Transcriptome profiling illustrates expression signatures of dehydration tolerance in developing grasspea seedlings.

MAIN CONCLUSION: This study highlights dehydration-mediated temporal changes in physicochemical, transcriptome and metabolome profiles indicating altered gene expression and metabolic shifts, underlying endurance and adaptation to stress tolerance in the marginalized crop, grasspea. Grasspea, often regarded as an orphan legume, is recognized to be fairly tolerant to water-deficit stress. In the present study, 3-week-old grasspea seedlings were subjected to dehydration by withholding water over a period of 144 h. While there were no detectable phenotypic changes in the seedlings till 48 h, the symptoms appeared during 72 h and aggravated upon prolonged dehydration. The physiological responses to water-deficit stress during 72-96 h displayed a decrease in pigments, disruption in membrane integrity and osmotic imbalance. We evaluated the temporal effects of dehydration at the transcriptome and metabolome levels. In total, 5201 genes of various functional classes including transcription factors, cytoplasmic enzymes and structural cell wall proteins, among others, were found to be dehydration-responsive. Further, metabolome profiling revealed 59 dehydration-responsive metabolites including sugar alcohols and amino acids. Despite the lack of genome information of grasspea, the time course of physicochemical and molecular responses suggest a synchronized dehydration response. The cross-species comparison of the transcriptomes and metabolomes with other legumes provides evidence for marked molecular diversity. We propose a hypothetical model that highlights novel biomarkers and explain their relevance in dehydration-response, which would facilitate targeted breeding and aid in commencing crop improvement efforts.

Plants with neurotoxic potential in undernourished subjects.

The consumption by humans of plants with potential to induce neurological disorders is widespread, but overt disease surfaces only when the subject's toxic threshold is exceeded. Excessive intake arising from food dependency in the setting of hunger, chronic undernutrition, vitamin deficiency, inadequate detoxication, or other individual susceptibility, can trigger acute encephalopathy (lychee, ackee fruits), sub-acute spastic paraparesis (grasspea, cassava root/leaves) or ataxic neuropathy (cassava root flour). While these disorders are very rarely encountered in high-income countries, they are not only common among impoverished populations but also often occur as outbreaks that impact a significant proportion of an affected community. Unfamiliarity with the adverse effects of plant toxins has sometimes led to the mistaken attribution of nutritional neurotoxic disease to a neurotropic viral or synthetic pesticidal etiology. The combination of human population growth, food and water insecurity, poverty and, with climate change, increased dependency on environmentally tolerant plants with neurotoxic potential, predictably may result in an increased prevalence of nutritional neurotoxic disorders, especially in certain parts of Africa and Asia.

Reducing anti-nutritional factor and enhancing yield with advancing time of planting and zinc application in grasspea in Ethiopia.

BACKGROUND: Grasspea (Lathyrus sativus L.) is an important pulse crop for food, feed and sustainable crop production systems in Ethiopia. Despite its advantages in nutrition and adaptability to harsh climate and low fertile soil, it contains a neurotoxin, ß-N-oxalyl-α,ß-diamiono propionic acid (ß-ODAP), which paralyses the lower limbs and is affected by genotypic and agronomic factors. To determine the effect of zinc application and planting date on yield and ß-ODAP content of two genotypes, experiments were conducted in two regions of Ethiopia. RESULTS: The main effects of variety, sowing date and zinc and their interactions were significant (P < 0.001) for ß-ODAP and seed yield, which had a linear relationship with zinc. For the improved grasspea variety, an application of 20 kg ha-1 zinc showed a reduction of ß-ODAP from 0.15% to 0.088% at Debre Zeit and 0.14% to 0.08% at Sheno and increased its yield from 841 kg ha-1 to 2260 kg ha-1 at Debre Zeit and from 715 to 1835 kg ha-1 at Sheno. Early sowing showed a reduction in ODAP content in relation to the late sowing. CONCLUSION: An application of Zn beyond even 20 kg ha-1 with an early sowing is recommended for the improved variety. © 2017 Society of Chemical Industry.

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.

Integrated nutrient management on oat + grasspea intercropping system: an evaluation of system productivity, economics, energetics and carbon footprint.

A field investigation took place at Central Research Farm of Bidhan Chandra Krishi Viswavidyalaya, West Bengal, India during winter seasons of 2020-21 and 2021-22 with the aim to evaluate system productivity, economics, energetics and carbon footprint (CF) of oat + grasspea intercropping systems under different integrated nutrient managements (INM). The experiment was executed in split-plot design with 4 cropping systems in main plots and 4 levels of nutrient management in sub plots. The 3:3 intercropping system of oat + grasspea ensured highest system productivity, whereas sole grasspea stood best in terms of economics, energetics and environment safety by lowering CF. Notably, INM involving 75% N through urea + 25% N through vermicompost registered significantly higher system productivity in case of 3:3 oat + grasspea intercropping system (CS4N3) (18.77 q ha-1). Further, this intercropping system yielded high economic profitability (net return: US$ 430.4 ha-1, benefit-cost ratio: 1.71) as well as energy indices (energy output: 71179.1 MJ ha-1, net energy gain: 60352.0 MJ ha-1, energy ratio: 6.57 and energy profitability: 5.57). CF was also found relatively low under CS4N3 (Yield scaled CF: 62.2 kg CO2-e q-1). Furthermore, high carbon efficiency (7.92) and carbon sustainability index (6.92) were also exhibited by CS4N3 as it produced maximum carbon output (1801.2 kg ha-1). In conclusion, the 3:3 oat + grasspea intercropping system using INM can be viable option to ensure economic and energy viability and minimize greenhouse gas emissions without compromising system productivity. Particularly, this intercropping system combined with 75% N through urea + 25% N through vermicompost as INM option can be recommended for the cereal and legume growers of India, specifically under intensive cropping scenario.

Impact of Heat and Drought Stress on Grasspea and Its Wild Relatives.

Grasspea (Lathyrus sativus L.) is recognized as a highly drought-tolerant legume. However, excessive consumption of its seeds and green tissues causes neurolathyrism, a condition characterized by an irreversible paralysis of the legs induced by a neurotoxin amino acid called ß-N-oxalyl-L-α, ß- diaminopropionic acid (ß-ODAP). The present study investigated the effects of heat, and combined heat + drought during the reproductive phase on physiological and phenological parameters, yield-related factors, ODAP content, and seed protein of 24 genotypes representing 11 Lathyrus species under controlled conditions. Analysis of variance revealed a highly significant effect (p < 0.001) of stress treatments and genotypes for all the traits. In general, heat stress individually or in combination with drought expedited phenology, reduced relative leaf water content, stimulated proline synthesis, and influenced chlorophyll concentration; the effects were more severe under the combined heat + drought stress. ODAP content in seeds ranged from 0.06 to 0.30% under no-stress conditions. However, under heat stress, there was a significant increase of 33% in ODAP content, and under combined stress (heat + drought), the increase reached 83%. Crude protein content ranged from 15.64 to 28.67% among no stress plants and decreased significantly by 23% under heat stress and by 36% under combined stress. The findings of this study also indicated substantial reductions in growth and grain yield traits under both heat stress and combined heat + drought stress. Six accessions namely IG 66026, IG 65018, IG 65687, IG 118511, IG 64931, and IG65273 were identified as having the most favorable combination of yield, protein content, and seed ODAP levels across all conditions. ODAP content in these six accessions varied from 0.07 to 0.11% under no stress and remained at moderate levels during both heat stress (0.09-0.14%) and combined stress (0.11-0.17%). IG 66026 was identified as the most stable genotype under drought and heat stress conditions with high protein content, and low ODAP content. By identifying those promising accessions, our results have established a basis for forthcoming grasspea breeding initiatives while paving the way for future research exploration into the fundamental mechanisms driving ODAP variation in the presence of both heat and drought stress conditions.

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.

Rediscovering the Potential of Multifaceted Orphan Legume Grasspea- a Sustainable Resource With High Nutritional Values.

The genus Lathyrus consists of more than 184 herbaceous annual and perennial species suitable for multifaceted sustainable food and feed production system in the arid and semi-arid regions of the world. The grasspea is a promising source of protein nutrition. However, its potential is not being utilized fully due to the presence of neurotoxin content (ß-N-oxalyl-l-α, ß diaminopropionic acid, ß-ODAP), a causal agent of non-reversible lower limbs paralysis. The high protein contents in seeds and leaves with ~90% digestibility make it sustainable super food to beat protein malnutrition in future. Therefore, it is desired to breed new grasspea cultivars with low ß-ODAP contents. Limited research has been carried out to date about this feature. A draft genome sequence of grasspea has been recently published that is expected to play a vital role in breeding and identifying the genes responsible for biosynthesis pathway of ß-ODAP contents in grasspea. Efforts to increase awareness about the importance of genus Lathyrus and detoxify ß-ODAP in grasspea are desired and are in progress. Presently, in South Asia, systematic and dedicated efforts to support the farmers in the grasspea growing regions by disseminating low ß-ODAP varieties has resulted in a considerable improvement in reducing the incidence of neurolathyrism. It is expected that the situation will improve further by mainstreaming grasspea cultivation by implementing different approaches such as the development and use of low ß-ODAP varieties, strengthening government policies and improved detox methods. The present review provides insight into the multifaceted characteristics of sustainable nutritious grasspea in the global and Indian perspective.

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.

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 NextSeqTM 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.

Resistance of Lathyrus Species and Accessions to the Northern Root-knot Nematode, Meloidogyne hapla.

The leguminous plant genus Lathyrus contains many species useful for soil conservation and reclamation. Some of these species may also have vaIue in the United States for forage production. The extent of genetic variation among Lathyrus populations in reaction to most disease pathogens is not known. We examined 28 USDA Agricultural Research Service Plant Introduction accessions representing 16 Lathyrus species for their ability to tolerate attack by the northern root-knot nematode, Meloidogyne hapla. There were differences in the percentage of root tissue galled and in the nematode reproductive index among species and among accessions within species. Root biomass of infected plants was significantly less than that of uninfected plants of the same accession. Accessions of L. ochrus and L. tingitanus were susceptible to M. hapla, whereas L. latifolius, L. sylvestris, and L. hirsutus were resistant. The variation among Lathyrus spp. in root galling and reproductive indices ofM. hapla warrant the inclusion of these traits in Lathyrus breeding programs.