Shotgun proteomics profiling of chia seeds (Salvia hispanica L.) reveals genotypic differential responses to viability loss.

Introduction: Exposure to elevated temperatures and relative humidity expedites the seed aging process, finally leading to seed viability loss. In this context, certain proteins play a pivotal role in safeguarding the longevity of seeds. However, the seedproteomic response to loss viability in Salvia hispanica L., commonly known as chia, remains incompletely understood. Methods: This work explores the application of proteomics as a potent tool for uncovering molecular responses to viability loss caused by artificial aging in two chia genotypes, WN and MN. Results: By using a quantitative label-free proteomics analysis (LC-MS/MS), 1787 proteins wereidentified in chia seeds at a 95% confidence level, including storage proteins, heat shock proteins (HSPs), late embryogenesis abundant proteins (LEA),oleosins, reactive oxygen species (ROS)-related enzymes, and ribosomal proteins. A relatively low percentage of exclusive proteins were identified in viable and non-viable seeds. However, proteins exhibiting differential abundancebetween samples indicated variations in the genotype and physiological status. Specifically, the WN genotype showed 130 proteins with differential abundancecomparing viable and non-viable seeds, while MN displayed changes in the abundance of 174 proteins. While both showed a significant decrease in keyproteins responsible for maintaining seed functionality, longevity, and vigor withhigh-temperature and humidity conditions, such as LEA proteins or HSPs, ROS, and oleosins, distinct responses between genotypes were noted, particularly in ribosomal proteins that were accumulated in MN and diminished in WN seeds. Discussion: Overall, the results emphasize the importance of evaluating changes in proteins of viable and non-viable seeds as they offer valuable insights into the underlying biological mechanisms responsible for the maintenance of chia seed integrity throughout high-temperature and humidity exposure.

Evaluating Yield, Nutritional Quality, and Environmental Impact of Quinoa Straws across Mediterranean Water Environments.

Quinoa (Chenopodium quinoa Willd.) is a promising and versatile crop due to its remarkable adaptability to diverse environments and the exceptional nutritional value of its seeds. Nevertheless, despite the recent extensive research on quinoa seeds, the straw associated with this crop has received comparatively little attention. The valorisation of this by-product provides an opportunity to improve the overall outcomes of quinoa cultivation. In this work, three quinoa varieties were evaluated for two years (2019 and 2020) under three different Mediterranean water environments (irrigation, fresh rainfed, and hard rainfed), aiming to assess the straw yield and nutritional quality and to study the changes in the crop nutritional uptake associated with different water environmental conditions. The nutritional analysis included the quantification of the ash, crude protein, crude fat, minerals (P, K, Ca, Mg), and fibre (gross fibre (GF), acid detergent fibre (ADF), neutral detergent fibre (NDF), acid detergent lignin (ADL), hemicellulose, cellulose) contents. As the results reveal, most of the parameters evaluated were susceptible to change mainly with the water environment but also with the genotype (or their interaction), including the yield, crude protein, relative feed value (RFV), and mineral content, which generally decreased under water-limiting conditions. Moreover, a comparative analysis revealed that straw Ca, Mg, and K contents were generally higher than in seeds. Overall, this study demonstrates that quinoa straw quality is genotypic and environmentally dependent, and these factors should be considered when aiming at improving straw feed value for livestock nutrition.

Nutritional composition of quinoa leafy greens: An underutilized plant-based food with the potential of contributing to current dietary trends.

Quinoa (Chenopodium quinoa Willd.) leafy greens (QLGs) are plant-based foods of high nutritional value that have been scarcely studied. In this work, the nutritional and functional composition of three QLGs varieties was evaluated. A protein content higher than 35 g 100 g-1 dw with a well-balanced essential amino acid composition was found making them a good source of vegetable protein. In addition, elevated contents of dietary fibre and minerals, higher than those detected in quinoa seeds and other leafy vegetables, were found. The lipid profile showed higher contents of linoleic (C18:2, ω6) (20.2 %) and linolenic acids (C18:3, ω3) (52.8 %) with low ω6/ ω3 ratios (∼0.4/1). A total sugar content <1 g 100 g-1 dw was found for all varieties tested, lower than that obtained in seeds. The saponin content varied between 0.76 and 0.87 %. Also, high values of total phenolic compounds (969.8-1195.4 mg gallic acid 100 g-1), mainly hydroxycinnamic acids and flavonoids, and great antioxidant activities (7.64-8.90 g Trolox kg-1) were found. Multivariate analysis here used allowed us to classify the samples according to the quinoa variety evaluated, and the sequential stepwise multiple regression applied revealed that the PUFA and sucrose contents negatively influenced the protein content while the palmitic acid content affected positively this parameter. Overall, this study shows that QLGs are promising nutritious and functional plant-based foods supporting the necessity of promoting their cultivation, commercialization, and consumption.

Unveiling changes in rhizosphere-associated bacteria linked to the genotype and water stress in quinoa.

Drought is among the main abiotic factors causing agronomical losses worldwide. To minimize its impact, several strategies have been proposed, including the use of plant growth-promoting bacteria (PGPBs), as they have demonstrated roles in counteracting abiotic stress. This aspect has been little explored in emergent crops such as quinoa, which has the potential to contribute to reducing food insecurity. Thus, here we hypothesize that the genotype, water environment and the type of inoculant are determining factors in shaping quinoa rhizosphere bacterial communities, affecting plant performance. To address this, two different quinoa cultivars (with contrasting water stress tolerance), two water conditions (optimal and limiting water conditions) and different soil infusions were used to define the relevance of these factors. Different bacterial families that vary among genotypes and water conditions were identified. Certain families were enriched under water stress conditions, such as the Nocardioidaceae, highly present in the water-sensitive cultivar F15, or the Pseudomonadaceae, Burkholderiaceae and Sphingomonadaceae, more abundant in the tolerant cultivar F16, which also showed larger total polyphenol content. These changes demonstrate that the genotype and environment highly contribute to shaping the root-inhabiting bacteria in quinoa, and they suggest that this plant species is a great source of PGPBs for utilization under water-liming conditions.

Shotgun proteomics of quinoa seeds reveals chitinases enrichment under rainfed conditions.

Quinoa is an Andean crop whose cultivation has been extended to many different parts of the world in the last decade. It shows a great capacity for adaptation to diverse climate conditions, including environmental stressors, and, moreover, the seeds are very nutritious in part due to their high protein content, which is rich in essential amino acids. They are gluten-free seeds and contain good amounts of other nutrients such as unsaturated fatty acids, vitamins, or minerals. Also, the use of quinoa hydrolysates and peptides has been linked to numerous health benefits. Altogether, these aspects have situated quinoa as a crop able to contribute to food security worldwide. Aiming to deepen our understanding of the protein quality and function of quinoa seeds and how they can vary when this crop is subjected to water-limiting conditions, a shotgun proteomics analysis was performed to obtain the proteomes of quinoa seeds harvested from two different water regimes in the field: rainfed and irrigated conditions. Differentially increased levels of proteins determined in seeds from each field condition were analysed, and the enrichment of chitinase-related proteins in seeds harvested from rainfed conditions was found. These proteins are described as pathogen-related proteins and can be accumulated under abiotic stress. Thus, our findings suggest that chitinase-like proteins in quinoa seeds can be potential biomarkers of drought. Also, this study points to the need for further research to unveil their role in conferring tolerance when coping with water-deficient conditions.

Unique nutritional features that distinguish Amaranthus cruentus L. and Chenopodium quinoa Willd seeds.

Univariate (Analysis of Variance_ANOVA) and multivariate (Principal Component Analysis (PCA) and Canonical Discriminant Analysis (CDA)) analyses were performed in order to classify and authenticate the seeds from different varieties of quinoa (Chenopodium quinoa Will.), and amaranth (Amaranthus cruentus L.). The univariate analysis showed differences between species for sucrose, K, Ca, unsaturated fatty acids, and the ω6/ω3 ratio. Nevertheless, to strengthen this classification, a PCA was applied separating the samples in 2 groups; group 1, formed by quinoa seeds, presented higher contents of margaroleic, eicosadienoic, behenic, erucic, linolenic, linoleic, and gadoleic acids, proteins, sucrose, and total sugars. Group 2, formed by amaranth seeds, showed positive values for Mn, Mg, Fe, P, Zn, Ca, fiber, glucose, and ω6/ω3 ratio. Furthermore, the CDA models developed resulted in a probability of event of 100% when classifying the samples in the groups quinoa or amaranth, highlighting the good sensitivity of the models used.

Changes in nutritional quality-related traits of quinoa seeds under different storage conditions.

Within the context of climate change and its impact on global food security, seed storage has become key, as it ensures long-term food and next-season seed preservation. Aiming at evaluating quality-related changes in quinoa seeds over storage time, different storage temperatures (-20, 4, 12, 25, and 37°C) and humidity conditions (use of silica gel or not) were studied and different seed nutritional parameters were evaluated at different points during a year of storage. Also, to determine if these variations could be conditioned by the genotype used, two quinoa cultivars were compared. The results proved that quinoa seed quality is highly dependent on the storage temperature but is not consistently affected by the use of silica gel if the seed moisture content (SMC) is kept between 5 and 12%. Furthermore, quality can be maintained and even improved by keeping SMC lower than 12% and storage temperatures low (4°C). Under these conditions (at 4°C in hermetic packaging with or without silica gel), and after 12 months of storage, there was an increase in amino acids like isoleucine, serine, arginine, glycine, and glutamic acid and in seed viability and germination. On the contrary, quinoa seeds stored at 37°C showed an accumulation of reactive oxygen species (ROS) which was related to a lower antioxidant capacity and a reduction in the contents of essential amino acids like isoleucine, lysine, histidine, and threonine, resulting in a delayed and reduced germination capacity, and, therefore, lower seed quality. Besides, quality-related differences appeared between cultivars highlighting differences linked to the genotype. Overall, this work demonstrates that optimal storage temperatures and SMC can preserve or even improve quinoa seed nutritional quality, which in turn can impact food safety and agriculture.

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.

Table Grapes during Postharvest Storage: A Review of the Mechanisms Implicated in the Beneficial Effects of Treatments Applied for Quality Retention.

Table grape is a fruit with increasing interest due to its attributes and nutritional compounds. During recent years, new cultivars such as those without seeds and with new flavors have reached countries around the world. For this reason, postharvest treatments that retain fruit quality need to be improved. However, little is known to date about the biochemical and molecular mechanisms related with observed quality improvements. This review aims to examine existing literature on the different mechanisms. Special attention will be placed on molecular mechanisms which activate and regulate the different postharvest treatments applied in order to improve table grape quality.