A novel method for detecting conformation-dependent β-glucans-single, double, and triple-helical from Shiitake mushroom

This pioneering study explores the structural intricacies of therapeutic β-glucan in Shiitake (Lentinula edodes), i.e. Lentinan (LNT). Lentinan, a neutral polysaccharide [β-(1,3; 1,6) glucan], exists in three forms; single, double, and triple-helical, but conformation-dependent bioactivity studies are lacking. In this context, we meticulously assessed indigenous Shiitake accessions from Northeast India, unveiling the conformational spectrum of LNT through an innovative pipeline. The experiment approached the simultaneous estimation of total glucan (TG), triple helical glucan (THG), and single-double helical glucan (SDG). Profiling revealed the exceptional LNT content in DMRO-623 (TG: 46.74%, SDG: 9.34%, THG: 37.39%) which emerged as the highest documented to date. Beyond the culinary delight, this research and the novel approach to LNT quantification will create a pivotal platform for advanced mushroom research, offering prospects for novel discoveries, innovative applications, and therapeutic potential.

Isoflavones Play a Potential Role in Off-Flavour Scavenging, with a Key Role of IFS2 in Isoflavone Accumulation in Soybean Seeds

Research background

Soybean (Glycine max (L.) Merr) is a nutrient-rich crop with a high protein content and various bioactive compounds with health-promoting properties. Nevertheless, it is poorly accepted as a food by consumers due to its off-flavour. Due to the ubiquitous presence of isoflavones in soybeans, their inherent antioxidant potential and inhibitory effect on lipoxygenase activity, their sensory properties are currently being considered to mitigate the off-flavour.

Experimental approach

In the present study, the content and composition of isoflavones in 17 soybean cultivars are determined. The correlation between the isoflavone mass fraction and lipid peroxidation was also established, using thiobarbituric acid (TBA) value and carbonyl compound concentration as indices for the development of off-flavour. Cloning, gene expression analysis and in silico analysis of isoflavone synthase isoforms (IFS1 and IFS2) were also performed.

Results and conclusions

The total isoflavone mass fraction in soybean genotypes ranged from (153.5±7.2) µg/g for PUSA 40 to (1146±43) µg/g for Bragg. There was a moderately negative correlation between the indices of off-flavour formation and the genistein/daidzein ratio (p<0.1). However, the correlation with total isoflavone mass fraction was found to be insignificant, indicating complex interactions. Higher protein-protein interactions for the predicted structure of IFS2 with other biosynthesis enzymes and its comparatively higher expression in the Bragg than that of IFS1 indicated its more important role in isoflavone synthesis.

Novelty and scientific contribution

The genistein/daidzein mass ratio was found to be an important factor in controlling off-flavour. IFS2 was identified as key to produce soybeans with high isoflavone mass fraction and potentially lower off-flavour formation.

Comparison of phenotypic and genotypic frequency of phosphine resistance in select field populations of Tribolium castaneum from India

BACKGROUND

Tribolium castaneum causes substantial damage to stored grains, leading to economic losses. The present study evaluates phosphine resistance in adult and larval stages of T. castaneum from north and northeast India, where continuous and long-term phosphine use in large-scale storage conditions intensifies resistance, posing risks to grain quality, safety, and industry profitability.

METHODS AND RESULTS

This study utilized T. castaneum bioassays and CAPS markers restriction digestion methodology to assess resistance. The phenotypic results indicated a lower LC50 value in larvae compared to adults, while the resistance ratio remained consistent across both stages. Similarly, the genotypic analysis revealed comparable resistance levels regardless of the developmental stage. We categorized the freshly collected populations based on resistance ratios, with Shillong showing weak resistance, Delhi and Sonipat displaying moderate resistance, and Karnal, Hapur, Moga, and Patiala exhibiting strong resistance to phosphine. Further validation by accessing findings and exploring the relationship between phenotypic and genotypic variations using Principal Component Analysis (PCA). This comprehensive study enhances our understanding of T. castaneum resistance levels, providing valuable insights for the development of targeted pest management strategies.

CONCLUSION

This study provides insights into the current phenotypic and genotypic resistance levels of T. castaneum in North and North East India. Understanding this is crucial for developing effective pest management strategies and future research on biological and physiological aspects of phosphine resistance in insects, enabling the formulation of effective management practices. Addressing phosphine resistance is vital for sustainable pest management and the long-term viability of the agricultural and food industries.

Soybean (Glycine max) isoflavone conjugate hydrolysing β-glucosidase (GmICHG): a promising candidate for soy isoflavone bioavailability enhancement

Isoflavones are a sub-class of phenylpropanoids having health benefits and a role in plant defence and plant-rhizobium interaction. Isoflavone conjugate hydrolysis is crucial in determining the bioactivity and bioavailability of these isoflavones inside the human body. This study examined the different characteristics of soy isoflavone conjugate hydrolysing β-glucosidase (GmICHG) to explore its potential for isoflavone bioavailability enhancement. We cloned the full-length GmICHG cDNA from the soybean seedling roots from the DS2706 variety of 1545 bp. The bioinformatics analysis revealed secretion and glycosylation of this protein. The evolutionary relatedness of this gene to the other glucosidases interestingly had related sequences outside the Papilionaceae family. The protein had a pI above neutral of 7.62 and optimum pH of 6.0, indicating its activity in the extracellular acidic environment. The GmICHG gene expression at three stages of seedling roots gradually rose to 1.84 ± 0.54 fold and a concomitant increase in the β-glucosidase activity. The enzyme kinetics of GmICHG showed a K m of 6.38 mM and V max of 2.82 U/ml and an optimum temperature of 40 °C. These hint that soy ICHG can be a potent candidate for the isoflavone bioavailability enhancement by hydrolysing their β-glycosidic bonds.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-022-03427-5.

Stability enhancement of beetroot betalains through copigmentation

BACKGROUND

Like other natural pigments, betalains have a stability problem. Copigmentation can be explored to address this issue. In this study, black carrot anthocyanins were used for the first time as copigment with betalains so that copigmented betalains with enhanced stability could be developed to withstand deteriorative processing and storage conditions.

RESULTS

Increase in hyperchromic and bathochromic shift with subsequent increase in black carrot anthocyanin extract (0.250 g L^-1 ) addition from 0.2 to 1.0 mL L^-1 was observed in native betalain pigments from 0.28 to 1.90 and 538 nm to 564 nm, respectively. For maximum recorded bathochromic shift, 0.8 mL L^-1 addition of copigment was optimized. Copigmented betalain pigment showed better stability in comparison with native pigment, when exposed to light, temperature more than 60 °C and ≥1.0 g L^-1 NaCl. At constant incubation time (3 h), copigmented betalains degraded up to 20.79-41.43% whereas the non-copigmented counterpart degraded up to 83.49-86.86% at 60, 75 and 90 °C, respectively. Lower rate constant (k) and enhanced activation energy (E_a ) showed higher thermostability of copigmented betalains. With constant light exposure, the half-life value of betalains was 145.2 h, which increased approximately twofold (274.08 h) after copigmentation. The t_1/2 of betalain pigment at 10%, 15% and 18% salt addition was 81.12, 75.36 and 83.52 h, which increased to 186.96, 226.56 and 152.88 h after copigmentation.

CONCLUSION

These findings support that black carrot anthocyanin is a potential and compatible copigment for water-soluble betalain pigment that enhances stability of betalains under extreme processing conditions. © 2022 Society of Chemical Industry.

Current trends in the development of soy-based foods containing probiotics and paving the path for soy-synbiotics

In the world of highly processed foods, special attention is drawn to the nutrient composition and safety of consumed food products. Foods fortified with probiotic bacteria confer beneficial effects on human health and are categorized as functional foods. The salubrious activities of probiotics include the synthesis of vital bioactives, prevention of inflammatory diseases, anticancerous, hypocholesterolemic, and antidiarrheal effects. Soy foods are exemplary delivery vehicles for probiotics and prebiotics and there are diverse strategies to enhance their functionality like employing mixed culture fermentation, engineering probiotics, and incorporating prebiotics in fermented soy foods. High potential is ascribed to the concurrent use of probiotics and prebiotics in one product, termed as "synbiotics," which implicates synergy, in which a prebiotic ingredient particularly favors the growth and activity of a probiotic micro-organism. The insights on emended bioactive profile, metabolic role, and potential health benefits of advanced soy-based probiotic and synbiotic hold a promise which can be profitably implemented to meet consumer needs. This article reviews the available knowledge about strategies to enhance the nutraceutical potential, mechanisms, and health-promoting effects of advanced soy-based probiotics. Traditional fermentation merged with diverse strategies to improve the efficiency and health benefits of probiotics considered vital, are also discussed.

Interactome of millet-based food matrices: A review

Millets are recently being recognized as emerging food ingredients with multifaceted applications. Whole grain flours made from millets, exhibit diverse chemical compositions, starch digestibility and physicochemical properties. A food matrix can be viewed as a section of food microstructure, commonly coinciding with a physical spatial domain that interacts or imparts specific functionalities to a particular food constituent. The complex millet-based food matrices can help individuals to attain nutritional benefits due to the intricate and unique digestive properties of these foods. This review helps to fundamentally understand the binary and ternary interactions of millet-based foods. Nutritional bioavailability and bioaccessibility are also discussed based on additive, synergistic, masking, the antagonistic or neutralizing effect of different food matrix components on each other and the surrounding medium. The molecular basis of these interactions and their effect on important functional attributes like starch retrogradation, gelling, pasting, water, and oil holding capacity is also discussed.

Role of ATP-binding cassette transporters in maintaining plant homeostasis under abiotic and biotic stresses

The ATP-binding cassette (ABC) transporters belong to a large protein family predominantly present in diverse species. ABC transporters are driven by ATP hydrolysis and can act as exporters as well as importers. These proteins are localized in the membranes of chloroplasts, mitochondria, peroxisomes and vacuoles. ABC proteins are involved in regulating diverse biological processes in plants, such as growth, development, uptake of nutrients, tolerance to biotic and abiotic stresses, tolerance to metal toxicity, stomatal closure, shape and size of grains, protection of pollens, transport of phytohormones, etc. In mitochondria and chloroplast, the iron metabolism and its transport across the membrane are mediated by ABC transporters. Tonoplast-localized ABC transporters are involved in internal detoxification of metal ion; thus protecting against the DNA impairment and maintaining cell growth. ABC transporters are involved in the transport of secondary metabolites inside the cells. Microorganisms also engage a large number of ABC transporters to import and expel substrates decisive for their pathogenesis. ABC transporters also suppress the seed embryonic growth until favorable conditions come. This review aims at giving insights on ABC transporters, their evolution, structure, functions and roles in different biological processes for helping the terrestrial plants to survive under adverse environmental conditions. These specialized plant membrane transporters ensure a sustainable economic yield and high-quality products, especially under unfavorable conditions of growth. These transporters can be suitably manipulated to develop 'Plants for the Future'.

Recent trends in extraction of plant bioactives using green technologies: A review

Phenolic compounds from plant sources have significant health-promoting properties and are known to be an integral part of folk and herbal medicines. Consumption of phenolics is known to alleviate the risk of various lifestyle diseases including cancer, cardiovascular, diabetes, and Alzheimer's. In this context, numerous plant crops have been explored and characterized based on phenolic compounds for their use as supplements, nutraceutical, and pharmaceuticals. The present review highlights some important source of bioactive phenolic compounds and novel technologies for their efficient extraction. These techniques include the use of microwave, ultrasound, and supercritical methods. Besides, the review will also highlight the use of response surface methodology (RSM) as a statistical tool for optimizing the recoveries of the phenolic bioactives from plant-based matrices.

Magnoflorine prevent the skeletal muscle atrophy via Akt/mTOR/FoxO signal pathway and increase slow-MyHC production in streptozotocin-induced diabetic rats

ETHNOPHARMACOLOGICAL RELEVANCE

Tinospora cordifolia (TC) is being used as a blood purifier in Ayurveda since ancient time. It is a very popular immunomodulator and holds anti-inflammatory and anti-oxidative potential, hence anti-aging properties. Therefore, it is also known as 'Amrita' in Ayurveda and is widely used to treat diabetes mellitus type II (T2DM) and its secondary complications; however, its underlying mechanism was not expedited to date. AIM-: To explore the in vivo therapeutic efficiency and mechanism of action of TC and its secondary constitute magnoflorine on the skeletal muscle atrophy in the rat model of T2DM.

METHOD

Animal model of T2DM was developed using streptozotocin (STZ) injection followed by intervention with TC, metformin, and magnoflorine for three weeks. Confirmation of T2DM and abrogation of atrophic markers and possible mechanisms on supplementation of TC and magnoflorine were explored using histology, bio-assays, Western blotting, and q-PCR.

RESULT

TC and Magnoflorine supplementations significantly (p ≤ 0.05) decreased the fasting blood glucose (FBG) levels in T2DM rats. Both treatments prevented the lean body, individual skeletal muscle mass, and myotubes diameter loss (p ≤ 0.05). Magnoflorine significantly reduced the degradation of the protein indicated by biochemical markers of atrophy i.e. decreased serum creatine kinase (CK) levels and increased myosin heavy chain-β (MyHC-β) levels in muscles. Q-PCR and western blotting supported the findings that magnoflorine significantly increased the mRNA and protein abundances (~3 fold) of MyHC-β.TC and magnoflorine efficiently decreased the expression of ubiquitin-proteasomal E3-ligases (Fn-14/TWEAK, MuRF1, and Atrogin 1), autophagy (Bcl-2/LC3B), and caspase related genes along with calpains activities in T2DM rats. Both TC and magnoflorine also increased the activity of superoxide dismutase, GSH-Px, decreased the activities of β-glucuronidase, LPO, and prevented any alteration in the catalase activity. In contrast, magnoflorine increased expression of TNF-α and IL-6 whereas TC and metformin efficiently decreased the levels of these pro-inflammatory cytokines (p ≤ 0.05). However, magnoflorine was found to increase phosphorylation of Akt more efficiently than TC and metformin.

CONCLUSION

TC, and magnoflorine are found to be effective to control fasting blood glucose levels significantly in T2DM rats. It also promoted the Akt phosphorylation, suppressed autophagy and proteolysis that might be related to blood glucose-lowering efficacy of magnoflorine and TC. However, increased muscle weight, specifically of the soleus muscle, expression of IL-6, and slow MyHC indicated the increased myogenesis in response to magnoflorine and independent from its hypoglycemic activity.

Dynamics of Toll-like receptors signaling in skeletal muscle atrophy

Skeletal muscle atrophy has been characterizedas a state of uncontrolled inflammation and oxidative stress that escalates the protein catabolism. Recent advancement supportsthat impinging signaling molecules in the muscle fibers controlled throughtoll-like receptors (TLR). Activated TLR signalingpathways have been identified as inhibitors of muscle mass and provoke the settings for muscle atrophy. Among them, mainly TLR2 and TLR4 manifest their presence to exacerbate the release of the pro-inflammatory cytokine to deform the synchronized muscle programming. The present review enlightens the TLR signaling mediated muscle loss and their interplay betweeninflammationand skeletal muscle growth.

Study of subcellular localization of Glycine max γ-tocopherol methyl transferase isoforms in N. benthamiana

Gamma-tocopherol methyltransferase (γ-TMT) converts γ-toc to α-toc-the rate limiting step in toc biosynthesis. Sequencing results revealed that the coding regions of γ-TMT1 and γ-TMT3 were strongly similar to each other (93% at amino acid level). Based on the differences in the N-terminal amino acids, Glycine max-γ-TMT proteins are categorized into three isoforms: γ-TMT1, 2 and 3. In silico structural analysis revealed the presence of chloroplast transit peptide (cTP) in γ-TMT1 and γ-TMT3 protein. However, other properties of transit peptide like presence of hydrophobic amino acids at the first three positions of N-terminal end and lower level of acidic amino acids were revealed only in γ-TMT3 protein. Subcellular localization of GFP fused γ-TMT1 and γ-TMT3 under 35S promoter was studied in Nicotiana benthamiana using confocal microscopy. Results showed that γ-TMT1 was found in the cytosol and γ-TMT3 was found to be localized both in cytosol and chloroplast. Further the presence γ-TMT3 in chloroplast was validated by quantifying α-tocopherol through UPLC. Thus the present study of cytosolic localization of the both γ-TMT1 and γ-TMT3 proteins and chloroplastic localization of γ-TMT3 will help to reveal the importance of γ-TMT encoded α-toc in protecting both chloroplastic and cell membrane from plant oxidative stress.

Analysis of γ-Tocopherol methyl transferase3 promoter activity and study of methylation patterns of the promoter and its gene body

Soybeans are known for its good source of protein (40%), oil (20%) and also serve as a source of nutraceutical compounds including tocopherols (toc). To know the molecular basis of differential α-toc accumulation in two contrasting soybean genotypes: DS74 (low α-toc - 1.36 μg/g and total-toc -29.72 μg/g) and Bragg (high α-toc - 10.48 μg/g and total-toc 178.91 μg/g), the analysis of γ-TMT3 promoter activity and its methylation patterns were carried out. The sequencing results revealed nucleotide variation between Bragg:γ-TMT3-P and DS74:γ-TMT3-P, however none of the variations were found in core-promoter region or in cis-elements. The histochemical GUS assay revealed higher promoter activity of Bragg:γ-TMT3-P than that of DS74:γ-TMT3-P and correlated with significantly higher and lower (P < 0.05) expression of γ-TMT3 gene respectively. To know the molecular basis of differential accumulation of α-toc in these contrasting soybean genotypes, the DNA methylation pattern of γ-TMT3 gene body and its promoter was studied in both varieties. The results showed higher percentage (62.5%) of methylation in DS74:γ-TMT3-P than in Bragg:γ-TMT3-P (50%). Out of all the methylation sites in the promoter region, one of methylation site was found at CAAT box (-190 bp) of DS74:γ-TMT3-P. Further gene body methylation patterns revealed lowest % (40%) of CG methylation in DS74:γ-TMT3 gene as compared to Bragg:γ-TMT3 (64.2%). Thus our study revealed that, expression of γ-TMT3 gene was influenced by its promoter activity and methylation patterns in cis-elements of γ-TMT3 promoter and gene body. This study will help us to understand the possible role of methylation and promoter activity in determining the α-toc content in soybean seeds.

Evaluation of enzyme and microwave-assisted conditions on extraction of anthocyanins and total phenolics from black soybean (Glycine max L.) seed coat

The present study compares three methods viz. microwave-assisted extraction (MAE), enzyme-assisted extraction (EAE) and conventional solvent extraction (CSE) for extraction of polyphenolic compounds from Black Soybean Seed coat (BSSC). Box-Behnken design using response surface methodology (RSM) was employed to investigate and optimize the MAE and EAE for maximum bioactive content, antioxidant activity, colour density and minimum degradation parameters from BSSC. Optimized MAE conditions for BSSC were: microwave power of 569.46 W, extraction time of 262.54 s, solvent to solid ratio of 40:1 and ethanol concentration (59.99). The predicted anthocyanin content was 5021.47 mg/l, close to experimental optimized value of 5094.9 mg/l with minimum values of degradation parameters viz., Polymeric Colour (PC) (0.131 ± 0.01), Browning Index (BI) (0.202 ± 0.02) and Degradation Index (DI) (0.140 ± 0.02). Overall results clearly indicate that MAE is the best suited method for extraction in comparison to EAE and CSE. The phenolic rich extract can be used as an effective functional ingredient in foods.

Conserved miRNAs modulate the expression of potential transcription factors of isoflavonoid biosynthetic pathway in soybean seeds

Despite the significant importance of soybean isoflavone, the regulatory mechanism of miRNAs during its biosynthesis is highly unexplored. In the present work, nine existing miRNAs along with their ten corresponding target genes were identified and validated in soybean for their possible role during isoflavonoid biosynthesis and accumulation. Temporal expression analysis at four key stages of seed development (35, 45, 55 and 65DAF) of all the miRNA-target pairs showed varying degree of differential accumulation in two soybean genotypes (NRC37: high isoflavone; and NRC7: low isoflavone). Differential expression of MYB65-Gma-miR159, MYB96-Gma-miRNA1534, MYB176-Gma-miRNA5030, SPL9-Gma-miRNA156, TCP3, TCP4-Gma-miRNA319, WD40-Gma-miRNA162, UDP-glucose: flavonoid 3-O-glucosyltransferase-Gma-miRNA396, and CHI3-Gma-miRNA5434 showed an important relationship with their targets in both the soybean genotypes across all the stages. Therefore, the finding of the present work would certainly increase our understanding of molecular regulation of isoflavone biosynthetic pathway mediated by the miRNA which would guide molecular breeder to develop isoflavone rich soybean cultivars.

Cytosine Methylation of Isoflavone Synthase Gene in the Genic Region Positively Regulates Its Expression and Isoflavone Biosynthesis in Soybean Seeds

Plants, being sessile organisms, have evolved several dynamic mechanisms of gene regulation. Epigenetic modification especially cytosine methylation and demethylation actively regulates the expression of genes. To understand the role of cytosine methylation during isoflavonoid biosynthesis and accumulation, we performed cytosine methylation analysis in the coding region of two isoforms IFS1 and IFS2 gene, in two contrasting soybean genotypes differing in total isoflavone content (NRC37: high isoflavone; and NRC7: low isoflavone). The results indicated increased 5-mC in both the isoforms in NRC37 (∼20.51% in IFS2 and ∼85% in IFS1) compared with NRC7 (∼7.8% in IFS2 and ∼2.5% in IFS1) genotype, which signifies the positive role of 5-mC in the coding region of the gene leading to enhanced expression. In addition, temporal expression profiling [35 days after flowering (DAF), 45, 55, and 65 DAF] of both the isoforms showed increasing trend of accumulation in both the genotypes with maximum in NRC37 at 65 DAF. To further establish a correlation between methylation and expression of transcripts, we quantified the different isoforms of isoflavone in both the genotypes across all the stages. Therefore, the finding of this study would certainly increase our understanding of epigenetic regulation of isoflavone biosynthetic pathway mediated by the cytosine methylation that would assist molecular breeders to get high-performing soybean genotypes with better isoflavone yield.

Valorisation of black carrot pomace: microwave assisted extraction of bioactive phytoceuticals and antioxidant activity using Box-Behnken design

The present study compares three methods viz. microwave assisted extraction (MAE), ultrasonic-assisted extraction (UAE) and conventional solvent extraction (CSE) for extraction of phenolic compounds from black carrot pomace (BCP). BCP is the major by-product generated during processing and poses big disposal problem. Box-Behnken design using response surface methodology was employed to investigate and optimize the MAE of phenolics, antioxidant activity and colour density from BCP. The conditions for maximum recovery of polyphenolics were: microwave power (348.07 W), extraction time (9.8 min), solvent-solid ratio (19.3 mL/g) and ethanol concentration (19.8%). Under these conditions, the extract contained total phenolic content of 264.9 ± 10.02 mg gallic acid equivalents (GAE)/100 mL, antioxidant capacity (AOC) of 13.14 ± 1.05 µmol Trolox equivalents (TE)/mL and colour density of 68.63 ± 5.40 units. The total anthocyanin content at optimized condition was 753.40 ± 31.6 mg/L with low % polymeric colour of 7.40 ± 0.42. At optimized conditions, MAE yielded higher colour density (68.63 ± 5.40), polyphenolic content (264.9 ± 10.025 mg GAE/100 mL) and AOC (13.14 ± 1.05 µmol TE/mL) in a short time as compared to UAE and CSE. Overall results clearly indicate that MAE is the best suited method for extraction in comparison to UAE and CSE. The phenolic rich extract can be used as an effective functional ingredient in foods.

Molecular cloning and functional analysis of the promoter of γ-Tocopherol Methyl Transferase (γ-TMT) gene of soybean (Glycine max)

γ-Tocopherol methyl transferase (γ-TMT) (EC 2.1.1.95) is the key enzyme of the tocopherol biosynthetic pathway that determines the α-tocopherol concentration in plants. The overexpression of γ-TMT has been a successful approach for α-tocopherol enrichment of most plants including soybean. The typical soybean varieties are rich in γ-tocopherol (constitutes nearly 65-70% of its total seed tocopherol pool), while α-tocopherol, the biologically most active form among all tocopherols, constitutes only 10% of the total tocopherol content. The identification of soybean varieties that have seed α-tocopherol as high as > 20% of the total tocopherols has shifted attention towards the breeding based approach for α-tocopherol enrichment of this crop. Previous research on this aspect suggests that polymorphisms in γ-TMT promoter might be associated with the high α-tocopherol concentration of some soybean varieties. To understand the molecular basis of genetic variation for α-tocopherol concentration in Indian varieties of soybean we cloned the 1.4 kb upstream promoter region of γ-TMT from a high α-tocopherol containing soybean variety (Bragg) as well as from a low α-tocopherol containing variety (DS 2706). Cloning of each of these promoters in pORE R2 vector having GUS reporter gene and the subsequent GUS assay revealed a slightly high promoter activity of Bragg γ-TMT as compared to DS 2706 γ-TMT. On promoter sequence analysis, no sequence polymorphisms were observed in the core promoter region of this gene. However, seven single nucleotide polymorphisms (SNPs) were observed outside the core promoter region. Further study based on deletion construct analysis of this promoter will elucidate the significance of these SNPs in influencing the activity of γ-TMT promoter and the α-tocopherol concentration.

Development and Evaluation of Low Phytic Acid Soybean by siRNA Triggered Seed Specific Silencing of Inositol Polyphosphate 6-/3-/5-Kinase Gene

Soybean is one of the leading oilseed crop in the world and is showing a remarkable surge in its utilization in formulating animal feeds and supplements. Its dietary consumption, however, is incongruent with its existing industrial demand due to the presence of anti-nutritional factors in sufficiently large amounts. Phytic acid in particular raises concern as it causes a concomitant loss of indigestible complexed minerals and charged proteins in the waste and results in reduced mineral bioavailability in both livestock and humans. Reducing the seed phytate level thus seems indispensable to overcome the nutritional menace associated with soy grain consumption. In order to conceive our objective we designed and expressed a inositol polyphosphate 6-/3-/5-kinase gene-specific RNAi construct in the seeds of Pusa-16 soybean cultivar. We subsequently conducted a genotypic, phenotypic and biochemical analysis of the developed putative transgenic populations and found very low phytic acid levels, moderate accumulation of inorganic phosphate and elevated mineral content in some lines. These low phytic acid lines did not show any reduction in seedling emergence and displayed an overall good agronomic performance.

Enhanced nutraceutical potential of gamma irradiated black soybean extracts

Radiation processing of soybean, varying in seed coat colour, was carried out at dose levels of 0.25, 0.5 and 1 kGy to evaluate their potential anti-proliferative and cytoprotective effects in an in vitro cell culture system. Irradiated and control black (Kalitur) and yellow (DS9712) soybean extracts were characterized in terms of total phenolics, flavonoids and anthocyanins, especially cyanidin-3-glucoside (C3G). Using an epithelial cell line, BEAS-2B the potential cytoprotective effects of soybean extracts were evaluated in terms of intracellular ROS levels and cell viability. The most relevant scavenging effect was found in Kalitur, with 78% decrease in ROS, which well correlated with a 33% increase in C3G after a 1 kGy dose. Results evidenced a correspondence between in vitro antioxidant activity and a potential health property of black soybean extracts, exemplifying the nutraceutical role of C3G. To our knowledge this study is the first report validating the cytoprotective effects of irradiated black soybean extracts.

Exploring the role of Inositol 1,3,4-trisphosphate 5/6 kinase-2 (GmITPK2) as a dehydration and salinity stress regulator in Glycine max (L.) Merr. through heterologous expression in E. coli

Phytic acid (PA) is implicative in a spectrum of biochemical and physiological processes involved in plant stress response. Inositol 1,3,4, Tris phosphate 5/6 kinase (ITPK), a polyphosphate kinase that converts Inositol 1,3,4 trisphosphate to Inositol 1,3,4,5/6 tetra phosphate, averting the inositol phosphate pool towards PA biosynthesis, is a key regulator that exists in four different isoforms in soybean. In the present study, in-silico analysis of the promoter region of ITPKs was done and among the four isoforms, promoter region of GmITPK2 showed the presence of two MYB binding elements for drought inducibility and one for ABA response. Expression profiling through qRT-PCR under drought and salinity stress showed higher expression of GmITPK2 isoform compared to the other members of the family. The study revealed GmITPK2 as an early dehydration responsive gene which is also induced by dehydration and exogenous treatment with ABA. To evaluate the osmo-protective role of GmITPK2, attempts were made to assess the bacterial growth on Luria Broth media containing 200 mM NaCl, 16% PEG and 100 μM ABA, individually. The transformed E. coli BL21 (DE3) cells harbouring the GmITPK2 gene depicted better growth on the media compared to the bacterial cells containing the vector alone. Similarly, the growth of the transformed cells in the liquid media containing 200 mM NaCl, 16% PEG and 100 μM ABA showed higher absorbance at 600 nm compared to control, at different time intervals. The GmITPK2 recombinant E. coli cells showing tolerance to drought and salinity thus demonstrated the functional redundancy of the gene across taxa. The purity and specificity of the recombinant protein was assessed and confirmed through PAGE showing a band of ∼35 kDa on western blotting using Anti- Penta His- HRP conjugate antibody. To the best of our knowledge, the present study is the first report exemplifying the role of GmITPK2 isoform in drought and salinity tolerance in soybean.

Molecular modeling and in silico characterization of GmABCC5: a phytate transporter and potential target for low-phytate crops

Designing low-phytate crops without affecting the developmental process in plants had led to the identification of ABCC5 gene in soybean. The GmABCC5 gene was identified and a partial gene sequence was cloned from popular Indian soybean genotype Pusa16. Conserved domains and motifs unique to ABC transporters were identified in the 30 homologous sequences retrieved by BLASTP analysis. The homologs were analyzed for their evolutionary relationship and physiochemical properties. Conserved domains, transmembrane architecture and secondary structure of GmABCC5 were predicted with the aid of computational tools. Analysis identified 53 alpha helices and 31 beta strands, predicting 60% residues in alpha conformation. A three-dimensional (3D) model for GmABCC5 was developed based on 5twv.1.B (Homo sapiens) template homology to gain better insight into its molecular mechanism of transport and sequestration. Spatio-temporal real-time PCR analysis identified mid-to-late seed developmental stages as the time window for the maximum GmABCC5 gene expression, a potential target stage for phytate reduction. Results of this study provide valuable insights into the structural and functional characteristics of GmABCC5, which may be further utilized for the development of nutritionally enriched low-phytate soybean with improved mineral bioavailability.

Comparative Analysis of Tocopherol Biosynthesis Genes and Its Transcriptional Regulation in Soybean Seeds

Tocopherols composed of four isoforms (α, β, γ, and δ) and its biosynthesis comprises of three pathways: methylerythritol 4-phosphate (MEP), shikimate (SK) and tocopherol-core pathways regulated by 25 enzymes. To understand pathway regulatory mechanism at transcriptional level, gene expression profile of tocopherol-biosynthesis genes in two soybean genotypes was carried out, the results showed significantly differential expression of 5 genes: 1-deoxy-d-xylulose-5-P-reductoisomerase (DXR), geranyl geranyl reductase (GGDR) from MEP, arogenate dehydrogenase (TyrA), tyrosine aminotransferase (TAT) from SK and γ-tocopherol methyl transferase 3 (γ-TMT3) from tocopherol-core pathways. Expression data were further analyzed for total tocopherol (T-toc) and α-tocopherol (α-toc) content by coregulation network and gene clustering approaches, the results showed least and strong association of γ-TMT3/tocopherol cyclase (TC) and DXR/DXS, respectively, with gene clusters of tocopherol biosynthesis suggested the specific role of γ-TMT3/TC in determining tocopherol accumulation and intricacy of DXR/DXS genes in coordinating precursor pathways toward tocopherol biosynthesis in soybean seeds. Thus, the present study provides insight into the major role of these genes regulating the tocopherol synthesis in soybean seeds.

Molecular cloning, heterologous expression and functional characterization of gamma tocopherol methyl transferase (γ-TMT) from Glycine max

γ-Tocopherol methyltransferase (γ-TMT) (EC 2.1.1.95) is the last enzyme in the tocopherol biosynthetic pathway and it catalyzes the conversion of γ-tocopherol into α-tocopherol, the nutritionally significant and most bioactive form of vitamin E. Although the γ-TMT gene has been successfully overexpressed in many crops to enhance their α-tocopherol content but still only few attempts have been made to uncover its structural, functional and regulation aspects at protein level. In this study, we have cloned the complete 909bp coding sequence of Glycine max γ-TMT (Gm γ-TMT) gene that encodes the corresponding protein comprising of 302 amino acid residues. The deduced Gm γ-TMT protein showed 74-87% sequence identity with other characterized plant γ-TMTs. Gm γ-TMT belongs to Class I Methyl Transferases that have a Rossmann-like fold which consists of a seven-stranded β sheet joined by α helices. Heterologous expression of Gm γ-TMT in pET29a expression vector under the control of bacteriophage T7 promoter produced a 37.9 kDa recombinant Gm γ-TMT protein with histidine hexamer tag at its C-terminus. The expression of recombinant Gm γ-TMT protein was confirmed by western blotting using anti-His antibody. The recombinant protein was purified by Ni2+-NTA column chromatography. The purified protein showed SAM dependent methyltransferase activity. The α-tocopherol produced in the in-vitro reaction catalyzed by the purified enzyme was detected using reverse phase HPLC. This study has laid the foundation to unveil the biochemical understanding of Gm γ-TMT enzyme which can be further explored by studying its kinetic behaviour, substrate specificity and its interaction with other biomolecules.

RNA Interference: A Novel Source of Resistance to Combat Plant Parasitic Nematodes

Plant parasitic nematodes cause severe damage and yield loss in major crops all over the world. Available control strategies include use of insecticides/nematicides but these have proved detrimental to the environment, while other strategies like crop rotation and resistant cultivars have serious limitations. This scenario provides an opportunity for the utilization of technological advances like RNA interference (RNAi) to engineer resistance against these devastating parasites. First demonstrated in the model free living nematode, Caenorhabtidis elegans; the phenomenon of RNAi has been successfully used to suppress essential genes of plant parasitic nematodes involved in parasitism, nematode development and mRNA metabolism. Synthetic neurotransmitants mixed with dsRNA solutions are used for in vitro RNAi in plant parasitic nematodes with significant success. However, host delivered in planta RNAi has proved to be a pioneering phenomenon to deliver dsRNAs to feeding nematodes and silence the target genes to achieve resistance. Highly enriched genomic databases are exploited to limit off target effects and ensure sequence specific silencing. Technological advances like gene stacking and use of nematode inducible and tissue specific promoters can further enhance the utility of RNAi based transgenics against plant parasitic nematodes.

Regulation of Isoflavone Biosynthesis by miRNAs in Two Contrasting Soybean Genotypes at Different Seed Developmental Stages

Owing to the presence of nutritionally important, health-promoting bioactive compounds, especially isoflavones, soybean has acquired the status of a functional food. miRNAs are tiny riboregulator of gene expression by either decreasing and/or increasing the expression of their corresponding target genes. Despite several works on identification and functional characterization of plant miRNAs, the role of miRNAs in the regulation of isoflavones metabolism is still a virgin field. In the present study, we identified a total of 31 new miRNAs along with their 245 putative target genes from soybean seed-specific ESTs using computational approach. The Kyoto Encyclopedia of Genes and Genomes pathway analyses indicated that miRNA putatively regulates metabolism and genetic information processing. Out of that, a total of 5 miRNAs (Gma-miRNA12, Gma-miRNA24, Gma-miRNA26, Gma-miRNA28, and Gma-miRNA29) were predicted and validated for their probable role during isoflavone biosynthesis. We also validated their five target genes using RA-PCR, which is as good as 5'RLM-RACE. Temporal regulation [35 days after flowering, 45, 55, and 65 DAF] of miRNAs and their targets showed differential expression schema. Differential expression of Gma-miR26 and Gma-miRNA28 along with their corresponding target genes (Glyma.10G197900 and Glyma.09G127200) showed a direct relationship with the total isoflavone content. Therefore, understanding the miRNA-based genetic regulation of isoflavone pathway would assist in selection and manipulation to get high-performing soybean genotypes with better isoflavone yield.

Genomic organization, phylogenetic comparison, and expression profiles of the SPL family genes and their regulation in soybean

SQUAMOSA Promoter-Binding Protein-Like (SPL) genes form a major family of plant-specific transcription factors and play an important role in plant growth and development. In this study, we report the identification of 41 SPL genes (GmSPLs) in the soybean genome. Phylogenetic analysis revealed that these genes were divided into five groups (groups 1-5). Further, exon/intron structure and motif composition revealed that the GmSPL genes are conserved within their same group. The N-terminal zinc finger 1 (Zn1) of the SBP domain was a CCCH (Cys3His1) and the C terminus zinc finger 2 (Zn2) was a CCHC (Cys2HisCys) type. The 41 GmSPL genes were distributed unevenly on 17 of the 20 chromosomes, with tandem and segmental duplication events. We found that segmental duplication has made an important contribution to soybean SPL gene family expansion. The Ka/Ks ratios revealed that the duplicated GmSPL genes evolved under the effect of purifying selection. In addition, 17 of the 41 GmSPLs were found as targets of miR156; these might be involved in their posttranscriptional regulation through miR156. Importantly, RLM-RACE analysis confirmed the GmmiR156-mediated cleavage of GmSPL2a transcript in 2-4 mm stage of soybean seed. Alternative splicing events in 9 GmSPLs were detected which produces transcripts and proteins of different lengths that may modulate protein signaling, binding, localization, stability, and other properties. Expression analysis of the soybean SPL genes in various tissues and different developmental stages of seed suggested distinct spatiotemporal patterns. Differences in the expression patterns of miR156-targeted and miR156-non-targeted soybean SPL genes suggest that miR156 plays key functions in soybean development. Our results provide an important foundation for further uncovering the crucial roles of GmSPLs in the development of soybean and other biological processes.

Salinity-induced inhibition of growth in the aquatic pteridophyte Azolla microphylla primarily involves inhibition of photosynthetic components and signaling molecules as revealed by proteome analysis

Salinity stress causes adverse physiological and biochemical changes in the growth and productivity of a plant. Azolla, a symbiotic pteridophyte and potent candidate for biofertilizer due to its nitrogen fixation ability, shows reduced growth and nitrogen fixation during saline stress. To better understand regulatory components involved in salinity-induced physiological changes, in the present study, Azolla microphylla plants were exposed to NaCl (6.74 and 8.61 ds/m) and growth, photochemical reactions of photosynthesis, ion accumulation, and changes in cellular proteome were studied. Maximum dry weight was accumulated in control and untreated plant while a substantial decrease in dry weight was observed in the plants exposed to salinity. Exposure of the organism to different concentrations of salt in hydroponic conditions resulted in differential level of Na⁺ and K⁺ ion accumulation. Comparative analysis of salinity-induced proteome changes in A. microphylla revealed 58 salt responsive proteins which were differentially expressed during the salt exposure. Moreover, 42 % spots among differentially expressed proteins were involved in different signaling events. The identified proteins are involved in photosynthesis, energy metabolism, amino acid biosynthesis, protein synthesis, and defense. Downregulation of these key metabolic proteins appears to inhibit the growth of A. microphylla in response to salinity. Altogether, the study revealed that in Azolla, increased salinity primarily affected signaling and photosynthesis that in turn leads to reduced biomass.

Contemporary Understanding of miRNA-Based Regulation of Secondary Metabolites Biosynthesis in Plants

Plant's secondary metabolites such as flavonoids, terpenoids, and alkaloids etc. are known for their role in the defense against various insects-pests of plants and for medicinal benefits in human. Due to the immense biological importance of these phytochemicals, understanding the regulation of their biosynthetic pathway is crucial. In the recent past, advancement in the molecular technologies has enabled us to better understand the proteins, enzymes, genes, etc. involved in the biosynthetic pathway of the secondary metabolites. miRNAs are magical, tiny, non-coding ribonucleotides that function as critical regulators of gene expression in eukaryotes. Despite the accumulated knowledge of the miRNA-mediated regulation of several processes, the involvement of miRNAs in regulating secondary plant product biosynthesis is still poorly understood. Here, we summarize the recent progress made in the area of identification and characterizations of miRNAs involved in regulating the biosynthesis of secondary metabolites in plants and discuss the future perspectives for designing the viable strategies for their targeted manipulation.

Refined glufosinate selection and its extent of exposure for improving the Agrobacterium-mediated transformation in Indian soybean (Glycine max) genotype JS-335

Soybean like many other crops, in this genomic era, has well-established genomic database which provides a wide range of opportunities for improvement through genetic manipulation. But the growing demand for soybean transgenics with increased production and improved quality has been handicapped due to inefficient transformation strategies and hence an efficient, stable and reliable transformation system is of prime requisite. In the present study, Agrobacterium-mediated transformation was standardized by refining the glufosinate selection system in terms of dosage (0-6 mg l^-1) and degree of exposure. The cotyledonary node explants (with and without wounding) initially cultured on a non-selective shoot induction medium for 10 days before transferring them to the selective SIM with an optimized concentration of 5.0 mg l^-1 ammonium glufosinate, showed least selection escape frequency. Wounded cotyledonary node explants infected with Agrobacterium tumefaciens harboring pBIN-bar construct, showed an improved regeneration efficiency of 55.10% and transformation efficiency of 12.6% using Southern blotting in T₁ plants. Southern analysis of T₁ plants confirmed the integration of bar gene into the genomic DNA and the bar positive T₁ plants segregated in 3 : 1 ratio. This is the first report, to our knowledge, of a high transformation efficiency using Agrobacterium-mediated cot node-glufosinate system in an Indian soybean genotype.

Elucidation of the role of oleosin in off-flavour generation in soymeal through supercritical CO₂ and biotic elicitor treatments

Defatting soybean by sophisticated oil extraction method utilising supercritical CO2 resulted in a significant decrease in the residual phospholipids (PLs) compared with soymeal obtained by conventional cold percolation method utilising hexane as the extraction solvent. Interestingly, the levels of residual PLs showed a proportionate relationship with thiobarbituric acid (TBA) number, an indicator of lipid peroxidation responsible for off-flavour generation. Furthermore, two oleosins (18 and 24 kDa) were isolated from the oil bodies extracted from soybean seeds and positively characterised for phospholipase A2 (PLA2) activity, suggesting their plausible involvement in off-flavour generation in soymeal. The treatment of soybean seeds, before oil extraction, with different concentrations of biotic elicitors such as chitosan and jasmonic acid also significantly reduced the levels of residual PLs as well as the TBA number. The biotic elicitor treatment could thus prove to be an important strategy for the reduction of off-flavour in protein-rich soymeal.

Role of phytosterols in drought stress tolerance in rice

Phytosterols are integral components of the membrane lipid bilayer in plants. They regulate membrane fluidity to influence its properties, functions and structure. An increase in accumulation of phytosterols namely campesterol, stigmasterol and β-sitosterol was observed in rice as seedlings matured. The levels of the major phytosterol, β-sitosterol in N22 (drought tolerant) rice seedlings was found to increase proportionately with severity of drought stress. Its levels were 145, 216, 345 and 364 μg/g FW after subjecting to water stress for 3, 6, 9 and 12 days respectively, while for IR64 (drought susceptible), levels were 137, 198, 227 and 287 μg/g FW at the same stages. Phytosterols were also found to increase with maturity as observed at 30, 50 and 75 days after planting. The activity of HMG-CoA reductase (EC 1.1.1.34) which is considered to be a key limiting enzyme in the biosynthesis of phytosterols was 0.55, 0.56, 0.78 and 0.85 μmol/min/L at 3, 6, 9 and 12 days of water stress in N22 and 0.31, 0.50, 0.54 and 0.65 μmol/min/L in case of IR64 respectively. The elevation in the levels of phytosterols as well as the activity of HMG-CoA reductase during drought stress indicates the role of phytosterols in providing tolerance to stress.

Changes in the levels of off-flavor generation in soybean through biotic elicitor treatments

The nutritional benefits of soybean remain underutilized as the off-flavor present in it limits the consumption and acceptability among people. The aim of the present study was to unveil the effect of the phytohormones methyl jasmonate (MJ: 0, 50 μM, 1 mM, and 15 mM) and salicylic acid (SA: 0, 50 μM, 0.1 mM, and 10 mM) as elicitors on two contrasting off-flavor soybean varieties at different growth stages (1, bloom; 2, pod development; 3, seed development). The effects of two elicitors varied widely and were found to be dose dependent and growth stage independent. SA reduces the lipoxygenase (LOX) and hydroperoxide lyase (HPL) activity, which in turn resulted in reduction in the TBA number and carbonyl value in contrast to MJ. SA 0.1 mM is the most effective dose in reduction of off-flavor determining parameters and protein oxidation, and it reduces the LOX and HPL activity by 2.3- and 2.4-fold, respectively in "high off-flavor" cultivar 'Bragg' compared to "low off-flavor" cultivar 'DS 2706' which showed 1.4- and 2.1-fold, respectively. This reduction in protein oxidation is also supported by enhanced content of antioxidant enzymes. Thus, phytohormone SA can be used in reduction of off-flavor generation, more effectively than MJ treatments, in soybean.

Isolated tuberculosis of talus: a case report

Tuberculosis still remains a leading infection, causing death and disability worldwide. We report a patient with isolated tuberculosis of the talus bone. A 14 year old boy reported with an eight-month history of swelling and pain in his left ankle joint. Routine investigations indicated positive aetiology of tuberculous infection . Surgical curettage of the talus and, debridement were performed and a below knee POP cast was applied along with anti TB therapy. After 18 months postoperative , the patient was able to carry out his daily activities without pain .The ankle and foot are rarely affected and account for only 1% of all TB infections. Provisional diagnosis can be made through history and routine investigations but confirmation by the identification of the bacillus from the local lesion or by a histopathological examination of tissue. Talus tuberculosis should be considered in any long standing inflammatory pathology of the ankle.

In vitro kinetics of soybean lipoxygenase with combinatorial fatty substrates and its functional significance in off flavour development

Lipoxygenase (Lox) mediated oxidation of polyunsaturated fatty acids (PUFA) in mature soya seeds results in objectionable flavour. In the present study, Lox isozymes were purified to near homogeneity (107-fold). Lox-2 and 3 displayed remarkable kinetic preference (1.7 and 1.5-fold, respectively) for low PUFA ratios (LA/LeA) (PRs) among the selected PUFA combinations. Lox-1 displayed no specific preference. Pure Lox-1 displayed unbiased response towards substrates with marginal preference (1.2-fold) for linoleic acid at its optimum pH. Volatile compounds profiling showed a direct relationship between PRs and hexanal to trans-2-hexenal (1.47, 2.24 and 18.90 for 2, 7 and 15 PRs, respectively) ratio. The off-flavour determining parameters like TBA value, carbonyl value and lipid hydroperoxides (LHPODs) exhibited significant negative correlation (0.76, 0.74, 0.72; p<0.0001) in selected soya genotypes displaying varied PRs and significant positive correlation (0.89, 0.81. 0.89; p<0.0001) with ratio of PI (polyene index) to PRs - suggesting the plausible significance of PUFA ratios in biological lipid peroxidation.

Role of gamma-oryzanol in drought-tolerant and susceptible cultivars of rice (Oryza sativa L.)

Drought-tolerant cultivars and their phytochemical composition, which has a role in providing drought tolerance are gaining importance. In this study, rice bran oil and semi-purified oryzanol (SPO) obtained from five rice (Oryza sativa L.) cultivars, namely P1401 and PB1 (drought-susceptible) and N22, PNR381 and APO (drought-tolerant) were analyzed for the gamma-oryzanol content, an antioxidant present in considerable amount in the rice bran. The higher level of gamma-oryzanol and its antioxidant activity was observed in drought-tolerant cultivars (N22, PNR381 and APO) as compared to drought-susceptible (PB1 and P1401), suggesting the role of gamma-oryzanol in drought tolerance, as antioxidants are known to play an important role by scavenging free radicals. The total antioxidant activity of gamma-oryzanol might be attributed to 24-methylene cycloartanyl ferulate, a major component of gamma-oryzanol. By enhancing the level of active oryzanol components identified in this study by genetic and molecular means could impart increased drought tolerance.