Lathyrus sativus (grass pea) and its neurotoxin ODAP

The Potential of CRISPR/Cas9 to Circumvent the Risk Factor Neurotoxin β-N-oxalyl-L-α, β-diaminopropionic acid Limiting Wide Acceptance of the Underutilized Grass Pea (Lathyrus sativus L.)

Grass pea (Lathyrus sativus L.) is a protein-rich crop that is resilient to various abiotic stresses, including drought. However, it is not cultivated widely for human consumption due to the neurotoxin β-N-oxalyl-L-α, β-diaminopropionic acid (β-ODAP) and its association with neurolathyrism. Though some varieties with low β-ODAP have been developed through classical breeding, the β-ODAP content is increasing due to genotype x environment interactions. This review covers grass pea nutritional quality, β-ODAP biosynthesis, mechanism of paralysis, traditional ways to reduce β-ODAP, candidate genes for boosting sulfur-containing amino acids, and the potential and targets of gene editing to reduce β-ODAP content. Recently, two key enzymes (β-ODAP synthase and β-cyanoalanine synthase) have been identified in the biosynthetic pathway of β-ODAP. We proposed four strategies through which the genes encoding these enzymes can be targeted and suppressed using CRISPR/Cas9 gene editing. Compared to its homology in Medicago truncatula, the grass pea β-ODAP synthase gene sequence and β-cyanoalanine synthase showed 62.9% and 95% similarity, respectively. The β-ODAP synthase converts the final intermediate L-DAPA into toxic β-ODAP, whist β-cyanoalanine synthase converts O-Acetylserine into β-isoxazolin-5-on-2-yl-alanine. Since grass pea is low in methionine and cysteine amino acids, improvement of these amino acids is also needed to boost its protein content. This review contains useful resources for grass pea improvement while also offering potential gene editing strategies to lower β-ODAP levels.

Scenario on Production, Processing, and Utilization of Grasspea (Lathyrus sativus L.) in Agromarginal Geographies and Its Future Prospects

Grasspeas are environmentally successful and robust legumes with major traits of interest for food and nutrition security. It is a critical crop in areas prone to drought, overmoisture stress, and famine, hence, regarded as an "insurance crop" because of its inherent resilience of climatic calamities. The current status and prospects of grasspea, as well as various breeding and food processing approaches to improve this crop for integration in diverse and sustainable agrifood systems, are discussed in this review. Grasspeas are often the source of important micronutrients and proteins (18%-34%), saving peoples' lives during famine. Grasspea consumption is increasing in some countries; however, uninterrupted consumption of grasspea should be avoided, especially when they are green or unripe and when they are raw. Effective food processing techniques are essential to reduce the neurotoxic hazards associated with eating grasspea. Several effective processing steps can be used to reduce toxicity in addition to the development of toxin-free varieties for production and consumption. With advances in the scientific investigation of the grasspea, integration of genetics, processing, and behavioral components has been suggested.

Prevalence of major depressive disorder and its associated factors among adult patients with neurolathyrism in Dawunt District, Ethiopia; 2022: community-based cross-sectional study

INTRODUCTION

Major Depressive Disorder (MDD) is one of the commonest mental disorders affecting more than 250 million people globally. Patients with chronic illnesses had higher risks for developing MDD than the general population. Neurolathyrism is a chronic illness characterized by lifelong incurable spastic paralysis of lower extremities; causing permanent disability. It is highly prevalent in Dawunt district, Ethiopia; with a point prevalence of 2.4%. Despite this, there were no previous studies assessing the prevalence of MDD among patients with neurolathyrism in Ethiopia.

OBJECTIVE

To assess the prevalence of MDD and to identify its associated factors among patients with neurolathyrism in Dawunt district, Ethiopia.

METHODS

A community based cross-sectional study was conducted on 260 samples in Dawunt district from February 01 to March 30/ 2021. Multistage sampling technique was used to select study participants. The patient Health Questionnaire-9 (PHQ-9) depression screening tool was used to diagnose MDD. PHQ-9 is a standardized depression screening tool and a PHQ-9 score of ≥ 10 has a sensitivity and specificity of 88.0% [95% CI (83.0-92.0%)] and 85.0% [95% CI (82.0-88.0%)] for screening MDD. Data were collected by interview; entered to EpiData version 4.2.0; exported to SPSS version 25.0 for analysis; descriptive statistics and binary logistic regression model were used; AOR with 95% CI was used to interpret the associations; and finally results were presented by texts, charts, graphs, and tables.

RESULTS

A total of 256 adult patients with neurolathyrism were participated; and the prevalence of MDD was found to be 38.7%. Being female [AOR = 3.00; 95% CI (1.15, 7.84)], living alone [AOR = 2.77; 95% CI (1.02-7.53)], being on neurolathyrism stage-3 [AOR = 3.22; 95% CI (1.09, 9.54)] or stage-4 [AOR = 4.00; 95% CI (1.28, 12.48)], stigma [AOR = 2.69; 95% CI (1.34, 5.39)], and lack of social/ family support [AOR = 3.61; 95% CI (1.80, 7.24)] were found to have statistically significant association with an increased odds of MDD; while regular exercise and ever formal counselling were found to have statistically significant association with a decreased odds of MDD.

CONCLUSION

The prevalence of MDD among neurolathyrism patients in Dawunt district was high. Lack of social support, stigma, not getting formal counselling, and not involving in regular exercise were modifiable risk factors. Therefore, social support, reducing stigma, formal counselling, and encouraging regular exercise might help to reduce the burden of MDD among neurolathyrism patients.

Prevalence of Neurolathyrism and its associated factors in Grass pea cultivation areas of Dawunt District, North-eastern Ethiopia; 2022: a community based multilevel analysis

INTRODUCTION

Neurolathyrism is an upper motor neuron disorder characterized by spastic paraparesis, which is caused by the prolonged over-consumption of grass pea. It is a devastating disease with great impacts on physical, social, mental, and economical health.

OBJECTIVE

To determine the prevalence of neurolathyrism and its associated factors in grass pea cultivation areas of Dawunt wereda.

METHODS

Community based cross-sectional study design was conducted from February 01- March 30, 2021 on 631 Households with a total of 3,350 individuals. Two-stage random sampling technique was used to select participants. Multilevel binary logistic regression was used to identify factors associated with neurolathyrism. Statistical significance was declared at p < 0.05; and AOR with 95% CI was used to interpret the results.

RESULTS

The household and population level prevalence of neurolathyrism in Dawunt district were 9.2% (7.2-11.7%) and 2.4% (2.0-2.3.0%) respectively. Age (AOR = 7.4 ( 2.6-20.6)), male sex (AOR = 7.8 (3.9, 15.4)), and marital status (AOR = 4.0 (1.3-12.8)) were the individual level variables; family size (AOR = 12.6 (3.0-52.8)), annual grass pea production (AOR = 5.0 (2.3-11.0)), ever feeding only grass pea (AOR = 8.8(3.5-22.2)), ever feeding immature seeds of grass pea (AOR = 6.28 (2.80, 14.08)), high grass pea to other cereals mixing ratio (> 3:1) (AOR = 6.1 (1.1, 33.5)) were the household level variables found to have significant association with neurolathyrism.

CONCLUSION

The prevalence of neurolathyrism was found to be high. Ever feeding only grass pea, Grass pea to other cereals mixing ratio (using ratio of 1:1 or more), and Ever feeding immature grass pea seeds were the modifiable risk factors for neurolathyrism.

Lathyrism in Spain: Lessons from 68 publications following the 1936-39 Civil War

After the end of the Spanish Civil War (1936-1939), an estimated 1,000 patients presented with lathyrism due to their excessive and prolonged consumption of grasspea (Lathyrus sativus L.) against the backdrop of poverty, drought, and famine. Based on 68 scientific communications between 1941 and 1962 by qualified medical professionals, the disease emerged in different geographical locations involving selective populations: (1) farmers from extensive areas of central Spain, traditionally producers and consumers of grasspea; (2) immigrants in the industrial belt of Catalonia and in the Basque Country, areas with little or no production of grasspea, which was imported from producing areas; (3) workers in Galicia, an area where the legume is neither produced nor consumed, who were seasonally displaced to high-production areas of grasspea in Castille; and (4) inmates of overcrowded postwar Spanish prisons. Original reports included failed attempts by Carlos Jiménez Díaz (1898-1967) to induce experimental lathyrism, the neuropathology of lathyrism in early stages of the disease in two patients, as reported by Carlos Oliveras de la Riva (1914-2007), and the special susceptibility of children to develop a severe form of lathyrism after relatively brief periods of consumption of the neurotoxic seed of L. sativus. In the Spanish Basque Country, L. cicera L. (aizkol) was cultivated exclusively as animal fodder. Patients who were forced to feed on this plant developed unusual manifestations of lathyrism, such as axial myoclonus and severe neuropsychiatric disorders, unknown in other regions of the country and previously unreported. The postwar epidemic of lathyrism in Spain represents the most extensively studied outbreak of this self-limiting but crippling upper motor neuron disease.

Determination of Dencichine in Panax notoginseng in the Forest and Field Using High Performance Liquid Chromatography

Dencichine is a nonprotein amino acid, an effective ingredient in Panax notoginseng with hemostatic and anti-inflammatory effects. There are few studies on the effects of regions and cultivation models on the accumulation of dencichine. In the current study, the content of dencichine in P. notoginseng collected from its global cultivation and trading center Yunnan, China, (>640 samples) was determined using an optimized high-performance liquid chromatography method coupled with a diode array detector but without derivatization. The recovery rate of this method was 80-110%, the relative standard deviation was <10%, and the limits of detection and quantification were 0.003% (w/w) and 0.01% (w/w), respectively. The content of dencichine in each part of P. notoginseng was as follows: rootlets (39.59%) > main roots (29.91%) > leaves (16.21%) > stems (14.29%). For leaves, P. notoginseng in the forest (5.52 ± 2.26 mg/g) was significantly higher than that in the field (3.93 ± 1.72 mg/g) but opposite for main roots. The origins and altitudes made different contributions to the accumulation of dencichine in P. notoginseng. This study provides an effective analytical method to determine dencichines in various parts of P. notoginseng from different origins and altitudes and supports quality control and product development of P. notoginseng.

Identification, characterization, and validation of NBS-encoding genes in grass pea

Grass pea is a promising crop with the potential to provide food and fodder, but its genomics has not been adequately explored. Identifying genes for desirable traits, such as drought tolerance and disease resistance, is critical for improving the plant. Grass pea currently lacks known R-genes, including the nucleotide-binding site-leucine-rich repeat (NBS-LRR) gene family, which plays a key role in protecting the plant from biotic and abiotic stresses. In our study, we used the recently published grass pea genome and available transcriptomic data to identify 274 NBS-LRR genes. The evolutionary relationships between the classified genes on the reported plants and LsNBS revealed that 124 genes have TNL domains, while 150 genes have CNL domains. All genes contained exons, ranging from 1 to 7. Ten conserved motifs with lengths ranging from 16 to 30 amino acids were identified. We found TIR-domain-containing genes in 132 LsNBSs, with 63 TIR-1 and 69 TIR-2, and RX-CCLike in 84 LsNBSs. We also identified several popular motifs, including P-loop, Uup, kinase-GTPase, ABC, ChvD, CDC6, Rnase_H, Smc, CDC48, and SpoVK. According to the gene enrichment analysis, the identified genes undergo several biological processes such as plant defense, innate immunity, hydrolase activity, and DNA binding. In the upstream regions, 103 transcription factors were identified that govern the transcription of nearby genes affecting the plant excretion of salicylic acid, methyl jasmonate, ethylene, and abscisic acid. According to RNA-Seq expression analysis, 85% of the encoded genes have high expression levels. Nine LsNBS genes were selected for qPCR under salt stress conditions. The majority of the genes showed upregulation at 50 and 200 μM NaCl. However, LsNBS-D18, LsNBS-D204, and LsNBS-D180 showed reduced or drastic downregulation compared to their respective expression levels, providing further insights into the potential functions of LsNBSs under salt stress conditions. They provide valuable insights into the potential functions of LsNBSs under salt stress conditions. Our findings also shed light on the evolution and classification of NBS-LRR genes in legumes, highlighting the potential of grass pea. Further research could focus on the functional analysis of these genes, and their potential use in breeding programs to improve the salinity, drought, and disease resistance of this important crop.

Exploiting genetic and genomic resources to enhance productivity and abiotic stress adaptation of underutilized pulses

Underutilized pulses and their wild relatives are typically stress tolerant and their seeds are packed with protein, fibers, minerals, vitamins, and phytochemicals. The consumption of such nutritionally dense legumes together with cereal-based food may promote global food and nutritional security. However, such species are deficient in a few or several desirable domestication traits thereby reducing their agronomic value, requiring further genetic enhancement for developing productive, nutritionally dense, and climate resilient cultivars. This review article considers 13 underutilized pulses and focuses on their germplasm holdings, diversity, crop-wild-crop gene flow, genome sequencing, syntenic relationships, the potential for breeding and transgenic manipulation, and the genetics of agronomic and stress tolerance traits. Recent progress has shown the potential for crop improvement and food security, for example, the genetic basis of stem determinacy and fragrance in moth bean and rice bean, multiple abiotic stress tolerant traits in horse gram and tepary bean, bruchid resistance in lima bean, low neurotoxin in grass pea, and photoperiod induced flowering and anthocyanin accumulation in adzuki bean have been investigated. Advances in introgression breeding to develop elite genetic stocks of grass pea with low β-ODAP (neurotoxin compound), resistance to Mungbean yellow mosaic India virus in black gram using rice bean, and abiotic stress adaptation in common bean, using genes from tepary bean have been carried out. This highlights their potential in wider breeding programs to introduce such traits in locally adapted cultivars. The potential of de-domestication or feralization in the evolution of new variants in these crops are also highlighted.

Diamine Oxidase as a Therapeutic Enzyme: Study of Germination from Vegetal Sources and Investigation of the Presence of β-N-Oxalyl-L-α,β-diaminopropionic Acid (β-ODAP) Using LC-MS/MS

Vegetal diamine oxidase (vDAO), an enzyme proposed to relieve symptoms of histaminosis, shows better reactivity with histamine and aliphatic diamines, as well as higher enzymatic activity than DAO of animal origin. The objective of this study was to evaluate the enzyme activity of vDAO from germinating grains from Lathyrus sativus (grass pea) and Pisum sativum (pea), and to verify the presence of a neurotoxin, β-N-Oxalyl-L-α,β-diaminopropionic acid (β-ODAP), in the crude extract obtained from their seedlings. A targeted liquid chromatography-multiple-reaction monitoring mass spectrometry method was developed and used to quantify β-ODAP in the analysed extracts. An optimized sample preparation procedure, involving protein precipitation with acetonitrile followed by mixed-anion exchange solid-phase extraction, allowed for high sensitivity and good peak shape for β-ODAP detection. The Lathyrus sativus extract exhibited the highest vDAO enzyme activity of the extracts, followed by the extract from pea cultivar Amarillo from the Crop Development Centre (CDC). The results have also shown that even though β-ODAP was present in the crude extract from L. sativus, its content was far below the toxicity threshold (300 mg of β-ODAP/kg body/day). CDC Amarillo showed 5000-fold less β-ODAP than the undialysed L. sativus extract. It was concluded that both species can be considered as convenient sources of vDAO for potential therapeutic use.

Genomics and biochemical analyses reveal a metabolon key to β-L-ODAP biosynthesis in Lathyrus sativus

Grass pea (Lathyrus sativus L.) is a rich source of protein cultivated as an insurance crop in Ethiopia, Eritrea, India, Bangladesh, and Nepal. Its resilience to both drought and flooding makes it a promising crop for ensuring food security in a changing climate. The lack of genetic resources and the crop's association with the disease neurolathyrism have limited the cultivation of grass pea. Here, we present an annotated, long read-based assembly of the 6.5 Gbp L. sativus genome. Using this genome sequence, we have elucidated the biosynthetic pathway leading to the formation of the neurotoxin, β-L-oxalyl-2,3-diaminopropionic acid (β-L-ODAP). The final reaction of the pathway depends on an interaction between L. sativus acyl-activating enzyme 3 (LsAAE3) and a BAHD-acyltransferase (LsBOS) that form a metabolon activated by CoA to produce β-L-ODAP. This provides valuable insight into the best approaches for developing varieties which produce substantially less toxin.

Field phenotyping and quality traits of grass pea genotypes in South Italy

BACKGROUND

Grass pea (Laithyrus sativus L.) is a rustic plant whose seeds are rich in polyphenols and antioxidants, and it has been consumed as food by human beings since ancient times. This study was conducted in Italy between 2017and 2019 to evaluate, under field conditions, the stability of seed yield, biomass and 1000-seed weight (THS) and to assess the antioxidant composition and activity of 11 grass pea accessions.

RESULTS

Analysis of variance revealed significant effects of the environment, accession and accession × environment (A × E) on the yield, above-ground biomass and THS. We found that the environment (year) and A × E explained 52.61% and 23.76% of the total seed yield variation, respectively. No relationship was observed between the yield and the total protein of seeds. Most grass pea accessions showed sensitivity to frost conditions that occurred in the third growing season. The total phenolic content ranged from 50.51 to 112.78 mg 100 g-1 seeds and antioxidant activity ranged from 0.576 to 0.898 mmol Trolox equivalents 100 g-1 seeds and from 0.91 to 1.6 mmol Fe2+  100 g-1 seeds in 2,20-azinobis-3-ethylbenzothiazoline-6-sulfonic acid and ferric-reducing antioxidant power, respectively. Among the accessions, the 'Campi Flegrei' and 'di Castelcività' showed the best performance with the highest yield and stability, phenolic content and superior antioxidant activity.

CONCLUSION

The results showed that the yield of grass pea was mainly influenced by different climate conditions. This variability in yield, phenolic content and antioxidant activity among different accessions could help breeders and farmers select high-performance accessions for cultivation. © 2020 Society of Chemical Industry.

Construction of A GBS-Based High-Density Genetic Map and Flower Color-Related Loci Mapping in Grasspea (Lathyrus sativus L.)

Grasspea (Lathyrus sativus L.), a legume crop with excellent resistance to a broad array of environmental stressors, has, to this point, been poorly genetically characterized. High-density genetic linkage maps are critical for draft genome assembly, quantitative trait loci (QTLs) analysis, and gene mining. The lack of a high-density genetic linkage map has limited both genomic studies and selective breeding in grasspea. Here, we developed a high-density genetic linkage map of grasspea using genotyping-by-sequencing (GBS) to sequence 154 grasspea plants, comprising 2 parents and 152 F2 progeny. In all, 307.74 Gb of data was produced, including 2,108,910,938 paired-end reads, as well as 3536 SNPs mapped to seven linkage groups (LG1–LG7). With an average length of 996.52 cM per LG, the overall genetic distance was 6975.68 cM. Both the χ2 test and QTL analysis, based on the Kruskal–Wallis (KW) test and interval mapping (IM) analysis, revealed the monogenic inheritance of flower color in grasspea, with the responsible QTL located between 308.437 cM and 311.346 cM in LG4. The results can aid grasspea genome assembly and accelerate the selective breeding of new grasspea germplasm resources.

Neurotoxin (N-Oxalyl-L-α,β-Diamino Propionic Acid) Content in Different Plant Parts of Grass Pea (Lathyrus sativus L.) Spanning Seedling to Maturity Stage: Does It Increase over Time?

ODAP (N-oxalyl-L-2,3-diaminopropionic acid) is present in the seeds of grass pea. In this study, variation of total ODAP accumulation in leaves throughout the crop growth starting from 40 days after sowing to maturity, and the distribution pattern of ODAP in different plant parts including the seeds at the mature stage was analyzed. Five grass pea accessions were evaluated for two subsequent growing seasons in one location of ICARDA, Aleppo (Syria). The results found that the rate of accumulation of total ODAP varied during plant development. Increased rates of synthesis were noticed in young leaves of grass pea. The highest total ODAP content in leaves was noted in the early growth stage (40-50 days after sowing). Mean total ODAP content in leaves ranged from 0.17 to 0.96 percent during 2010-2011 and from 0.19 to 1.28 percent during 2011-2012. During maturity, the total ODAP content was lowest in the seeds than in leaves, stems, pod cover, seed coat, and cotyledons. The ranges of total ODAP content were 0.13 (seed)-0.34 (stem), 0.20 (seed)-1.01 (leaf), 0.22 (seed)-0.62 (leaf), 0.21 (seed)-0.66 (leaf), and 0.21 (seed)-0.78 (leaf) percent in B387, B222, B390, Bio-520, and B587 accessions, respectively, during maturity. The results indicated that the rate of accumulation and synthesis of total ODAP varied during the plant lifespan. The lowest total ODAP content of leaves was observed after 130 days of sowing. The lower total ODAP content after the early vegetative stage of grass pea plants makes them suitable as a feed.

Identification and characterization of the key enzyme in the biosynthesis of the neurotoxin β-ODAP in grass pea

Grass pea (Lathyrus sativus L.) is a grain legume commonly grown in Asia and Africa for food and forage. It is a highly nutritious and robust crop, capable of surviving both droughts and floods. However, it produces a neurotoxic compound, β-N-oxalyl-L-α,β-diaminopropionic acid (β-ODAP), which can cause a severe neurological disorder when consumed as a primary diet component. While the catalytic activity associated with β-ODAP formation was demonstrated more than 50 years ago, the enzyme responsible for this activity has not been identified. Here, we report on the identity, activity, 3D structure, and phylogenesis of this enzyme—β-ODAP synthase (BOS). We show that BOS belongs to the benzylalcohol O-acetyltransferase, anthocyanin O-hydroxycinnamoyltransferase, anthranilate N-hydroxycinnamoyl/benzoyltransferase, deacetylvindoline 4-O-acetyltransferase superfamily of acyltransferases and is structurally similar to hydroxycinnamoyl transferase. Using molecular docking, we propose a mechanism for its catalytic activity, and using heterologous expression in tobacco leaves (Nicotiana benthamiana), we demonstrate that expression of BOS in the presence of its substrates is sufficient for β-ODAP production in vivo. The identification of BOS may pave the way toward engineering β-ODAP–free grass pea cultivars, which are safe for human and animal consumption.

Algal proteins: Production strategies and nutritional and functional properties

Animal-based proteins are the most consumed worldwide given their well-balanced nutritional composition. However, the growing demand for animal proteins will not be sustainable due to their low conversion efficiency and high environmental footprint. Specific consumers' dietary restrictions and modern trends emphasize the importance of finding alternative sustainable non-animal sources to meet future food (and, in particular, protein) global needs. Algal biomass is considered a relevant alternative, presenting advantages over terrestrial biomass such as higher growth rate, low water consumption, no competition for arable land, carbon-neutral emissions, and production of numerous bioactive compounds. This review provides an overview of recent research advances on algae as source of proteins, including production strategies from relevant protein-producing species. Particular emphasis will be given to algae protein current applications and forthcoming challenges of their use. Nutritional and functional aspects of algae biomass or its protein-enriched fractions will be overviewed.

Direct and Indirect Neurotoxic Potential of Metal/Metalloids in Plants and Fungi Used for Food, Dietary Supplements, and Herbal Medicine

Plants and mushrooms bioconcentrate metals/metalloids from soil and water such that high levels of potentially neurotoxic elements can occur in cultivated and wild species used for food. While the health effects of excessive exposure to metals/metalloids with neurotoxic potential are well established, overt neurological disease from prolonged ingestion of contaminated botanicals has not been recognized. However, the presence of metal elements may affect levels of botanical neurotoxins in certain plants and mushrooms that are established causes of acute and chronic neurological disease.

Lathyrism and Socioeconomic Disparities: A Neglected Public Health Problem in Northeast Ethiopia

Lathyrism is an incurable neurological disorder, resulting from excessive consumption of grass pea (Lathyrus sativus), which clinically manifests as paralysis of lower limbs. Because of the high production of grass peas, a large number of people are expected to be affected by the disease in Northeast Ethiopia. However, there is no comprehensive study that quantified the magnitude of the problem. Therefore, in this study, we determined the prevalence of lathyrism and socioeconomic disparities in Northeast Ethiopia. A community-based cross-sectional study was used which used a quantitative method of data collection from January to February 2019. Data were collected from a total of 2,307 inhabitants in the study area using structured questionnaires. Lathyrism cases were identified using a case definition of symmetrical spastic leg weakness, and subacute or insidious onset, with no sensory deficit, and with a history of grass pea consumption before and at the onset of paralysis. The majority (56.8%) of participants were male, and 34.7% were aged 45 years or older. Overall, the prevalence of lathyrism was 5.5%, and it was higher in males (7.9%) than in females (2.5%). Moreover, the prevalence was higher among farmers (7.0%) than merchants (0.3%), very poor economic status (7.2%) than very rich (1.1%), who produced (9.6%) grass pea than not produced (0.9%), and those who used clay pottery (6.2%) than metal (4.8%) for cooking. The prevalence of lathyrism in Northeast Ethiopia is remarkably high. Therefore, we recommend lathyrism to be among the list of reportable health problems and incorporated in the national routine surveillance system.

Tempeh: A semicentennial review on its health benefits, fermentation, safety, processing, sustainability, and affordability

Tempeh is a fermented food made of mainly soybeans and is a nutritious, affordable, and sustainable functional source of protein. Globally, tempeh is a widely accepted fermented product. Although there is a growing body of literature on tempeh, most research has focused on unfermented soybeans, thus the impact of tempeh fermentation on biological properties of soybeans has been largely left scattered. The objective of this review is to summarize the literature of tempeh fermentation over the past 60 years. A search of articles on tempeh published from 1960 to 2020 was performed using the Cochrane Library, Web of Science, EBSCOhost FSTA database, and Google Scholar. References from identified articles were reviewed for additional sources. In total, 321 papers were selected for this review, of which 64 papers were related to the health benefits of tempeh. This review concluded that sufficient evidence exists in the literature supporting tempeh fermentation as a low-cost, health-promoting, and sustainable food processing technology to produce protein-rich foods using various beans, legumes, and grains. This comprehensive review suggests further studies are needed on tempeh fermentation and its impact on human health; research and standardization of nonsoy tempeh; assessment of food safety-improving modification in tempeh production system; and initiatives supporting the sourcing of local ingredients in tempeh production.

Misincorporation Proteomics Technologies: A Review

Proteinopathies are diseases caused by factors that affect proteoform conformation. As such, a prevalent hypothesis is that the misincorporation of noncanonical amino acids into a proteoform results in detrimental structures. However, this hypothesis is missing proteomic evidence, specifically the detection of a noncanonical amino acid in a peptide sequence. This review aims to outline the current state of technology that can be used to investigate mistranslations and misincorporations whilst framing the pursuit as Misincorporation Proteomics (MiP). The current availability of technologies explored herein is mass spectrometry, sample enrichment/preparation, data analysis techniques, and the hyphenation of approaches. While many of these technologies show potential, our review reveals a need for further development and refinement of approaches is still required.

Identification of Lathyrus sativus plant volatiles causing behavioral preference of Aphis craccivora

BACKGROUND

The viviparous aphid Aphis craccivora Koch (Hemiptera: Aphididae) is a serious threat to the crop yield of Lathyrus sativus L. (Fabaceae), commonly known as grass pea. The synthetic insecticides applied to control this insect pest are not safe for the environment. Hence, it is necessary to find volatile organic compounds (VOCs) from two cultivars [BIO L 212 Ratan (BIO) and Nirmal B-1 (NIR)] of L. sativus plants causing behavioral preference of A. craccivora.

RESULTS

The VOCs from undamaged (UD), insect-damaged (ID) [plants on which 50 or 100 adults of A. craccivora were fed for 4 h (ID 50 or ID 100)], and mechanically damaged (MD) plants were identified and quantified by gas chromatography-mass spectrometry and gas chromatography-flame ionization detection analyses, respectively. Total VOCs were higher in ID plants compared to UD plants of each cultivar. However, total VOCs were higher in NIR cultivar compared to BIO cultivar for both UD and ID plants. Benzyl alcohol was predominant in volatile extracts of all treatments. In Y-tube olfactometer bioassays, females showed preference towards volatile extracts of UD, ID, and MD plants of each cultivar compared to the control solvent (CH₂ Cl₂ ). Insects preferred certain synthetic blends comparable to volatile extracts of UD, ID, and MD plants of each L. sativus cultivar against the control solvent.

CONCLUSION

Females preferred a synthetic blend of benzyl alcohol, 1,3-diethylbenzene, thymol, and 1-hexadecene at ratios of 142.49: 62.03:1.18:1 dissolved in 25 μL of CH₂ Cl₂ in olfactometer bioassays, which could be used in developing lures to control this insect pest.

Compared digestibility of plant protein isolates by using the INFOGEST digestion protocol

The use of ingredients based on plant protein isolates is being promoted due to sustainability and health reasons. However, it is necessary to explore the behaviour of plant protein isolates during gastrointestinal digestion including the profile of released free amino acids and the characterization of resistant domains to gastrointestinal digestion. The aim of the present study was to monitor protein degradation of four legume protein isolates: garden pea, grass pea, soybean and lentil, using the harmonized Infogest in vitro digestion protocol. In vitro digests were characterized regarding protein, peptide and free amino acid content. Soybean was the protein isolate with the highest percentage of insoluble nitrogen at the end of the digestion (12%), being this fraction rich in hydrophobic amino acids. Free amino acids were mainly released during the intestinal digestion, comprising 21-24% of the total nitrogen content, while the percentage of nitrogen corresponding to peptides ranged from 66 to 76%. Legume globulins were resistant to gastric digestion whereas they were hydrolysed into peptides and amino acids during the intestinal phase. However, the molecular weight (MW) distribution demonstrated that all intestinal digests, except those from soybean, contained peptides with MW > 4 kDa at the end of gastrointestinal digestion. The profile of free amino acids released during digestion supports legume protein isolates as an excellent source of essential amino acids to be used in protein-rich food products. Peptides released during digestion matched with previously reported epitopes from the same plant species or others, explaining the ability to induce allergic reactions and cross-linked reactivity.

Effects of phytase-supplemented fermentation and household processing on the nutritional quality of Lathyrus sativus L. seeds

Grass pea (Lathyrus sativus L.) is commonly consumed in cooked, fermented, and roasted forms in Ethiopia. However, the impacts of household processing practices on its nutrients, antinutrients, and toxic compounds have not been adequately studied. Therefore, the effects of household processing and fermentation in the presence and absence of a phytase on the contents of β-N-oxalyl-L-α,β-diaminopropionic acid (β-ODAP), myo-inositol phosphates, crude protein, minerals and the in vitro bioaccessibility were investigated. Fermentation exhibited a significant decline in β-ODAP (13.0-62.0%) and phytate (7.3-90.5%) irrespective of the presence of phytase. Pressure and pan cooking after discarding the soaking water resulted in a 27.0 and 16.2% reduction in β-ODAP. A 30% reduction in phytate was observed during germination followed by roasting. In addition, germination resulted in a significant (p < 0.05) increase in crude protein. Germination and germination followed by roasting resulted in the highest Fe bioaccessibilities (more than 25 fold higher compared to untreated samples) followed by pressure cooking and soaking. Processing also improved Zn bioaccessibilities by 50.0% (soaked seed without soaking water), 22.5% (soaked seed with soaking water), and 4.3% (germination). Thus, the processing technologies applied were capable of reducing the content of phytate (InsP6) and β-ODAP with a concomitant increase in mineral bioaccessibilities. Processing of grass peas could therefore contribute to their more widespread utilization.

Toxin Degradation by Rumen Microorganisms: A Review

Animal feeds may contain exogenous compounds that can induce toxicity when ruminants ingest them. These toxins are secondary metabolites originating from various sources including plants, bacteria, algae and fungi. Animal feed toxins are responsible for various animal poisonings which negatively impact the livestock industry. Poisoning is more frequently reported in newly exposed, naïve ruminants while ‘experienced’ ruminants are observed to better tolerate toxin-contaminated feed. Ruminants can possess detoxification ability through rumen microorganisms with the rumen microbiome able to adapt to utilise toxic secondary metabolites. The ability of rumen microorganisms to metabolise these toxins has been used as a basis for the development of preventative probiotics to confer resistance against the poisoning to naïve ruminants. In this review, detoxification of various toxins, which include plant toxins, cyanobacteria toxins and plant-associated fungal mycotoxins, by rumen microorganisms is discussed. The review will include clinical studies of the animal poisoning caused by these toxins, the toxin mechanism of action, toxin degradation by rumen microorganisms, reported and hypothesised detoxification mechanisms and identified toxin metabolites with their toxicity compared to their parent toxin. This review highlights the commercial potential of rumen inoculum derived probiotics as viable means of improving ruminant health and production.

What is the Difference between the Response of Grass Pea (Lathyrus sativus L.) to Salinity and Drought Stress?—A Physiological Study

Understanding the mechanisms of plant tolerance to osmotic and chemical stress is fundamental to maintaining high crop productivity. Soil drought often occurs in combination with physiological drought, which causes chemical stress due to high concentrations of ions. Hence, it is often assumed that the acclimatization of plants to salinity and drought follows the same mechanisms. Grass pea (Lathyrus sativus L.) is a legume plant with extraordinary tolerance to severe drought and moderate salinity. The aim of the presented study was to compare acclimatization strategies of grass pea seedlings to osmotic (PEG) and chemical (NaCl) stress on a physiological level. Concentrations of NaCl and PEG were adjusted to create an osmotic potential of a medium at the level of 0.0, −0.45 and −0.65 MPa. The seedlings on the media with PEG were much smaller than those growing in the presence of NaCl, but had a significantly higher content percentage of dry weight. Moreover, the stressors triggered different accumulation patterns of phenolic compounds, soluble and insoluble sugars, proline and β-N-oxalyl-L-α,β-diamino propionic acid, as well as peroxidase and catalase activity. Our results showed that drought stress induced a resistance mechanism consisting of growth rate limitation in favor of osmotic adjustment, while salinity stress induced primarily the mechanisms of efficient compartmentation of harmful ions in the roots and shoots. Furthermore, our results indicated that grass pea plants differed in their response to drought and salinity from the very beginning of stress occurrence.

The role of Lathyrus sativus flower surface wax in short-range attraction and stimulant for nymph laying by an adult viviparous aphid

Aphis craccivora Koch (Hemiptera: Aphididae) is an important pest of Lathyrus sativus L. plants, and causes retarded plant growth and loss of seed production. The insect sucks cell sap from flowers and lays nymphs on flowers. Hence, an attempt has been made to observe whether flower surface wax compounds (alkanes and free fatty acids) from two cultivars (BIO L 212 Ratan and Nirmal B-1) of L. sativus could act as short-range attractant and stimulant for nymph laying by adult viviparous females. The n-hexane extracts of flower surface waxes were analyzed by TLC, GC-MS and GC-FID analyses. Twenty one and 22 n-alkanes between n-C12 and n-C36 were detected in BIO L 212 Ratan and Nirmal B-1, respectively; whereas 12 free fatty acids between C12:0 and C22:0 were identified in both cultivars. Pentadecane and tridecanoic acid were predominant n-alkane and free fatty acid, respectively. One flower equivalent surface wax of both cultivars served as short-range attractant and stimulant for nymph laying through Y-tube choice experiments and I-tube viviparity assays, respectively, by adult viviparous females. A synthetic blend of nonacosane, tridecanoic acid and linoleic acid, and a synthetic blend of tetradecane, pentadecane, nonacosane, tridecanoic acid and linoleic acid resembling in amounts as present in one flower equivalent surface wax of BIO L 212 Ratan and Nirmal B-1, respectively, served as short-range attractant and stimulant for nymph laying by adult viviparous females. This study suggests that both these blends could be used in lures in the development of baited traps in pest management programmes.

Proteomic Comparison of Three Extraction Methods Reveals the Abundance of Protease Inhibitors in the Seeds of Grass Pea, a Unique Orphan Legume

Grass pea is an orphan legume that is grown in many places in the world. It is a high-protein, drought-tolerant legume that is capable of surviving extreme environmental challenges and can be a sole food source during famine. However, grass pea produces the neurotoxin β-N-oxalyl-L-α,β-diaminopropionic acid (β-ODAP), which can cause a neurological disease. This crop is promising as a food source for both animals and humans if β-ODAP levels and other antinutritional factors such as protease inhibitors are lowered or removed. To understand more about these proteins, a proteomic analysis of grass pea was conducted using three different extraction methods to determine which was more efficient at isolating antinutritional factors. Seed proteins extracted with Tris-buffered saline (TBS), 30% ethanol, and 50% isopropanol were identified by mass spectrometry, resulting in the documentation of the most abundant proteins for each extraction method. Mass spectrometry spectral data and BLAST2GO analysis led to the identification of 1376 proteins from all extraction methods. The molecular function of the extracted proteins revealed distinctly different protein functional profiles. The majority of the TBS-extracted proteins were annotated with nutrient reservoir activity, while the isopropanol extraction yielded the highest percentage of endopeptidase proteinase inhibitors. Our results demonstrate that the 50% isopropanol extraction method was the most efficient at isolating antinutritional factors including protease inhibitors.

Grass pea (Lathyrus sativus L.): orphan crop, nutraceutical or just plain food?

Although grass pea is an environmentally successful robust legume with major traits of interest for food and nutrition security, the genetic potential of this orphan crop has long been neglected. Grass pea (Lathyrus sativus L.) is a Neolithic plant that has survived millennia of cultivation and has spread over three continents. It is a robust legume crop that is considered one of the most resilient to climate changes and to be survival food during drought-triggered famines. The hardy penetrating root system allows the cultivation of grass pea in various soil types, including marginal ones. As an efficient nitrogen fixer, it meets its own nitrogen requirements and positively benefits subsequent crops. However, already in ancient India and Greece, overconsumption of the seeds and a crippling neurological disorder, later coined neurolathyrism, had been linked. Overemphasis of their suspected toxic properties has led to disregard the plant's exceptionally positive agronomic properties and dietary advantages. In normal socio-economic and environmental situations, in which grass pea is part of a balanced diet, neurolathyrism is virtually non-existent. The etiology of neurolathyrism has been oversimplified and the deficiency in methionine in the diet has been overlooked. In view of the global climate change, this very adaptable and nutritious orphan crop deserves more attention. Grass pea can become a wonder crop if the double stigma on its reputation as a toxic plant and as food of the poor can be disregarded. Additionally, recent research has exposed the potential of grass pea as a health-promoting nutraceutical. Development of varieties with an improved balance in essential amino acids and diet may be relevant to enhance the nutritional value without jeopardizing the multiple stress tolerance of this promising crop.

Orphan crops: their importance and the urgency of improvement

Due to significant contributions of orphan crops in the economy of the developing world, scientific studies need to be promoted on these little researched but vital crops of smallholder farmers and consumers. Food security is the main challenge in the developing world, particularly in the least developed countries. Orphan crops play a vital role in the food security and livelihood of resource-poor farmers and consumers in these countries. Like major crops, there are members of all food types-cereals, legumes, vegetables and root and tuber crops, that are considered to be orphan crops. Despite their huge importance for present and future agriculture, orphan crops have generally received little attention by the global scientific community. Due to this, they produce inferior yields in terms of both quantity and quality. The major bottlenecks affecting the productivity of these crops are little or no selection of improved genetic traits, extreme environmental conditions and unfavorable policy. However, some orphan crops have recently received the attention of the global and national scientific community where advanced research and development initiatives have been launched. These initiatives which implement a variety of genetic and genomic tools targeted major constraints affecting productivity and/or nutritional quality of orphan crops. In this paper, some of these initiatives are briefly described. Here, I provide key suggestions to relevant stakeholders regarding improvement of orphan crops. Concerted efforts are urgently needed to advance the research and development of both the major and orphan crops so that food security will be achieved and ultimately the livelihood of the population will be improved.

Lathyrus sativus Originating from Different Geographical Regions Reveals Striking Differences in Kunitz and Bowman-Birk Inhibitor Activities

Grass pea (Lathyrus sativus L.) is an important legume commonly grown in arid and semi-arid regions. This protein-rich legume performs well even under harsh environmental conditions and is considered to be a strategic famine food in developing countries. Unfortunately, its potential usage is greatly limited as a result of the presence of antinutritional factors, including the neuroexcitatory amino acid β-N-oxalyl-l-α,β-diaminopropionic acid (β-ODAP) and protease inhibitors. β-ODAP is responsible for a neurodegenerative syndrome that results in the paralysis of lower limbs, while protease inhibitors affect protein digestibility, resulting in reduced growth. Concerted research efforts have led to development of grass pea cultivars with reduced β-ODAP content. In contrast, very little information is available on the protease inhibitors of L. sativus. In this study, we have conducted biochemical characterization of 51 L. sativus accessions originating from different geographical regions. Sodium dodecyl sulfate polyacrylamide gel electrophoresis analyses of seed globulins and prolamins revealed striking similarity in their protein profile, although geographic-specific variations in profiles was also evident. Measurement of Bowman-Birk chymotrypsin inhibitor (BBi) and Kunitz trypsin inhibitor (KTi) activities in accessions revealed striking differences among them. Amino acid sequence alignment of grass pea BBi and KTi revealed significant homology to protease inhibitors from several legumes. Real-time polymerase chain reaction analysis demonstrated high-level expression of BBi and KTi in dry seeds and weak expression in other organs. Our study demonstrates substantial variation in BBi and KTi among grass pea accessions that could be exploited in breeding programs for the development of grass pea lines that are devoid of these antinutritional factors.

Manipulation of oxalate metabolism in plants for improving food quality and productivity

Oxalic acid is a naturally occurring metabolite in plants and a common constituent of all plant-derived human diets. Oxalic acid has diverse unrelated roles in plant metabolism, including pH regulation in association with nitrogen metabolism, metal ion homeostasis and calcium storage. In plants, oxalic acid is also a pathogenesis factor and is secreted by various fungi during host infection. Unlike those of plants, fungi and bacteria, the human genome does not contain any oxalate-degrading genes, and therefore, the consumption of large amounts of plant-derived oxalate is considered detrimental to human health. In this review, we discuss recent biotechnological approaches that have been used to reduce the oxalate content of plant tissues.

Identification and Characterization of β-Lathyrin, an Abundant Glycoprotein of Grass Pea ( Lathyrus sativus L.), as a Potential Allergen

Grass pea, a protein-rich, high-yielding, and drought-tolerant legume, is used as food and livestock feed in several tropical and subtropical regions of the world. The abundant seed proteins of grass pea are salt-soluble globulins, which can be separated into vicilins and legumins. In many other legumes, the members of vicilin seed proteins have been identified as major allergens. However, very little information is available on the allergens of grass pea. In this study, we have identified an abundant 47 kDa protein from grass pea, which was recognized by immunoglobulin E (IgE) antibodies from sera drawn from several peanut-allergic patients. The IgE-binding 47 kDa protein was partially purified by affinity chromatography on a Con-A sepharose column. Matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry analysis of the 47 kDa grass pea protein revealed sequence homology to 47 kDa vicilin from pea and Len c 1 from lentil. Interestingly the grass pea vicilin was found to be susceptible to pepsin digestion in vitro. We have also isolated a cDNA encoding the grass pea 47 kDa vicilin (β-lathyrin), and the deduced amino acid sequence revealed extensive homology to several known allergens, including those from peanut and soybean. A homology model structure of the grass pea β-lathyrin, generated using the X-ray crystal structure of the soybean β-conglycinin β subunit as a template, revealed potential IgE-binding epitopes located on the surface of the molecule. The similarity in the three-dimensional structure and the conservation of the antigenic epitopes on the molecular surface of vicilin allergens explains the IgE-binding cross-reactivity.

Biosynthesis and biotechnological application of non-canonical amino acids: Complex and unclear

Compared with the better-studied canonical amino acids, the distribution, metabolism and functions of natural non-canonical amino acids remain relatively obscure. Natural non-canonical amino acids have been mainly discovered in plants as secondary metabolites that perform diversified physiological functions. Due to their specific characteristics, a broader range of natural and artificial non-canonical amino acids have recently been applied in the development of functional materials and pharmaceutical products. With the rapid development of advanced methods in biotechnology, non-canonical amino acids can be incorporated into peptides, proteins and enzymes to improve the function and performance relative to their natural counterparts. Therefore, biotechnological application of non-canonical amino acids in artificial bio-macromolecules follows the central goal of synthetic biology to: create novel life forms and functions. However, many of the non-canonical amino acids are synthesized via chemo- or semi-synthetic methods, and few non-canonical amino acids can be synthesized using natural in vivo pathways. Therefore, further research is needed to clarify the metabolic pathways and key enzymes of the non-canonical amino acids. This will lead to the discovery of more candidate non-canonical amino acids, especially for those that are derived from microorganisms and are naturally bio-compatible with chassis strains for in vivo biosynthesis. In this review, we summarize representative natural and artificial non-canonical amino acids, their known information regarding associated metabolic pathways, their characteristics and their practical applications. Moreover, this review summarizes current barriers in developing in vivo pathways for the synthesis of non-canonical amino acids, as well as other considerations, future trends and potential applications of non-canonical amino acids in advanced biotechnology.

Current scenario of consumption of Lathyrus sativus and lathyrism in three districts of Chhattisgarh State, India

Lathyrism is a disease caused by excessive consumption of grass pea, Lathyrus sativus especially under conditions of severe drought. Grass pea contains 3-N-oxalyl-L-2, 3-diaminopropanoic acid (β-ODAP) a putative neurotoxin which acts through excitatory mechanism causing Neurolathyrism. Due to awareness of the disease, availability of food and levels of consumption of L. sativus there is reduction in lathyrism cases where higher consumption of L. sativus is reported in India. The present study was undertaken with the objective to assess the current scenario of consumption of L. sativus, incidence of cases of lathyrism, β-ODAP, protein and amino acids content in L. sativus pulse collected from three districts (Bilaspur, Durg and Raipur) of Chattisgarh state. For this purpose, a total of 17,755 (13,129 rural and 4626 urban) individuals from 151 villages and 60 wards from urban area were covered for clinical examination. Out of total 5769 households (HHs) covered during the survey, 1602 HHs were cultivators, 1791 HHs non-cultivators and 2376 agricultural and other labourers. A one day 24-hour re-call diet survey was carried out in 5758 HHs (4549 rural and 1209 urban). A total of 360 split grass pea (SGP) samples were collected to estimate β-ODAP, protein and amino acids content. Results of the study revealed that an average consumption of SGP was 20.9 gm/CU/day in Bilaspur and no consumption was reported among urban population of Raipur. Only nine old cases of lathyrism were found during the study. The mean β-ODAP content in SGP was 0.63 ± 0.14, 0.65 ± 0.13 and 0.65 ± 0.14 gm/100 gm, whereas the protein content was 27.0 ± 2.39, 27.0 ± 1.99 and 26.7 ± 1.90 gm/100 gm in samples collected from Bilaspur, Durg and Raipur districts respectively. Arginine content was high in SGP and sulphur containing amino acids (cysteine and methionine) were less than other amino acids. In conclusion, the consumption of SGP was lower in these three districts with lower β-ODAP content than earlier reports, thus the lower prevalence of lathyrism in the districts surveyed.

Tissue specific expression and in-silico characterization of a putative cysteine synthase gene from Lathyrus sativus L

Grass pea (Lathyrus sativus L.) is a worldwide popular pulse crop especially for its protein rich seeds with least production cost. However, the use of the crop became controversial due to the presence of non-protein amino acid, β-N-oxalyl-L-α, β-diaminopropionic acid (β-ODAP) in its seed and leaf, which is known as the principle neurotoxin to cause neurolathyrism (a motor neurodegenerative disease of humans and animals) during prolonged consumption as regular diet. Till date, the knowledge on β-ODAP biosynthesis in Lathyrus sp. is limited only to a small part of the complex bio-chemical steps involved including a few known sulfur-containing enzymes (viz. cysteine synthase, ODAP synthase etc.). In Lathyrus sativus, biosynthesis of β-ODAP varies differentially in a tissue-specific manner as well as in response to several environmental stresses viz. zinc deficiency, iron over-exposure, moisture stress etc. In the present study, a novel cysteine synthase gene (LsCSase) from Lathyrus sativus L was identified and characterized through bioinformatics approaches. The bioinformatic analysis revealed that LsCSase showed maximum similarity with the O-acetyl serine (thiol) lyase of Medicago truncatula with respect to several significant sequence-specific conserved motifs (cysK, CBS like, ADH_zinc_N, PALP), sub-cellular localization (chloroplast or cytoplasm) etc., similar to other members of cysteine synthase protein family. Moreover, the tissue-specific regulation of the LsCSase as well as its transcriptional activation under certain previously reported stressed conditions (low Zn⁺²-high Fe⁺², PEG induced osmotic stress) were also documented through quantitative real-time PCR analyses, suggesting a possible link between the LsCSase gene activation and β-ODAP biosynthesis to manage external stresses in grass pea. This preliminary study offers a probable way towards the development of less toxic consumer-safe grass pea by down-regulation or deactivation of such gene/s (cysteine synthase) through genetic manipulations.

Metabolomics Approach To Understand Mechanisms of β-N-Oxalyl-l-α,β-diaminopropionic Acid (β-ODAP) Biosynthesis in Grass Pea (Lathyrus sativus L.)

A study was performed to identify metabolic processes associated with β-ODAP synthesis in grass pea using a metabolomics approach. GC-MS metabolomics was performed on seedlings at 2, 6, and 25 days after sowing. A total of 141 metabolites were detected among the three time points representing much of grass pea primary metabolism, including amino acids, carbohydrates, purines, and others. Principal component analysis revealed unique metabolite profiles of grass pea tissues among the three time points. Fold change, hierarchical clustering, and orthogonal projections to latent structures-discriminant analyses, and biochemical pathway ontologies were used to characterize covariance of metabolites with β-ODAP content. The data indicates that alanine and nitrogen metabolism, cysteine and sulfur metabolism, and purine, pyrimidine, and pyridine metabolism were associated with β-ODAP metabolism. Our results reveal the metabolite profiles in grass pea development and provide insights into mechanisms of β-ODAP accumulation and degradation.

An RNA Sequencing Transcriptome Analysis of Grasspea (Lathyrus sativus L.) and Development of SSR and KASP Markers

Grasspea (Lathyrus sativus L., 2n = 14) has great agronomic potential because of its ability to survive under extreme conditions, such as drought and flood. However, this legume is less investigated because of its sparse genomic resources and very slow breeding process. In this study, 570 million quality-filtered and trimmed cDNA sequence reads with total length of over 82 billion bp were obtained using the Illumina NextSeq^TM 500 platform. Approximately two million contigs and 142,053 transcripts were assembled from our RNA-Seq data, which resulted in 27,431 unigenes with an average length of 1,250 bp and maximum length of 48,515 bp. The unigenes were of high-quality. For example, the stay-green (SGR) gene of grasspea was aligned with the SGR gene of pea with high similarity. Among these unigenes, 3,204 EST-SSR primers were designed, 284 of which were randomly chosen for validation. Of these validated unigenes, 87 (30.6%) EST-SSR primers produced polymorphic amplicons among 43 grasspea accessions selected from different geographical locations. Meanwhile, 146,406 SNPs were screened and 50 SNP loci were randomly chosen for the kompetitive allele-specific PCR (KASP) validation. Over 80% (42) SNP loci were successfully transformed to KASP markers. Comparison of the dendrograms according to the SSR and KASP markers showed that the different marker systems are partially consistent with the dendrogram constructed in our study.

β-N-Oxalyl-l-α,β-diaminopropionic Acid (β-ODAP) Content in Lathyrus sativus: The Integration of Nitrogen and Sulfur Metabolism through β-Cyanoalanine Synthase

Grass pea (Lathyrus sativus L.) is an important legume crop grown mainly in South Asia and Sub-Saharan Africa. This underutilized legume can withstand harsh environmental conditions including drought and flooding. During drought-induced famines, this protein-rich legume serves as a food source for poor farmers when other crops fail under harsh environmental conditions; however, its use is limited because of the presence of an endogenous neurotoxic nonprotein amino acid β-N-oxalyl-l-α,β-diaminopropionic acid (β-ODAP). Long-term consumption of Lathyrus and β-ODAP is linked to lathyrism, which is a degenerative motor neuron syndrome. Pharmacological studies indicate that nutritional deficiencies in methionine and cysteine may aggravate the neurotoxicity of β-ODAP. The biosynthetic pathway leading to the production of β-ODAP is poorly understood, but is linked to sulfur metabolism. To date, only a limited number of studies have been conducted in grass pea on the sulfur assimilatory enzymes and how these enzymes regulate the biosynthesis of β-ODAP. Here, we review the current knowledge on the role of sulfur metabolism in grass pea and its contribution to β-ODAP biosynthesis. Unraveling the fundamental steps and regulation of β-ODAP biosynthesis in grass pea will be vital for the development of improved varieties of this underutilized legume.

Improving nutritional quality and fungal tolerance in soya bean and grass pea by expressing an oxalate decarboxylase

Soya bean (Glycine max) and grass pea (Lathyrus sativus) seeds are important sources of dietary proteins; however, they also contain antinutritional metabolite oxalic acid (OA). Excess dietary intake of OA leads to nephrolithiasis due to the formation of calcium oxalate crystals in kidneys. Besides, OA is also a known precursor of β-N-oxalyl-L-α,β-diaminopropionic acid (β-ODAP), a neurotoxin found in grass pea. Here, we report the reduction in OA level in soya bean (up to 73%) and grass pea (up to 75%) seeds by constitutive and/or seed-specific expression of an oxalate-degrading enzyme, oxalate decarboxylase (FvOXDC) of Flammulina velutipes. In addition, β-ODAP level of grass pea seeds was also reduced up to 73%. Reduced OA content was interrelated with the associated increase in seeds micronutrients such as calcium, iron and zinc. Moreover, constitutive expression of FvOXDC led to improved tolerance to the fungal pathogen Sclerotinia sclerotiorum that requires OA during host colonization. Importantly, FvOXDC-expressing soya bean and grass pea plants were similar to the wild type with respect to the morphology and photosynthetic rates, and seed protein pool remained unaltered as revealed by the comparative proteomic analysis. Taken together, these results demonstrated improved seed quality and tolerance to the fungal pathogen in two important legume crops, by the expression of an oxalate-degrading enzyme.

Simple Detection Methods for Antinutritive Factor β-ODAP Present in Lathyrus sativus L. by High Pressure Liquid Chromatography and Thin Layer Chromatography

Lathyrus sativus L. (Grass pea) is the source for cheap and nutritious food choice in drought and famine susceptible zones in greater part of North India and Africa. The non-protein amino acid β-N-oxalyl-L-α,β-diaminopropionic acid (β-ODAP) has been known for decades for its potent neurotoxic effect, causing irreversible neurodegenerative disease "neurolathyrism", present in both seed and leaf of Lathyrus sativus L. and other species in varying proportions. It is crucial to establish a rapid as well as reliable detection methodology for β-ODAP content in various Lathyrus plants. Currently available HPLC based methods involve multi-step derivatization of the sample. To overcome this, we have developed β-ODAP analysis method by HPLC without any prior derivatization. This method is statistically significant in the range of 2 to 100μg/ml and exhibited linear response with r2 > 0.99. Limit of detection and quantitation of the later method was determined to be 5.56 μg/ml and 16.86 μg/ml, respectively. In addition to this, a TLC based method has also been developed. The limit of detection of β-ODAP is 0.6μg and for its substrate, L-1,2-diaminopropionic acid is 5μg. Both HPLC and TLC methods were validated by conducting in-vitro bioconversion test to detect the presence of biocatalyst in plant extract. This method is economical, rapid and simple.

Genotypic Variation in the Concentration of β-N-Oxalyl-L-α,β-diaminopropionic Acid (β-ODAP) in Grass Pea (Lathyrus sativus L.) Seeds Is Associated with an Accumulation of Leaf and Pod β-ODAP during Vegetative and Reproductive Stages at Three Levels of Water Stress

Grass pea (Lathyrus sativus L.) cultivation is limited because of the presence in seeds and tissues of the nonprotein amino acid β-N-oxalyl-L-α,β-diaminopropionic acid (β-ODAP), a neurotoxin that can cause lathyrism in humans. Seven grass pea genotypes differing in seed β-ODAP concentration were grown in pots at three levels of water availability to follow changes in the concentration and amount of β-ODAP in leaves and pods and seeds. The concentration and amount of β-ODAP decreased in leaves in early reproductive development and in pods as they matured, while water stress increased β-ODAP concentration in leaves and pods at these stages. The net amount of β-ODAP in leaves and pods at early podding was positively associated with seed β-ODAP concentration at maturity. We conclude that variation among genotypes in seed β-ODAP concentration results from variation in net accumulation of β-ODAP in leaves and pods during vegetative and early reproductive development.

Determination of β-N-oxalyl-L-α,β-diaminopropionic acid and homoarginine in Lathyrus sativus and Lathyrus cicera by capillary zone electrophoresis

BACKGROUND

Lathyrus species as legumes represent an alternative protein source for human and animal nutrition. Heavy consumption of these species can lead to lathyrism, caused by the non-protein amino acid β-N-oxalyl-l-α,β-diaminopropionic acid (β-ODAP). Currently, there is no well-defined level below which β-ODAP is considered non-toxic. In this work, the β-ODAP content was determined in L. sativus and L. cicera samples to assess their potential toxicity. Homoarginine is another non-protein amino acid found in Lathyrus spp. with interesting implications for human and animal nutrition.

RESULTS

The level of β-ODAP found in these two species ranged from 0.79 to 5.05 mg g(-1). The homoarginine content of the samples ranged from 7.49 to 12.44 mg g(-1).

CONCLUSION

This paper describes an accurate, fast and sensitive method of simultaneous detection and quantification of β-ODAP and homoarginine by capillary zone electrophoresis in L. cicera and L. sativus seeds. Moreover, several methods of extraction were compared to determine the highest performance.

The action of peroxyl radicals, powerful deleterious reagents, explains why neither cholesterol nor saturated fatty acids cause atherogenesis and age-related diseases

Cells respond to alterations in their membrane structure by activating hydrolytic enzymes. Thus, polyunsaturated fatty acids (PUFAs) are liberated. Free PUFAs react with molecular oxygen to give lipid hydroperoxide molecules (LOOHs). In case of severe cell injury, this physiological reaction switches to the generation of lipid peroxide radicals (LOO(·)). These radicals can attack nearly all biomolecules such as lipids, carbohydrates, proteins, nucleic acids and enzymes, impairing their biological functions. Identical cell responses are triggered by manipulation of food, for example, heating/grilling and particularly homogenization, representing cell injury. Cholesterol as well as diets rich in saturated fat have been postulated to accelerate the risk of atherosclerosis while food rich in unsaturated fatty acids has been claimed to lower this risk. However, the fact is that LOO(·) radicals generated from PUFAs can oxidize cholesterol to toxic cholesterol oxides, simulating a reduction in cholesterol level. In this review it is shown how active LOO(·) radicals interact with biomolecules at a speed transcending usual molecule-molecule reactions by several orders of magnitude. Here, it is explained how functional groups are fundamentally transformed by an attack of LOO(·) with an obliteration of essential biomolecules leading to pathological conditions. A serious reconsideration of the health and diet guidelines is required.