulnerable consumers and highly depend on dietary proteins for growth and development during their first months of life. Infant formula (IF) and follow-on formula (FOF) have been developed to meet these requirements, although few protein sources are currently allowed to be used. At the same time, allergies to these available protein sources are becoming more frequent. There is thus a need to explore alternative protein sources for infant nutrition. One alternative could be quinoa, which is a pseudocereal that is naturally free from gluten and has a high protein content and quality. This review assessed the composition, nutritional properties, and applicability of quinoa proteins for IF and FOF as well as the legal framework for their use in the European Union (EU). The protein quality of isolated quinoa proteins (IQPs) is relatively high compared with other plant-based proteins like rice. Besides, during the protein isolation process, unfavorable compounds are mostly removed, ensuring that the final product can comply with the maximum residue concentrations allowed. Overall, IF and FOF are strictly regulated under the Foods for Specific Groups (FSG) Regulation (EU) No 609/2013 and more research is needed before the introduction of IQP in such products is considered, but this review shows it has several promising features that warrant further investigation.

Effect of Quinoa (Chenopodium quinoa Willd.) Starch and Seeds on the Physicochemical and Textural and Sensory Properties of Chicken Meatballs during Frozen Storage

The effects of starch (corn and quinoa) and quinoa seeds on chicken meatballs' physicochemical, textural, and sensory properties were investigated during frozen storage. The chicken meatballs were prepared with corn starch (CS), quinoa starch (QS), quinoa seeds (Q), and combinations of corn starch and quinoa seeds (CS-Q), and quinoa starch and quinoa seeds (QS-Q), which were subjected to five freeze-thaw (F-T) cycles of temperature fluctuation conditions during frozen storage. Regardless of the type used (CS or QS), adding starch resulted in fewer cooking, drip, and reheating losses in chicken meatballs during frozen storage. The values of the hardness, gumminess, and chewiness of chicken meatballs with CS or QS were half those of chicken meatballs without starch, indicating that the addition of starch inhibited the change in the meatballs' texture. The total volatile basic nitrogen (TVB-N) and thiobarbituric acid reactive substance (TBARS) values were progressive but did not dynamically increase during five F-T cycles. Chicken meatballs containing CS-Q or QS-Q showed significantly lower TBARS values than those with CS, QS, or Q after five F-T cycles. Adding quinoa seeds significantly increased the antioxidant activity and the chewiness of meatballs (p < 0.05) compared with starch only. The addition of the combination of QS-Q to chicken meatballs increased the values of taste, texture, and overall acceptability, indicating that quinoa starch and seeds may be introduced as premium ingredients to frozen meat products.

The genotype-dependent phenotypic landscape of quinoa in salt tolerance and key growth traits

Cultivation of quinoa (Chenopodium quinoa), an annual pseudocereal crop that originated in the Andes, is spreading globally. Because quinoa is highly nutritious and resistant to multiple abiotic stresses, it is emerging as a valuable crop to provide food and nutrition security worldwide. However, molecular analyses have been hindered by the genetic heterogeneity resulting from partial outcrossing. In this study, we generated 136 inbred quinoa lines as a basis for the molecular identification and characterization of gene functions in quinoa through genotyping and phenotyping. Following genotyping-by-sequencing analysis of the inbred lines, we selected 5,753 single-nucleotide polymorphisms (SNPs) in the quinoa genome. Based on these SNPs, we show that our quinoa inbred lines fall into three genetic sub-populations. Moreover, we measured phenotypes, such as salt tolerance and key growth traits in the inbred quinoa lines and generated a heatmap that provides a succinct overview of the genotype–phenotype relationship between inbred quinoa lines. We also demonstrate that, in contrast to northern highland lines, most lowland and southern highland lines can germinate even under high salinity conditions. These findings provide a basis for the molecular elucidation and genetic improvement of quinoa and improve our understanding of the evolutionary process underlying quinoa domestication.

Modelling and Optimization of Ultrasound-Assisted Extraction of Phenolic Compounds from Black Quinoa by Response Surface Methodology

Phenolic compounds are currently the most investigated class of functional components in quinoa. However, great variability in their content emerged, because of differences in sample intrinsic and extrinsic characteristics; processing-induced factors; as well as extraction procedures applied. This study aimed to optimize phenolic compound extraction conditions in black quinoa seeds by Response Surface Methodology. An ultrasound-assisted extraction was performed with two different mixtures; and the effect of time; temperature; and sample-to-solvent ratio on total phenolic content (TPC) was investigated. Data were fitted to a second-order polynomial model. Multiple regression analysis and analysis of variance were used to determine the fitness of the model and optimal conditions for TPC. Three-dimensional surface plots were generated from the mathematical models. TPC at optimal conditions was 280.25 ± 3.94 mg of Gallic Acid Equivalent (GAE) 100 g⁻¹ dm upon extraction with aqueous methanol/acetone, and 236.37 ± 5.26 mg GAE 100 g⁻¹ dm with aqueous ethanol mixture. The phenolic profile of extracts obtained at optimal conditions was also investigated by HPLC. The two extracting procedures did not show different specificities for phenolic compounds but differed in the extraction yield.