Phytoremediation of Hg and chlorpyrifos contaminated soils using Phaseolus vulgaris L. with biochar, mycorrhizae, and compost amendments.

Anthropogenic activities, encompassing vast agricultural and industrial operations around the world, exert substantial pressure on the environment, culminating in profound ecological impacts. These activities exacerbate soil contamination problems with pollutants such as mercury (Hg) and chlorpyrifos (CPF) that are notable for their widespread presence and detrimental effects. The objective of this study is to evaluate the phytoremediation potential of Phaseolus vulgaris L., augmented with various combinations of biochar, mycorrhizal, and compost amendments, as a sustainable alternative for the remediation of soils contaminated with Hg and CPF. For this purpose, soil from a mining area with mercury contamination has been taken, to which CPF has been added in different concentrations. Then, previously germinated Phaseolus vulgaris L. seedlings with an average height of 10 cm were planted. Electrical conductivity, pH, organic matter, CPF, and Hg, as well as seedling growth parameters, have been evaluated to determine the processes of absorption of soil contaminants into the plant. A combination of biochar with mycorrhiza has been found to be an optimal choice for CPF and Hg remediation. However, all amendments have proven to be efficient in the remediation processes of the tested contaminants.

Transcriptome analysis reveals biosynthesis and regulation of flavonoid in common bean seeds during grain filling.

The Andean domesticated common beans (Phaseolus vulgaris) are significant sources of phenolic compounds associated with health benefits. However, the regulation of biosynthesis of these compounds during bean seed development remains unclear. To elucidate the gene expression patterns involved in the regulation of the flavonoid pathway, we conducted a transcriptome analysis of two contrasting Chilean varieties, Negro Argel (black bean) and Coscorron (white bean), at three developmental stages associated with seed color change, as well as different flavonoid compound accumulations. Our study reveals that phenolic compound synthesis initiates during seed filling, although it exhibits desynchronization between both varieties. We identified 10,153 Differentially Expressed Genes (DEGs) across all comparisons. The KEGG pathway 'Flavonoid biosynthesis' showed enrichment of induced DEGs in Negro Argel (PV172), consistent with the accumulation of delphinidin, petunidin, and malvidin hexosides in their seeds, while catechin glucoside, procyanidin and kaempferol derivatives were predominantly detected in Coscorrón (PV24). Furthermore, while the flavonoid pathway was active in both varieties, our results suggest that enzymes involved in the final steps, such as ANS and UGT, were crucial, inducing anthocyanin formation in Negro Argel. Additionally, during active anthocyanin biosynthesis, the accumulation of reserve proteins or those related to seed protection and germination was induced. These findings provide valuable insights and serve as a guide for plant breeding aimed at enhancing the health and nutritional properties of common beans.

Metabolomic analysis reveals stress tolerance mechanisms in common bean (Phaseolus vulgaris L.) related to treatment with a biostimulant obtained from Corynebacterium glutamicum.

Microbial biostimulants have emerged as a sustainable alternative to increase the productivity and quality of important crops. Despite this, the effects of the treatment on plant metabolism are poorly understood. Thus, this study investigated the metabolic response of common bean (Phaseolus vulgaris) related to the treatment with a biostimulant obtained from the extract of Corynebacterium glutamicum that showed positive effects on the development, growth, and yield of crops previously. By untargeted metabolomic analysis using UHPLC-MS/MS, plants and seeds were subjected to treatment with the biostimulant. Under ideal growth conditions, the plants treated exhibited higher concentration levels of glutamic acid, nicotiflorin and glycosylated lipids derived from linolenic acid. The foliar application of the biostimulant under water stress conditions increased the chlorophyll content by 17% and induced the accumulation of flavonols, mainly quercetin derivatives. Also, germination seed assays exhibited longer radicle lengths for seeds treated compared to the untreated control even in the absence of light (13-18% increase, p-value <0.05). Metabolomic analysis of the seeds indicated changes in concentration levels of amino acids (tryptophan, phenylalanine, tyrosine, glutamine, and arginine) and their derivatives. The results point out the enhancement of abiotic stress tolerance and the metabolic processes triggered in this crop associated with the treatment with the biostimulant, giving the first insights into stress tolerance mechanisms in P. vulgaris.

CRK12: A Key Player in Regulating the Phaseolus vulgaris-Rhizobium tropici Symbiotic Interaction.

Cysteine-rich receptor-like kinases (CRKs) are a type of receptor-like kinases (RLKs) that are important for pathogen resistance, extracellular reactive oxygen species (ROS) signaling, and programmed cell death in plants. In a previous study, we identified 46 CRK family members in the Phaseolus vulgaris genome and found that CRK12 was highly upregulated under root nodule symbiotic conditions. To better understand the role of CRK12 in the Phaseolus-Rhizobia symbiotic interaction, we functionally characterized this gene by overexpressing (CRK12-OE) and silencing (CRK12-RNAi) it in a P. vulgaris hairy root system. We found that the constitutive expression of CRK12 led to an increase in root hair length and the expression of root hair regulatory genes, while silencing the gene had the opposite effect. During symbiosis, CRK12-RNAi resulted in a significant reduction in nodule numbers, while CRK12-OE roots showed a dramatic increase in rhizobial infection threads and the number of nodules. Nodule cross sections revealed that silenced nodules had very few infected cells, while CRK12-OE nodules had enlarged infected cells, whose numbers had increased compared to controls. As expected, CRK12-RNAi negatively affected nitrogen fixation, while CRK12-OE nodules fixed 1.5 times more nitrogen than controls. Expression levels of genes involved in symbiosis and ROS signaling, as well as nitrogen export genes, supported the nodule phenotypes. Moreover, nodule senescence was prolonged in CRK12-overexpressing roots. Subcellular localization assays showed that the PvCRK12 protein localized to the plasma membrane, and the spatiotemporal expression patterns of the CRK12-promoter::GUS-GFP analysis revealed a symbiosis-specific expression of CRK12 during the early stages of rhizobial infection and in the development of nodules. Our findings suggest that CRK12, a membrane RLK, is a novel regulator of Phaseolus vulgaris-Rhizobium tropici symbiosis.

Low doses of glyphosate do not damage the secondary metabolism of common bean.

Glyphosate application, even in low doses, changes the metabolism of crops. This research aimed to evaluate the effects of glyphosate low doses and sowing season on metabolic changes of early-cycle common beans. Two experiments were conducted in the field, one in the winter season and one in the wet season. The experimental design was a randomized complete block design consisting of the application of glyphosate low doses [0.0, 1.8, 7.2, 12.0, 36.0, 54.0, and 108.0 g acid equivalent (a.e.) ha-1] in the phenological stage V4 with four replications. In the winter season, glyphosate and shikimic acid were increased five days after the application of treatments. In contrast, the same compounds increased only at doses of 36 g a.e. ha-1 and above in the wet season. The dose of 7.2 g a.e. ha-1 increased phenylalanine ammonia-lyase and benzoic acid in the winter season. The doses of 54 and 108 g a.e. ha-1 increased benzoic acid, caffeic acid, and salicylic acid. Our study indicated that glyphosate low doses increase the concentration of shikimic, benzoic, salicylic and caffeic acid, PAL and tyrosine. There was no reduction in aromatic amino acids and in secondary compounds from the shikimic acid pathway.

The Phaseolus vulgaris Receptor-Like Kinase PvFER1 and the Small Peptides PvRALF1 and PvRALF6 Regulate Nodule Number as a Function of Nitrate Availability.

Legumes associate with Gram-negative soil bacteria called rhizobia, resulting in the formation of a nitrogen-fixing organ, the nodule. Nodules are an important sink for photosynthates for legumes, so these plants have developed a systemic regulation mechanism that controls their optimal number of nodules, the so-called autoregulation of nodulation (AON) pathway, to balance energy costs with the benefits of nitrogen fixation. In addition, soil nitrate inhibits nodulation in a dose-dependent manner, through systemic and local mechanisms. The CLE family of peptides and their receptors are key to tightly controlling these inhibitory responses. In the present study, a functional analysis revealed that PvFER1, PvRALF1, and PvRALF6 act as positive regulators of the nodule number in growth medium containing 0 mM of nitrate but as negative regulators in medium with 2 and 5 mM of nitrate. Furthermore, the effect on nodule number was found to be consistent with changes in the expression levels of genes associated with the AON pathway and with the nitrate-mediated regulation of nodulation (NRN). Collectively, these data suggest that PvFER1, PvRALF1, and PvRALF6 regulate the optimal number of nodules as a function of nitrate availability.

Rhizobia induce SYMRK endocytosis in Phaseolus vulgaris root hair cells.

MAIN CONCLUSION: PvSYMRK-EGFP undergoes constitutive and rhizobia-induced endocytosis, which rely on the phosphorylation status of T589, the endocytic YXXØ motif and the kinase activity of the receptor. Legume-rhizobia nodulation is a complex developmental process. It initiates when the rhizobia-produced Nod factors are perceived by specific LysM receptors present in the root hair apical membrane. Consequently, SYMRK (Symbiosis Receptor-like Kinase) becomes active in the root hair and triggers an extensive signaling network essential for the infection process and nodule organogenesis. Despite its relevant functions, the underlying cellular mechanisms involved in SYMRK signaling activity remain poorly characterized. In this study, we demonstrated that PvSYMRK-EGFP undergoes constitutive and rhizobia-induced endocytosis. We found that in uninoculated roots, PvSYMRK-EGFP is mainly associated with the plasma membrane, although intracellular puncta labelled with PvSymRK-EGFP were also observed in root hair and nonhair-epidermal cells. Inoculation with Rhizobium etli producing Nod factors induces in the root hair a redistribution of PvSYMRK-EGFP from the plasma membrane to intracellular puncta. In accordance, deletion of the endocytic motif YXXØ (YKTL) and treatment with the endocytosis inhibitors ikarugamycin (IKA) and tyrphostin A23 (TyrA23), as well as brefeldin A (BFA), drastically reduced the density of intracellular PvSYMRK-EGFP puncta. A similar effect was observed in the phosphorylation-deficient (T589A) and kinase-dead (K618E) mutants of PvSYMRK-EGFP, implying these structural features are positive regulators of PvSYMRK-EGFP endocytosis. Our findings lead us to postulate that rhizobia-induced endocytosis of SYMRK modulates the duration and amplitude of the SYMRK-dependent signaling pathway.

Carbon-concentrating mechanisms in pods are key elements for terminal drought resistance in Phaseolus vulgaris.

Common bean (Phaseolus vulgaris L.) is one of the most consumed legumes in the human diet and a substantial source of dietary protein. A major problem for this rainfed crop is the decrease in grain yield caused by prolonged drought periods during the reproductive stage of plant development (terminal drought). Terminal drought remains a prevailing threat to the farming of this staple, with losses reaching >80%. Based on the high correlation between the resistance of common bean to terminal drought and efficient photoassimilate mobilization and biomass accumulation in seeds, we aimed to identify mechanisms implicated in its resistance to this stress. We used two representative Durango race common bean cultivars with contrasting yields under terminal drought, grown under well-watered or terminal drought conditions. Using comparative transcriptomic analysis focused on source leaves, pods, and seeds from both cultivars, we provide evidence indicating that under terminal drought the resistant cultivar promotes the build-up of transcripts involved in recycling carbon through photosynthesis, photorespiration, and CO2-concentrating mechanisms in pod walls, while in seeds, the induced transcripts participate in sink strength and respiration. Physiological data support this conclusion, implicating their relevance as key processes in the plant response to terminal drought.

The Common Bean Small Heat Shock Protein Nodulin 22 from Phaseolus vulgaris L. Assembles into Functional High-Molecular-Weight Oligomers.

Small heat shock proteins (sHsps) are present in all domains of life. These proteins are responsible for binding unfolded proteins to prevent their aggregation. sHsps form dynamic oligomers of different sizes and constitute transient reservoirs for folding competent proteins that are subsequently refolded by ATP-dependent chaperone systems. In plants, the sHsp family is rather diverse and has been associated with the ability of plants to survive diverse environmental stresses. Nodulin 22 (PvNod22) is an sHsp of the common bean (Phaseolus vulgaris L.) located in the endoplasmic reticulum. This protein is expressed in response to stress (heat or oxidative) or in plant roots during mycorrhizal and rhizobial symbiosis. In this work, we study its oligomeric state using a combination of in silico and experimental approaches. We found that recombinant PvNod22 was able to protect a target protein from heat unfolding in vitro. We also demonstrated that PvNod22 assembles into high-molecular-weight oligomers with diameters of ~15 nm under stress-free conditions. These oligomers can cluster together to form high-weight polydisperse agglomerates with temperature-dependent interactions; in contrast, the oligomers are stable regarding temperature.

Agronomic biofortification increases concentrations of zinc and storage proteins in common bean (Phaseolus vulgaris L.) grains.

Zinc (Zn) is an essential element for plants and mammals and its deficiency affects billions of people worldwide. This study aimed to evaluate the effects of soil Zn fertilization and foliar Zn sprays in different phenological stages of the plant on the grain nutritional quality of common bean (Phaseolus vulgaris L.). Field experiments were carried out in two consecutive harvest years under no-till system in an Oxisol. Two commercial common bean cultivars were used: BRS Esteio (black bean) and IPR Campos Gerais (Carioca bean). Total concentration of Zn, amino acids, sucrose, total sugars and storage proteins (albumin, globulin, glutelin and prolamin) in grains were evaluated. The cultivar BRS Esteio exhibited higher grain enrichment with Zn than the cultivar IPR Campos Gerais, showing genotypic variation. Single foliar Zn spray of 600 g ha-1 at the initial grain filling stage was shown to be the best way to improve the grain Zn concentration, without affecting grain yield. Foliar Zn spray at the final stage of grain filling favored the increase of Zn concentration in the pods over the Zn concentration in the grains. Agronomic biofortification of bean grains with Zn was more efficient with foliar Zn spraying than with the soil Zn fertilization, however, the soil Zn application favored the increase of concentrations of total amino acids and storage proteins (albumin, globulin and glutelin) in the grains. Agronomic biofortification proved to be efficient in increasing concentrations of Zn and storage proteins in common bean grains.

Monitoring Stimulated Darkening from UV-C Light on Different Bean Genotypes by NMR Spectroscopy.

The use of UV-C cool white light on bean (Phaseolus vulgaris L.) seeds significantly increases the biochemical seed coat post-harvest darkening process, whilst preserving seed germination. The aim of this work consists in monitoring the effect caused by the incidence of UV-C light on different bean genotypes using NMR spectroscopy. The genotype samples named IAC Alvorada; TAA Dama; BRS Estilo and BRS Pérola from the Agronomic Institute (IAC; Campinas; SP; Brazil) were evaluated. The following two methodologies were used: a prolonged darkening, in which the grain is placed in a room at a controlled temperature (298 K) and humidity for 90 days, simulating the supermarket shelf; an accelerated darkening, where the grains are exposed to UV-C light (254 nm) for 96 h. The experiments were performed using the following innovative time-domain (TD) NMR approaches: the RK-ROSE pulse sequence; one- and two-dimensional high resolution (HR) NMR experiments (1H; 1H-1H COSY and 1H-13C HSQC); chemometrics tools, such as PLS-DA and heat plots. The results suggest that the observed darkening occurs on the tegument after prolonged (90 days) and accelerated (96 h) conditions. In addition, the results indicate that phenylalanine is the relevant metabolite within this context, being able to participate in the chemical reactions accounted for by the darkening processes. Additionally, it is possible to confirm that a UV-C lamp accelerates oxidative enzymatic reactions and that the NMR methods used were a trustworthy approach to monitor and understand the darkening in bean seeds at metabolite level.

Metallothionein1A Regulates Rhizobial Infection and Nodulation in Phaseolus vulgaris.

Metallothioneins (MTs) constitute a heterogeneous family of ubiquitous metal ion-binding proteins. In plants, MTs participate in the regulation of cell growth and proliferation, protection against heavy metal stress, oxidative stress responses, and responses to pathogen attack. Despite their wide variety of functions, the role of MTs in symbiotic associations, specifically nodule-fabacean symbiosis, is poorly understood. Here, we analyzed the role of the PvMT1A gene in Phaseolus vulgaris-Rhizobium tropici symbiosis using bioinformatics and reverse genetics approaches. Using in silico analysis, we identified six genes encoding MTs in P. vulgaris, which were clustered into three of the four classes described in plants. PvMT1A transcript levels were significantly higher in roots inoculated with R. tropici at 7 and 30 days post inoculation (dpi) than in non-inoculated roots. Functional analysis showed that downregulating PvMT1A by RNA interference (RNAi) reduced the number of infection events at 7 and 10 dpi and the number of nodules at 14 and 21 dpi. In addition, nodule development was negatively affected in PvMT1A:RNAi transgenic roots, and these nodules displayed a reduced nitrogen fixation rate at 21 dpi. These results strongly suggest that PvMT1A plays an important role in the infection process and nodule development in P. vulgaris during rhizobial symbiosis.

Silicon supplied via foliar application and root to attenuate potassium deficiency in common bean plants.

Potassium (K) deficiency affects physiological performance and decreases vegetative growth in common bean plants. Although silicon (Si) supplied via nutrient solution or foliar application may alleviate nutritional stress, research on the bean crop is incipient. Thus, two experiments were carried out: initially, a test was performed to determine the best source and foliar concentration of silicon. Subsequently, the chosen Si source was supplied in nutrient solution via roots or foliar application to verify whether Si supply forms are efficient in alleviating the effects of K deficiency. For these purposes, a completely randomized 2 × 3 factorial design was used, with two levels of K: deficient (0.2 mmol L-1 of K) and sufficient (6 mmol L-1 of K); and Si: in nutrient solution via roots (2 mmol L-1 of Si) or foliar application (5.4 mmol L-1 of Si) and control (0 mmol L-1 of Si). Our findings revealed that Si supplied via foliar spraying using the source of sodium silicate and stabilized potassium at a concentration of 5.4 mmol L-1 was agronomically viable for the cultivation of bean plant. K deficiency, when not supplied with silicon, compromised plant growth. Moreover, root-and-foliar-applied Si attenuated the effects of K deficiency as it increased chlorophylls and carotenoids content, photosynthetic activity, water use efficiency and vegetative growth. For the first time, the role of Si to mitigate K deficiency in the bean crop was evidenced, with a view to further research on plants that do not accumulate this beneficial element.

Genome-wide association study for grain mineral content in a Brazilian common bean diversity panel.

KEY MESSAGE: QTNs significantly associated to nine mineral content in grains of common bean were identified. The accumulation of favorable alleles was associated with a gradually increasing nutrient content in the grain. Biofortification is one of the strategies developed to address malnutrition in developing countries, the aim of which is to improve the nutritional content of crops. The common bean (Phaseolus vulgaris L.), a staple food in several African and Latin American countries, has excellent nutritional attributes and is considered a strong candidate for biofortification. The objective of this study was to identify genomic regions associated with nutritional content in common bean grains using 178 Mesoamerican accessions belonging to a Brazilian Diversity Panel (BDP) and 25,011 good-quality single nucleotide polymorphisms. The BDP was phenotyped in three environments for nine nutrients (phosphorus, potassium, calcium, magnesium, copper, manganese, sulfur, zinc, and iron) using four genome-wide association multi-locus methods. To obtain more accurate results, only quantitative trait nucleotides (QTNs) that showed repeatability (i.e., those detected at least twice using different methods or environments) were considered. Forty-eight QTNs detected for the nine minerals showed repeatability and were considered reliable. Pleiotropic QTNs and overlapping genomic regions surrounding the QTNs were identified, demonstrating the possible association between the deposition mechanisms of different nutrients in grains. The accumulation of favorable alleles in the same accession was associated with a gradually increasing nutrient content in the grain. The BDP proved to be a valuable source for association studies. The investigation of different methods and environments showed the reliability of markers associated with minerals. The loci identified in this study will potentially contribute to the improvement of Mesoamerican common beans, particularly carioca and black beans, the main groups consumed in Brazil.

Priming of seeds with INA and its transgenerational effect in common bean (Phaseolus vulgaris L.) plants.

Priming is a mechanism of defense that prepares the plant's immune system for a faster and/or stronger activation of cellular defenses against future exposure to different types of stress. This enhanced resistance can be achieved by using inorganic and organic compounds which imitate the biological induction of systemic acquired resistance. INA (2,6 dichloro-isonicotinic acid) was the first synthetic compound created as a resistance inducer for plant-pathogen interactions. However, the use of INA to activate primed resistance in common bean, at the seed stage and during germination, remains experimentally unexplored. Here, we test the hypothesis that INA-seed treatment would induce resistance in common bean plants to Pseudomonas syringae pv. phaseolicola, and that the increased resistance is not accompanied by a tradeoff between plant defense and growth. Additionally, it was hypothesized that treating seeds with INA has a transgenerational priming effect. We provide evidence that seed treatment activates a primed state for disease resistance, in which low nucleosome enrichment and reduced histone activation marks during the priming phase, are associated with a defense-resistant phenotype, characterized by symptom appearance, pathogen accumulation, yield, and changes in gene expression. In addition, the priming status for induced resistance can be inherited to its offspring.

Phaseolus vulgaris MIR1511 genotypic variations differentially regulate plant tolerance to aluminum toxicity.

The common-bean (Phaseolus vulgaris), a widely consumed legume, originated in Mesoamerica and expanded to South America, resulting in the development of two geographically distinct gene pools. Poor soil condition, including metal toxicity, are often constraints to common-bean crop production. Several P. vulgaris miRNAs, including miR1511, respond to metal toxicity. The MIR1511 gene sequence from the two P. vulgaris model sequenced genotypes revealed that, as opposed to BAT93 (Mesoamerican), the G19833 (Andean) accession displays a 58-bp deletion, comprising the mature and star miR1511 sequences. Genotyping-By-Sequencing data analysis from 87 non-admixed Phaseolus genotypes, comprising different Phaseolus species and P. vulgaris populations, revealed that all the P. vulgaris Andean genotypes and part of the Mesoamerican (MW1) genotypes analyzed displayed a truncated MIR1511 gene. The geographic origin of genotypes with a complete versus truncated MIR1511 showed a distinct distribution. The P. vulgaris ALS3 (Aluminum Sensitive Protein 3) gene, known to be important for aluminum detoxification in several plants, was experimentally validated as the miR1511 target. Roots from BAT93 plants showed decreased miR1511 and increased ALS3 transcript levels at early stages under aluminum toxicity (AlT), while G19833 plants, lacking mature miR1511, showed higher and earlier ALS3 response. Root architecture analyses evidenced higher tolerance of G19833 plants to AlT. However, G19833 plants engineered for miR1511 overexpression showed lower ALS3 transcript level and increased sensitivity to AlT. Absence of miR1511 in Andean genotypes, resulting in a diminished ALS3 transcript degradation, appears to be an evolutionary advantage to high Al levels in soils with increased drought conditions.

Six months under uncontrolled relative humidity and room temperature changes technological characteristics and maintains the physicochemical and functional properties of carioca beans (Phaseolus vulgaris L.).

Carioca beans contribute to health maintenance around the world, and the evaluation of commercial postharvest storage (CPS) ensures their quality. This study aimed to evaluate the effect of CPS on technological, physicochemical and functional properties of carioca beans. Two genotypes (Pontal-PO and Madreperola-MP beans) were stored under CPS or controlled conditions and were evaluated after harvest and after three- and six-months storage. PO and MP hardened with time, but the cooking time did not differ. PO is darker than MP and both darkened over time. Storage time affected pH and acidity of the beans and MP presented better physicochemical properties than PO, with lower activity of peroxidase (p = 0.004) and polyphenoloxidase (p = 0.001) enzymes. Glycosylated kaempferol was suggested as a possible chemical marker to differentiate the aging of PO and MP beans. In conclusion, besides the technological differences, the storage was able to prevent physicochemical and functional alterations of beans.

The influence of chemical composition diversity in the cooking quality of Andean bean genotypes.

Andean beans (Phaseolus vulgaris) chemical compositions and cooking characteristics contribute to a healthy diet. The objective of this study was to evaluate the influence of chemical composition on the cooking quality of 14 Andean beans genotypes with different seed coat colors. More specifically, water retention (WR), cooking time (CT), and solids released in the broth, were analysed. WR values ranged from 128.4% to 160.7% and CT ranged from 13.7 (BRS Embaixador) to 21.7 min (KID44). Andean beans showed variability in chemical composition, mainly starch content (39.43 g 100 g-1, BRS Realce to 51.92 g 100 g-1, LP15-04) and polymer composition. The profile of starch and interactions among minerals and chemical compounds influenced the cooking profiles than do the individual compounds. Andean beans traits of cooking, mainly CT, were influenced by their chemical composition; however they can be incorporated into diets without drastic changes in preparation methods.

Macronutrient deficiency in snap bean considering physiological, nutritional, and growth aspects.

Nutritional deficiencies limit the growth of snap bean plants, therefore knowing the biological mechanisms involved in it is fundamental. This study is aimed to evaluate the damage caused by a deficiency of macronutrients in physiological variables that cause decreased growth and the appearance of visual symptoms in snap bean. Thus, we design a hydroponic system of snap bean cultivation in order to test the effect of macronutrient deficiencies in a controlled environment. The treatments consisted in evaluate the effects of lack of one macronutrient in time. To perform this, we used Hoagland and Arnon solution in its complete formulation (control) or without N, P; K; Mg, Ca or S in each treatment. Physiological, nutritional, and growth analyses were performed when visual deficiency symptoms of each omitted nutrient appeared. Thus, the omissions of N and P in the nutrient solution led to lower accumulations of all macronutrients in the shoot. And the K, Ca, Mg, and S omissions decreased the amounts of K, Ca, Mg, P, and S in the shoot of the snap bean plants when compared with the plants grown in the complete nutrient solution. With the lowest accumulation of macronutrients, the content of photosynthetic pigments and the photosynthetic rate were reduced, with harmful effects on plant growth. Thus, from the losses in dry matter production of the shoot, the order of limiting of macronutrients in bean plants was N < P < Ca < S < Mg < K, with a decrease of up to 86.2%, 80.1%, 51.2%, 46.5%, 25.6%, and 19.3%, respectively. The nitrogen deficiency is more evident, proven by symptoms such as chlorosis in the lower and upper third leaves and necrosis of the lower third leaves.

Effect of Instant Controlled Pressure-Drop on the Non-Nutritional Compounds of Seeds and Sprouts of Common Black Bean (Phaseolus vulgaris L.).

The common bean is an important caloric-protein food source. However, its nutritional value may be affected by the presence of non-nutritional compounds, which decrease the assimilation of some nutrients; however, at low concentrations, they show a beneficial effect. Germination and treatment by controlled pressure-drop (DIC, French acronym of Détente Instantanée Contrôlée) are methods that modify the concentration of these components. The objective of this work was to evaluate the change in the non-nutritional composition of bean seeds and sprouts by DIC treatment. The results show that with the germination, the concentration of phenolic and tannin compounds increased 99% and 73%, respectively, as well as the quantity of saponins (65.7%), while phytates and trypsin inhibitors decreased 26% and 42%, respectively. When applying the DIC treatment, the content of phytates (23-29%), saponins (44%) and oligosaccharides increased in bean sprouts and decreased phenolic compounds (4-14%), tannins (23% to 72%), and trypsin inhibitors (95.5%), according to the pressure and time conditions applied. This technology opens the way to new perspectives, especially to more effective use of legumes as a source of vegetable protein or bioactive compounds.