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Bitter vetch (Vicia ervilia Willd.) is a traditional Mediterranean-West Asian legume, mainly used as livestock feed because of its toxic non-proteinogenic amino acid, canavanine. However, historical sources suggest its past human consumption. Currently, bitter vetch is a minor crop confined to marginal soils in semi-arid regions, presenting a potential alternative protein source amid projected climate changes. This study evaluated the nutritional and sensory attributes of bitter vetch seeds processed through various household methods. Germination and cooking significantly reduced the canavanine content by 28% and 60%, respectively. Incorporating bitter vetch flour (BVF) into wheat bread enhanced protein and fiber contents without substantially altering carbohydrate and lipid levels, and the baking process reduced the canavanine content by 40%. Bitter vetch flour enriched the bread with iron and calcium, contributing significantly to their daily nutritional intakes. Sensory evaluations indicated positive reception for bread with 12% BVF, achieving a balance between nutritional enhancement and consumer acceptance. This study identifies bitter vetch seeds as a valuable resource for improving bread formulations with corrected gluten contents and enhanced protein quality, as measured using protein-digestibility-corrected amino acid score (PDCAAS) values. With strategic processing and formulation adjustments, bitter vetch has the potential to re-emerge as a feasible high-protein grain crop, promoting sustainable farming.

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Symbiotic nitrogen fixation is a major contributor of N in agricultural ecosystems, but the establishment of legume-rhizobium symbiosis is highly affected by soil salinity. Our interest is focused on the use of non-rhizobial endophytes to assist the symbiosis between chickpea and its microsymbiont under salinity to avoid loss of production and fertility. Our aims were (1) to investigate the impact of salinity on both symbiotic partners; including on early events of the Mesorhizobium-chickpea symbiosis, and (2) to evaluate the potential of four non-rhizobial endophytes isolated from legumes native to arid regions (Phyllobacterium salinisoli, P. ifriqiyense, Xanthomonas translucens, and Cupriavidus respiraculi) to promote chickpea growth and nodulation under salinity. Our results show a significant reduction in chickpea seed germination rate and in the microsymbiont Mesorhizobium ciceri LMS-1 growth under different levels of salinity. The composition of phenolic compounds in chickpea root exudates significantly changed when the plants were subjected to salinity, which in turn affected the nod genes expression in LMS-1. Furthermore, the LMS-1 response to root exudate stimuli was suppressed by the presence of salinity (250 mM NaCl). On the contrary, a significant upregulation of exoY and otsA genes, which are involved in exopolysaccharide and trehalose biosynthesis, respectively, was registered in salt-stressed LMS-1 cells. In addition, chickpea co-inoculation with LMS-1 along with the consortium containing two non-rhizobial bacterial endophytes, P. salinisoli and X. translucens, resulted in significant improvement of the chickpea growth and the symbiotic performance of LMS-1 under salinity. These results indicate that this non-rhizobial endophytic consortium may be an appropriate ecological and safe tool to improve chickpea growth and its adaptation to salt-degraded soils.

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Information about the amino acid (AA) supply of locally produced protein supplements to dairy cow metabolism is needed to design sustainable diets for milk production. In this dairy cow experiment, grass silage and cereal-based diets supplemented with isonitrogenous amounts of rapeseed meal (RSM), faba beans (FB) and blue lupin seeds (BL) were compared with a control diet (CON) without protein supplementation. The diets were arranged as a 4 × 4 Latin Square using periods of 21 days, and four rumen-cannulated Nordic Red dairy cows were used in the experiment. The intake of all AAs increased in response to protein supplementation and was for many individual AAs higher when RSM rather than the grain legumes FB and BL were fed. The total AA flow at the omasal canal was 3 026, 3 371, 3 373 and 3 045 g/day for cows fed CON, RSM, FB and BL, respectively, but only RSM resulted in higher milk protein output. This may be explained by the higher provision of essential AA for milk protein synthesis when RSM was fed. The cows fed FB showed some positive features such as a tendency for greater omasal flow of branched-chain AA compared with BL. Overall, low plasma methionine and/or glucose concentrations in all treatments suggest that their supply was possibly limiting further production responses under the dietary conditions of the current study. It seems that the benefits of grain legume supplementation are limited when high-quality grass silage and cereal-based diets are used as the basal diet, but higher responses in amino acid supply and subsequent production responses can be expected when RSM is used.

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Grain legumes play a crucial role in human nutrition and as a staple crop for low-income farmers in developing and underdeveloped nations, contributing to overall food security and agroecosystem services. Viral diseases are major biotic stresses that severely challenge global grain legume production. In this review, we discuss how exploring naturally resistant grain legume genotypes within germplasm, landraces, and crop wild relatives could be used as promising, economically viable, and eco-environmentally friendly solution to reduce yield losses. Studies based on Mendelian and classical genetics have enhanced our understanding of key genetic determinants that govern resistance to various viral diseases in grain legumes. Recent advances in molecular marker technology and genomic resources have enabled us to identify genomic regions controlling viral disease resistance in various grain legumes using techniques such as QTL mapping, genome-wide association studies, whole-genome resequencing, pangenome and 'omics' approaches. These comprehensive genomic resources have expedited the adoption of genomics-assisted breeding for developing virus-resistant grain legumes. Concurrently, progress in functional genomics, especially transcriptomics, has helped unravel underlying candidate gene(s) and their roles in viral disease resistance in legumes. This review also examines the progress in genetic engineering-based strategies, including RNA interference, and the potential of synthetic biology techniques, such as synthetic promoters and synthetic transcription factors, for creating viral-resistant grain legumes. It also elaborates on the prospects and limitations of cutting-edge breeding technologies and emerging biotechnological tools (e.g., genomic selection, rapid generation advances, and CRISPR/Cas9-based genome editing tool) in developing virus-disease-resistant grain legumes to ensure global food security.

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Ascochyta lentis, the causal organism of Ascochyta blight (AB) of lentil (Lens culinaris), has been shown to produce an avirulence effector protein that mediates AB resistance in certain lentil cultivars. The two known forms of the effector protein were identified from a biparental mapping population between isolates that have reciprocal virulence on 'PBA Hurricane XT' and 'Nipper'. The effector AlAvr1-1 was described for the PBA Hurricane XT-avirulent isolate P94-24 and AlAvr1-2 characterized in the PBA Hurricane XT-virulent isolate AlKewell. Here, we performed a genome-wide association study to identify other loci associated with AB for a differential set of lentil cultivars from a diverse panel of isolates collected in the Australian lentil-growing regions from 2013 to 2020. The chromosome 3 AlAvr1 locus was strongly associated with the PBA Hurricane XT, 'Indianhead', and Nipper disease responses, but one other genomic region on chromosome 11 was also associated with the Nipper disease trait. Our results corroborate earlier work that identified the AlAvr1 locus for field-collected isolates that span the period before release and after widespread adoption of PBA Hurricane XT. A multiplex PCR assay was developed to differentiate the genes AlAvr1-1 and AlAvr1-2 to predict PBA Hurricane XT avirulence and pathotype designation in the diversity panel. Increasing numbers of the PBA Hurricane XT-virulent pathotype 2 isolates across that time indicate strong selection for isolates with the AlAvr1-2 allele. Furthermore, one other region of the A. lentis genome may contribute to the pathogen-host interaction for lentil AB.

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Grain legumes are a rich source of dietary protein for millions of people globally and thus a key driver for securing global food security. Legume plant-based 'dietary protein' biofortification is an economic strategy for alleviating the menace of rising malnutrition-related problems and hidden hunger. Malnutrition from protein deficiency is predominant in human populations with an insufficient daily intake of animal protein/dietary protein due to economic limitations, especially in developing countries. Therefore, enhancing grain legume protein content will help eradicate protein-related malnutrition problems in low-income and underprivileged countries. Here, we review the exploitable genetic variability for grain protein content in various major grain legumes for improving the protein content of high-yielding, low-protein genotypes. We highlight classical genetics-based inheritance of protein content in various legumes and discuss advances in molecular marker technology that have enabled us to underpin various quantitative trait loci controlling seed protein content (SPC) in biparental-based mapping populations and genome-wide association studies. We also review the progress of functional genomics in deciphering the underlying candidate gene(s) controlling SPC in various grain legumes and the role of proteomics and metabolomics in shedding light on the accumulation of various novel proteins and metabolites in high-protein legume genotypes. Lastly, we detail the scope of genomic selection, high-throughput phenotyping, emerging genome editing tools, and speed breeding protocols for enhancing SPC in grain legumes to achieve legume-based dietary protein security and thus reduce the global hunger risk.

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Grain legumes were domesticated in parallel with cereals in several regions of the world and formed the economic basis of early farming cultures. Since then, legumes have played a vital role in human and animal diets and in fostering agrobiodiversity. Increasing grain legume cultivation will be crucial to safeguard nutritional security and the resilience of agricultural ecosystems across the globe. A better understanding of the molecular underpinnings of domestication and crop evolution of grain legumes may be translated into practical approaches in modern breeding programs to stabilize yield, which is threatened by evolving pathogens and changing climates. During recent decades, domestication research in all crops has greatly benefited from the fast progress in genomic technologies. Yet still, many questions surrounding the domestication and diversification of legumes remain unanswered. In this review, we assess the potential of genomic approaches in grain legume research. We describe the centers of origin and the crucial domestication traits of grain legumes. In addition, we survey the effect of domestication on both above-ground and below-ground traits that have economic importance. Finally, we discuss open questions in grain legume domestication and diversification and outline how to bridge the gap between the preservation of historic crop diversity and their utilization in modern plant breeding.

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The development and promotion of biofortified foods plants are a sustainable strategy for supplying essential micronutrients for human health and nutrition. We set out to identify quantitative trait loci (QTL) associated with carotenoid content in cowpea sprouts. The contents of carotenoids, including lutein, zeaxanthin, and ß-carotene in sprouts of 125 accessions were quantified via high-performance liquid chromatography. Significant variation existed in the profiles of the different carotenoids. Lutein was the most abundant (58 ± 12.8 mg/100 g), followed by zeaxanthin (14.7 ± 3.1 mg/100 g) and ß-carotene (13.2 ± 2.9 mg/100 g). A strong positive correlation was observed among the carotenoid compounds (r ≥ 0.87), indicating they can be improved concurrently. The accessions were distributed into three groups, following their carotenoid profiles, with accession C044 having the highest sprout carotenoid content in a single cluster. A total of 3120 genome-wide SNPs were tested for association analysis, which revealed that carotenoid biosynthesis in cowpea sprouts is a polygenic trait controlled by genes with additive and dominance effects. Seven loci were significantly associated with the variation in carotenoid content. The evidence of variation in carotenoid content and genomic regions controlling the trait creates an avenue for breeding cowpea varieties with enhanced sprouts carotenoid content.

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Raffinose family oligosaccharides (RFOs) are widespread across the plant kingdom, and their concentrations are related to the environment, genotype, and harvest time. RFOs are known to carry out many functions in plants and humans. In this paper, we provide a comprehensive review of RFOs, including their beneficial and anti-nutritional properties. RFOs are considered anti-nutritional factors since they cause flatulence in humans and animals. Flatulence is the single most important factor that deters consumption and utilization of legumes in human and animal diets. In plants, RFOs have been reported to impart tolerance to heat, drought, cold, salinity, and disease resistance besides regulating seed germination, vigor, and longevity. In humans, RFOs have beneficial effects in the large intestine and have shown prebiotic potential by promoting the growth of beneficial bacteria reducing pathogens and putrefactive bacteria present in the colon. In addition to their prebiotic potential, RFOs have many other biological functions in humans and animals, such as anti-allergic, anti-obesity, anti-diabetic, prevention of non-alcoholic fatty liver disease, and cryoprotection. The wide-ranging applications of RFOs make them useful in food, feed, cosmetics, health, pharmaceuticals, and plant stress tolerance; therefore, we review the composition and diversity of RFOs, describe the metabolism and genetics of RFOs, evaluate their role in plant and human health, with a primary focus in grain legumes.

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Grain legumes are a key food source for ensuring global food security and sustaining agriculture. However, grain legume production is challenged by growing disease incidence due to global climate change. Ascochyta blight (AB) is a major disease, causing substantial yield losses in grain legumes worldwide. Harnessing the untapped reserve of global grain legume germplasm, landraces, and crop wild relatives (CWRs) could help minimize yield losses caused by AB infection in grain legumes. Several genetic determinants controlling AB resistance in various grain legumes have been identified following classical genetic and conventional breeding approaches. However, the advent of molecular markers, biparental quantitative trait loci (QTL) mapping, genome-wide association studies, genomic resources developed from various genome sequence assemblies, and whole-genome resequencing of global germplasm has revealed AB-resistant gene(s)/QTL/genomic regions/haplotypes on various linkage groups. These genomics resources allow plant breeders to embrace genomics-assisted selection for developing/transferring AB-resistant genomic regions to elite cultivars with great precision. Likewise, advances in functional genomics, especially transcriptomics and proteomics, have assisted in discovering possible candidate gene(s) and proteins and the underlying molecular mechanisms of AB resistance in various grain legumes. We discuss how emerging cutting-edge next-generation breeding tools, such as rapid generation advancement, field-based high-throughput phenotyping tools, genomic selection, and CRISPR/Cas9, could be used for fast-tracking AB-resistant grain legumes to meet the increasing demand for grain legume-based protein diets and thus ensuring global food security.

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BACKGROUND: Dehulling and splitting are important elements of the milling process to produce dhal from pulses. However, grain that is difficult-to-mill because of tightly adhered seed coats or cotyledons that resist separation makes it difficult to achieve high quality dhal. Milling yields are reduced, energy inputs into the milling process are increased, and the resulting dhal can be of poorer quality, chipped or abraded. RESULTS: Eight enzyme pre-treatments were chosen based on the hypothesised mechanisms of seed coat and cotyledon adhesion established previously. Using a difficult-to-mill chickpea (Cicer arietinum L.) genotype, we examined the effects of these pre-treatments, over time, on laboratory-scale milling performance and dhal quality. We pioneered a texture analyser method to measure the flex of the cotyledons and the force required to cleave the cotyledons. The enzyme-induced changes ranged from negative (tough seed coat, weight loss, deleterious colour and texture, increased visual damage to cotyledons and increased kibble loss, concave cotyledons, increased flex, and changes in taste) to positive (brittle seed coat, increased seed volume, improved dehulling efficiency and splitting yield, reduced cotyledon cleavage force, and acceptable dhal quality and taste). CONCLUSION: All pre-treatments improved milling performance compared to milling the raw seed, although there was considerable variation between them. Two pre-treatments showed no improvement in milling yields compared to the water control, and several pre-treatments resulted in unacceptable qualities. Three pre-treatments, endo-polygalacturonanase, α-galactosidase and cellulase, show potential for commercial milling applications and could assist pulse millers globally to achieve high quality dhal at the same time as minimising milling effort. © 2021 Society of Chemical Industry.

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Several species of nematodes are known to cause losses to cowpea (Vigna unguiculata) throughout the world. In Brazil, Aphelenchoides besseyi was described as causing damage on soybean, cotton, and common bean, but no report was found about the parasitism of this nematode in cowpea. This study aimed to verify the host reaction of cowpea cultivars to A. besseyi. The experiment was conducted under greenhouse conditions, using two A. besseyi populations as inocula, obtained from symptomatic soybean and cotton plants collected in naturally infested fields. Cultivars Imponente, Aracê, Guariba, Tumucumaque, Nova Era, and Tracuateua were inoculated with 500 A. besseyi of each population, separately, into soil, and after 30 days from the inoculation nematodes were extracted from shoot systems. Both populations were able to parasitize all the cowpea cultivars. Independently of the cultivar, cowpea plants exhibited symptoms of leaf deformation similar to those described for soybean, cotton, and common bean and, in addition, severe brooming was observed, with the interior of the stems being porous and necrotic. To our knowledge, this is the first report of parasitism by A. besseyi of cowpea in Brazil, under greenhouse conditions, increasing the list of hosts of this nematode.

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BACKGROUND: Lupins are promising protein crops with an increasing amount of genomic and transcriptomic resources. The new resources facilitate the in silico identification of candidate genes controlling important agronomic traits. However, a major bottleneck for lupin research and crop improvement is the in planta characterization of gene function. Here, we present an efficient protocol for virus-induced gene silencing (VIGS) to down-regulate endogenous genes in narrow-leafed lupin (NLL) using the apple latent spherical virus (ALSV). RESULTS: We identified ALSV as an appropriate VIGS vector able to infect NLL without causing a discernible phenotype. We created improved ALSV vectors to allow for efficient cloning of gene fragments into the viral genome and for easier viral propagation via agroinfiltration of Nicotiana benthamiana. Using this system, we silenced the visual marker gene phytoene desaturase (PDS), which resulted in systemic, homogenous silencing as indicated by bleaching of newly produced tissues. Furthermore, by silencing lysine decarboxylase (LaLDC)-a gene likely to be involved in toxic alkaloid biosynthesis-we demonstrate the applicability of our VIGS method to silence a target gene alone or alongside PDS in a 'PDS co-silencing' approach. The co-silencing approach allows the visual identification of tissues where silencing is actively occurring, which eases tissue harvesting and downstream analysis, and is useful where the trait under study is not affected by PDS silencing. Silencing LaLDC resulted in a ~ 61% or ~ 67% decrease in transcript level, depending on whether LaLDC was silenced alone or alongside PDS. Overall, the silencing of LaLDC resulted in reduced alkaloid levels, providing direct evidence of its involvement in alkaloid biosynthesis in NLL. CONCLUSIONS: We provide a rapid and efficient VIGS method for validating gene function in NLL. This will accelerate the research and improvement of this underutilized crop.

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There is increasing interest in using locally produced protein supplements in dairy cow feeding. The objective of this experiment was to compare rapeseed meal (RSM), faba beans (FBs) and blue lupin seeds (BL) at isonitrogenous amounts as supplements of grass silage and cereal based diets. A control diet (CON) without protein supplement was included in the experiment. Four lactating Nordic Red cows were used in a 4 × 4 Latin Square design with four 21 d periods. The milk production increased with protein supplementation but when expressed as energy corrected milk, the response disappeared due to substantially higher milk fat concentration with CON compared to protein supplemented diets. Milk protein output increased by 8.5, 4.4 and 2.7% when RSM, FB and BL were compared to CON. The main changes in rumen fermentation were the higher propionate and lower butyrate proportion of total rumen volatile fatty acids when the protein supplemented diets were compared to CON. Protein supplementation also clearly increased the ruminal ammonia N concentration. Protein supplementation improved diet organic matter and NDF digestibility but efficiency of microbial protein synthesis per kg organic matter truly digested was not affected. Flow of microbial N was greater when FB compared to BL was fed. All protein supplements decreased the efficiency of nitrogen use in milk production. The marginal efficiency (amount of additional feed protein captured in milk protein) was 0.110, 0.062 and 0.045 for RSM, FB and BL, respectively. The current study supports the evidence that RSM is a good protein supplement for dairy cows, and this effect was at least partly mediated by the lower rumen degradability of RSM protein compared to FB and BL. The relatively small production responses to protein supplementation with simultaneous decrease in nitrogen use efficiency in milk production suggest that economic and environmental consequences of protein feeding need to be carefully considered.

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BACKGROUND: Soybeans (Glycine max) are a major protein source both for humans and non-ruminant livestock; however, the usability of soybean protein is limited by the concentration of the essential sulfur (S)-containing amino acids methionine and cysteine (MET+CYS). Traditional efforts to improve protein quality in soybeans have largely been focused on plant breeding but soil S fertility may also influence seed MET+CYS concentration. Crop S deficiencies are increasingly common due to soil depletion by high yields and reduced atmospheric deposition. We report on a survey of commercial soybean fields and two replicated split-plot field experiments in the mid-Atlantic region, USA. The experimental treatments were two levels (0 or 100 kg S ha-1 ) of broadcast gypsum (CaSO4 ) and two levels (0 or 11 kg-S ha-1 ) of foliar Epsom salt (MgSO4 ) applied to two soybean cultivars. The objective was to assess the variability of, and effect of, S fertilization on S and MET+CYS concentrations in soybean seeds. RESULTS: Sulfur ranged from 2.35 to 3.54 mg g-1 and MET+CYS ranged from 5.5 to 9.2 mg g-1 protein in seeds from commercial fields surveyed. Sulfur application increased seed MET+CYS concentration 1.3 to twofold in two replicated field experiments. Overall, MET+CYS concentration in protein ranged from 3.9 to 12.8 mg g-1 and was linearly predicted (R2  = 0.65) by seed S. CONCLUSIONS: Soybean seed S and MET+CYS concentrations vary widely. We show that field-scale S application can greatly enhance soybean MET+CYS content and therefore protein quality. © 2021 Society of Chemical Industry.

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The underutilised grain legume bambara groundnut (Vigna subterranea) has the potential to contribute significantly to nutritional security. However, the lack of commercial cultivars has hindered its wider adoption and utilisation as a food source. The development of competitive cultivars is impeded by (1) lack of systematic data describing variation in nutritional composition within the gene pool, and (2) a poor understanding of how concentrations of different nutritional components interact. In this study, we analysed seed lipid and protein concentration and lipid composition within a collection of 100 lines representing the global gene pool. Seed protein and lipid varied over twofold with a normal distribution, but no significant statistical correlation was detected between the two components. Seed lipid concentration (4.2-8.8 g/100 g) is primarily determined by the proportion of oleic acid (r2 = 0.45). Yield and composition data for a subset of 40 lines were then used to test selection parameters for high yielding, high lipid breeding lines. From five selection indices tested using 15 scenarios, an index based on the seed number, seed weight, and oleic acid yielded a >50% expected increase in each of the mean values of seed number, pod dry weight, seed dry weight, and seed size, as well as an expected 7% increase in seed lipid concentration.

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Legume plants, such as peas, are of significant nutritional interest for both humans and animals. However, plant nutrition and thus, seed composition, depends on soil mineral nutrient availability. Understanding the impact of their deprivation on the plant mineral nutrient content, net uptake, and remobilization is of key importance but remains complex as the elements of the plant ionome are linked in intricate networks, one element deprivation impacting uptake and remobilization of other nutrients. To get a better insight into pea mineral nutrition, the transitory deprivations of 13 mineral nutrients were imposed during the vegetative growth phase. Thereafter, plants were grown under optimal mineral conditions until physiological maturity. Plant nutritional status and seed quality impacts caused by the deprivations were characterized using measurement of mineral nutrient concentration and plant biomass allocation. Our results highlight: (i) the preferential allocation of dry weight and elements to shoots at the expense of the roots under non-limiting conditions, and more particularly to the tendrils in comparison to the other shoot organs, (ii) the positive and/or negative impact of one mineral nutrient deprivation on other elements of the ionome, (iii) four different remobilization strategies for eight mineral nutrients, and (iv) possible strategies to improve seed quality via fine control of fertilization during a period of mineral nutrient deficiency.

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Fusarium wilt (FW) disease is the key constraint to grain legume production worldwide. The projected climate change is likely to exacerbate the current scenario. Of the various plant protection measures, genetic improvement of the disease resistance of crop cultivars remains the most economic, straightforward and environmental-friendly option to mitigate the risk. We begin with a brief recap of the classical genetic efforts that provided first insights into the genetic determinants controlling plant response to different races of FW pathogen in grain legumes. Subsequent technological breakthroughs like sequencing technologies have enhanced our understanding of the genetic basis of both plant resistance and pathogenicity. We present noteworthy examples of targeted improvement of plant resistance using genomics-assisted approaches. In parallel, modern functional genomic tools like RNA-seq are playing a greater role in illuminating the various aspects of plant-pathogen interaction. Further, proteomics and metabolomics have also been leveraged in recent years to reveal molecular players and various signaling pathways and complex networks participating in host-pathogen interaction. Finally, we present a perspective on the challenges and limitations of high-throughput phenotyping and emerging breeding approaches to expeditiously develop FW-resistant cultivars under the changing climate.

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The ability to adapt to a novel host plant may vary among insect populations with different genetic histories, and colonization of a marginal host may be facilitated by genetic admixture of disparate populations. We assembled populations of the seed beetle, Callosobruchus maculatus (F.), from four continents, and compared their ability to infest two hosts, lentil and pea. We also formed two cross-continent hybrids (Africa × N.A. and Africa × S.A.). In pre-selection assays, survival was only ~3% in lentil and ~40% in pea. For three replicate populations per line, colonization success on lentil was measured as cumulative exit holes after 75-175 d. On pea, we estimated the change in larval survival after five generations of selection. Females in all lines laid few eggs on lentil, and survival of F1 larvae was uniformly <5%. Subsequently, however, the lines diverged considerably in population growth. Performance on lentil was highest in the Africa × N.A. hybrid, which produced far more adults (mean > 11,000) than either parental line. At the other extreme, Asian populations on lentil appeared to have gone extinct. The Africa × N.A. line also exhibited the highest survival on pea, and again performed better than either parent line. However, no line displayed a rapid increase in survival on pea, as is sometimes observed on lentil. Our results demonstrate that geographic populations can vary substantially in their responses to the same novel resource. In addition, genetic admixtures (potentially caused by long-distance transport of infested seeds) may facilitate colonization of an initially poor host.

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The impacts of rhizobium inoculation on growth and yield of chickpea have mainly been tested in experiments conducted in greenhouses or on research stations. We report the response of the crop to inoculation (I) and phosphorus fertilizer (P) application across a large number of smallholder's farms over four regions of Ethiopia, covering diverse soil fertility and agro-ecological conditions. Increased grain yields due to the soil fertility treatments was evident for 99% target farmers. On average, I and P increased grain yield by 21% and 25% respectively, while the combined application of I and P resulted in a 38% increase. However, observed grain yields on control plots and responses to the treatments on individual farms varied greatly, and relative yield responses (%; yield of P and/I minus control yield, divided by control yield) ranged from 3% to 138%. With the exception of a few extremely poorly yielding locations, average responses to P and I were high across a wide range of control yields, indicating the possibility of boosting chickpea productivity for smallholders with P fertilizer and inoculant technology. Variation in response to rhizobium inoculation was mostly independent of agro-ecology and soil type although it was found to be low on a number of farms with extremely high N contents (%). Assuming that a relative yield increase of 10% due to treatment effects is required to be visible, 71%, 73% and 92% of the farmers observed a yield benefit by applying P, I, and P + I, respectively. The results are discussed with respect to the additive benefits of P fertilizers and rhizobial inoculation and their implications for wide scale promotion of inoculant technology to smallholders.