Impact of Cross-Breeding of Low Phytic Acid MIPS1 and IPK1 Soybean ( Glycine max L. Merr.) Mutants on Their Contents of Inositol Phosphate Isomers

Soybean genetics, genomics, and breeding for improving nutritional value and reducing antinutritional traits in food and feed

Soybean [Glycine max (L.) Merr.] is a globally important crop due to its valuable seed composition, versatile feed, food, and industrial end-uses, and consistent genetic gain. Successful genetic gain in soybean has led to widespread adaptation and increased value for producers, processors, and consumers. Specific focus on the nutritional quality of soybean seed composition for food and feed has further elucidated genetic knowledge and bolstered breeding progress. Seed components are historical and current targets for soybean breeders seeking to improve nutritional quality of soybean. This article reviews genetic and genomic foundations for improvement of nutritionally important traits, such as protein and amino acids, oil and fatty acids, carbohydrates, and specific food-grade considerations; discusses the application of advanced breeding technology such as CRISPR/Cas9 in creating seed composition variations; and provides future directions and breeding recommendations regarding soybean seed composition traits.

Alginate enriched with phytic acid for hydrogels preparation. Therapeutic applications

In the last decade, numerous innovative strategies have been used to obtain highly efficient synthetic or semi-synthetic biomaterials. Between these innovative biomaterials, hydrogels occupy a distinct place due to their superior biological and physico-chemical characteristics. Alginate is a natural linear polysaccharide with important physico-chemical and biological properties. Recently, we obtained a new hydrogel based on alginate and phytic acid with improved physico-chemical properties. In the present study, the hydrogels previously obtained were tested in terms of their biological properties and possibilities of use in the biomedical field. For this purpose, the hydrogels were loaded with norfloxacin (NRF), an antibacterial compound utilised in the treatment against Gram-negative and Gram-positive organisms. Unfortunately, NRF has low solubility and permeability. In order to provide protection against loss, but also for enhanced bioavailability, and controlled-release of norfloxacin, a drug inclusion complex with cyclodextrin was realized. The effect of complexation on the release profile was highlighted. The addition of NRF to the hydrogel matrices greatly improved the antibacterial activity of the tested compounds. The presence of CD did not affect the homogeneity of the drug distribution. Changes in the polymeric matrix structure were registered after the incorporation of the drug, which were attributed to the relaxation of the network subsequently to the penetration and diffusion of the drug solution simultaneously with the swelling process. The release of NRF from Alg_PA polymeric network has been successfully modulated by the use of CD as a host molecule.

Transcriptome analysis identifies differentially expressed genes in the progenies of a cross between two low phytic acid soybean mutants

Phytic acid (PA) is a major antinutrient that cannot be digested by monogastric animals, but it can decrease the bioavailability of micronutrients (e.g., Zn and Fe). Lowering the PA content of crop seeds will lead to enhanced nutritional traits. Low-PA mutant crop lines carrying more than one mutated gene (lpa) have lower PA contents than mutants with a single lpa mutant gene. However, little is known about the link between PA pathway intermediates and downstream regulatory activities following the mutation of these genes in soybean. Consequently, we performed a comparative transcriptome analysis using an advanced generation recombinant inbred line with low PA levels [2mlpa (mips1/ipk1)] and a sibling line with homozygous non-mutant alleles and normal PA contents [2MWT (MIPS1/IPK1)]. An RNA sequencing analysis of five seed developmental stages revealed 7945 differentially expressed genes (DEGs) between the 2mlpa and 2MWT seeds. Moreover, 3316 DEGs were associated with 128 metabolic and signal transduction pathways and 4980 DEGs were annotated with 345 Gene Ontology terms related to biological processes. Genes associated with PA metabolism, photosynthesis, starch and sucrose metabolism, and defense mechanisms were among the DEGs in 2mlpa. Of these genes, 36 contributed to PA metabolism, including 22 genes possibly mediating the low-PA phenotype of 2mlpa. The expression of most of the genes associated with photosynthesis (81 of 117) was down-regulated in 2mlpa at the late seed developmental stage. In contrast, the expression of three genes involved in sucrose metabolism was up-regulated at the late seed developmental stage, which might explain the high sucrose content of 2mlpa soybeans. Furthermore, 604 genes related to defense mechanisms were differentially expressed between 2mlpa and 2MWT. In this study, we detected a low PA content as well as changes to multiple metabolites in the 2mlpa mutant. These results may help elucidate the regulation of metabolic events in 2mlpa. Many genes involved in PA metabolism may contribute to the substantial decrease in the PA content and the moderate accumulation of InsP3-InsP5 in the 2mlpa mutant. The other regulated genes related to photosynthesis, starch and sucrose metabolism, and defense mechanisms may provide additional insights into the nutritional and agronomic performance of 2mlpa seeds.

Diverse role of phytic acid in plants and approaches to develop low-phytate grains to enhance bioavailability of micronutrients

Natural or synthetic compounds that interfere with the bioavailability of nutrients are called antinutrients. Phytic acid (PA) is one of the major antinutrients present in the grains and acts as a chelator of micronutrients. The presence of six reactive phosphate groups in PA hinders the absorption of micronutrients in the gut of non-ruminants. Consumption of PA-rich diet leads to deficiency of minerals such as iron and zinc among human population. On the contrary, PA is a natural antioxidant, and PA-derived molecules function in various signal transduction pathways. Therefore, optimal concentration of PA needs to be maintained in plants to avoid adverse pleiotropic effects, as well as to ensure micronutrient bioavailability in the diets. Given this, the chapter enumerates the structure, biosynthesis, and accumulation of PA in food grains followed by their roles in growth, development, and stress responses. Further, the chapter elaborates on the antinutritional properties of PA and explains the conventional breeding and transgene-based approaches deployed to develop low-PA varieties. Studies have shown that conventional breeding methods could develop low-PA lines; however, the pleiotropic effects of these methods viz. reduced yield, embryo abnormalities, and poor seed quality hinder the use of breeding strategies. Overexpression of phytase in the endosperm and RNAi-mediated silencing of genes involved in myo-inositol biosynthesis overcome these constraints. Next-generation genome editing approaches, including CRISPR-Cas9 enable the manipulation of more than one gene involved in PA biosynthesis pathway through multiplex editing, and scope exists to deploy such tools in developing varieties with optimal PA levels.

Towards understanding the antagonistic activity of phytic acid against common foodborne bacterial pathogens using a general linear model

The increasing challenge of antibiotic resistance requires not only the discovery of new antibiotics, but also the development of new alternative approaches. Therefore, in the present study, we investigated for the first time the antibacterial potential of phytic acid (myo-inositol hexakisphosphate, IP6), a natural molecule that is 'generally recognized as safe' (FDA classification), against the proliferation of common foodborne bacterial pathogens such as Listeria monocytogenes, Staphylococcus aureus and Salmonella Typhimurium. Interestingly, compared to citric acid, IP6 was found to exhibit significantly greater inhibitory activity (P<0.05) against these pathogenic bacteria. The minimum inhibitory concentration of IP6 varied from 0.488 to 0.97 mg/ml for the Gram-positive bacteria that were tested, and was 0.244 mg/ml for the Gram-negative bacteria. Linear and general models were used to further explore the antibacterial effects of IP6. The developed models were validated using experimental growth data for L. monocytogenes, S. aureus and S. Typhimurium. Overall, the models were able to accurately predict the growth of L. monocytogenes, S. aureus, and S. Typhimuriumin Polymyxin acriflavine lithium chloride ceftazidime aesculin mannitol (PALCAM), Chapman broth, and xylose lysine xeoxycholate (XLD) broth, respectively. Remarkably, the early logarithmic growth phase of S. Typhimurium showed a rapid and severe decrease in a period of less than one hour, illustrating the bactericidal effect of IP6. These results suggest that IP6 is an efficient antibacterial agent and can be used to control the proliferation of foodborne pathogens. It has promising potential for environmentally friendly applications in the food industry, such as for food preservation, food safety, and for prolonging shelf life.

Phytic Acid Contents and Metabolite Profiles of Progenies from Crossing Low Phytic Acid OsMIK and OsMRP5 Rice (Oryza sativa L.) Mutants

The impact of cross-breeding two low phytic acid (lpa) rice mutants on the content of phytic acid and the metabolite profile of the resulting double mutant was investigated. Progenies resulting from the cross of Os-lpa-XS110-1, a rice mutant carrying the myo-inositol kinase (OsMIK) mutated gene, and Os-lpa-XS110-2, with the multidrug resistance-associated protein ABC transporter gene 5 (OsMRP5) as the mutation target, were subjected to high-pressure ion chromatography. The reduction of the phytic acid content in the double mutant (-63%) was much more pronounced than in the single mutants (-26 and -47%). Gas chromatography-based metabolite profiling revealed a superimposition of the metabolite profiles inherited from the lpa progenitors in the double mutant progenies; the resulting metabolite signature was predominated by the OsMIK mutation effect. The study demonstrated that cross-breeding of two single lpa mutants can be employed to generate double lpa rice mutants showing both a significant reduction in the content of phytic acid and the imprinting of a specific mutation-induced metabolite signature.

Stability of the Metabolite Signature Resulting from the MIPS1 Mutation in Low Phytic Acid Soybean ( Glycine max L. Merr.) Mutants upon Cross-Breeding

The low phytic acid ( lpa) soybean ( Glycine max L. Merr.) mutant Gm-lpa-TW-1-M, resulting from a 2 bp deletion in GmMIPS1, was crossed with a commercial cultivar. F3 and F5 progenies were subjected to nontargeted GC-based metabolite profiling, allowing analysis of a broad array of low molecular weight constituents. In the homozygous lpa mutant progenies the intended phytic acid reduction was accompanied by remarkable metabolic changes of nutritionally relevant constituents such as reduced contents of raffinose oligosaccharides and galactosyl cyclitols as well as increased concentrations in sucrose and various free amino acids. The mutation-induced metabolite signature was nearly unaffected by the cross-breeding and consistently expressed over generations and in different growing seasons. Therefore, not only the primary MIPS1 lpa mutant but also its progenies might be valuable genetic resources for commercial breeding programs to produce soybean seeds stably exhibiting improved phytate-related and nutritional properties.