Leguminous Forage Research Articles

Physiological, biochemical, and transcriptional regulation in a leguminous forage Trifolium pratense L. responding to silver ions

Trifolium pratense L. (red clover) is an important leguminous crop with great potential for Ag-contaminated environment remediation. Whereas, the molecular mechanisms of Ag tolerance in red clover are largely unknown. Red clover seedlings were used for physiological and transcriptomic investigation under 0, 20, 50, and 100 mg/L Ag+ stress in our research to reveal potential molecular resistance mechanism. Research showed that red clover possessed fairly strong Ag absorbance capacity, the Ag level reached 0.14 and 2.35 mg/g·FW in the leaves and roots under 100 mg/L AgNO3 stress condition. Root fresh weight, root dry weight, root water content, and photosynthetic pigments contents were significantly decreased with elevating AgNO3 concentration. Obvious withered plant tissue, microstructure disorder, and disrupted organelles were observed. In vitro evaluations (e.g., PI and DCFH-DA staining) represented that AgNO3 at high concentration (100 mg/L) exhibited obvious inhibition on cell viability, which was due possibly to the induction of reactive oxygen species (ROS) accumulation. A total of 44643 differentially expressed genes (DEGs) were identified under Ag stress, covering 27155 upregulated and 17488 downregulated genes. 12 stress-responsive DEGs was authenticated utilizing real-time quantitative PCR (qRT-PCR). Gene ontology (GO) analysis revealed that the DEGs were mostly related to metal ion binding (molecular function), nucleus (cellular component), and defense response (biological process). Involved DEGs in sequence-specific DNA binding transcription factor activity, response to various hormones (e.g., abscisic acid, IAA/Auxin, salicylic acid, and etc), calcium signal transduction, and protein ubiquitination were concluded to play crucial roles in Ag tolerance of red clover. On the other hand, Kyoto Encyclopedia of Genes and Genomes (KEGG) database annotated several stress responsive pathways such as plant-pathogen interaction, phenylpropanoid biosynthesis, ubiquitin mediated proteolysis, hormone signal transduction, and autophagy. Several down-regulated genes (e.g., RSF2, RCD1, DOX1, and etc) were identified indicating possible metabolic disturbance. Besides, protein-protein interaction network (PPI) identified several pivotal genes such as ribosomal proteins, TIR, and ZAT.

The complete chloroplast genome of Securigera varia (L.) Lassen

Securigera varia is an important leguminous forage grass species that is mainly distributed in arid and semi-arid land with water scarcity, and has outstanding drought resistance. In this study, Illumina sequencing was used to obtain the complete sequence of the S. varia chloroplast genome. The complete genome was 154,257 bp in length with 35.9% GC content. It was a circular genome containing a large single-copy region (LSC, 84,762 bp), a small single-copy region (SSC, 18,059 bp), and a pair of inverted repeat regions (IRs, 51,436 bp). A total of 128 genes were encoded, including 83 protein-coding genes, 37 tRNAs, and 8 rRNAs. Phylogenetic analysis revealed that S. varia was closely related to Robinia pseudoacacia. The sequence data of S. varia chloroplast genome could provide useful genetic information for the studies on phylogenetic and evolutionary of Leguminosae.

Characterization of Curvularia buchloes causing leaf spots on Medicago sativa L. (alfalfa) and its management through fungicides

Medicago sativa L. (alfalfa) is a perennial leguminous forage crop cultivated worldwide. Unique water-soaked brown spots surrounded by yellow haloes were reported extensively on leaves of alfalfa crop from the farmer fields of Hafizabad and Bahawalpur districts in 2018. Olive gray colonies of a fungus, isolated with 95% frequency from the symptomatic tissues, were identified as Curvularia sp. based on morphocultural characteristics. Thus, representative Curvularia isolate “FMB-ALF2-MS” was subjected to molecular analysis to validate its phylogeny. Four genetic regions, ITS, LSU, TEF1-α, and GAPDH, were directly sequenced. BLASTn search showed 100% homology to C. buchloes strain CBS 246.49. Phylogenetic analysis is also identified and congruent with this isolate as C. buchloes with 100% bootstrap support. Four repeated pathogenicity tests were carried out with C. buchloes, and the etiology of the leaf spots was determined. To our best knowledge, this is the first report of C. buchloes causing leaf spots on alfalfa from Pakistan. The new and emerging foliar disease's occurrence and intensity were documented across the Punjab province during 2018–2019. The highest D.I (57%) with an average D.S of 78.5% was recorded from the Bahawalpur district. Eight different (four contact and four systemic) fungicides were tested against the pathogen under in vitro conditions at 50, 100, 150, and 200 ppm concentration. Among all the tested fungicides, maximum inhibition (95%) was recorded through mancozeb (contact fungicide), followed by 92% pathogen growth inhibition through propiconazole (systemic fungicide) at 200 ppm. Characterized pathogenic fungal isolate was deposited to the Culture Collection (FMB-CC-UAF) with accession number FMB0177.

Heterogeneous expression of Osa-MIR156bc increases abiotic stress resistance and forage quality of alfalfa

Alfalfa (Medicago sativa L.) is the most widely cultivated perennial leguminous forage crop woldwide. MicroRNA156 (miR156) precursor genes from dicotyledonous species are reportedly useful for improving alfalfa plant architecture and abiotic stress resistance. However, there has been no report on whether a miR156 precursor gene from a monocotyledonous species functions in alfalfa. We introduced two tandem precursor genes of miR156, rice Osa-MIR156b and Osa-MIR156c (Osa-MIR156bc), into alfalfa. The expression of miR156 in the transgenic (TG) alfalfa was significantly elevated. Compared to wild-type plants, the TG plants overexpressing miR156 had more branches and leaves and showed improved salt and drought tolerance. Overexpression of miR156 slightly reduced plant height, but the biomass yield of TG plants grown in flowerpots was still increased. Forage quality of TG plants was markedly improved by reduction of acid detergent lignin (ADL) content and increase in crude protein content. The expression of the putative miR156 target genes MsSPL6, MsSPL12, and MsSPL13 in TG plants was repressed by miR156 overexpression, and that of all tested MsSPLs would be sharply increased under drought or salt stress. RNA sequencing revealed that overexpression of miR156 affected the expression of genes associated with abiotic stress resistance and plant development in multiple pathways. This first report of overexpression of monocot miR156 precursors in alfalfa sheds light on the function of miRNA156 precursors from the monocot species rice that could be used for genetic improvement of the dicot forage crop alfalfa.

Selection of an optimal method for screening the collection of narrow-leaved lupine held by the Vavilov Institute for the qualitative and quantitative composition of seed alkaloids.

Narrow-leaved lupine (Lupinus аngustifolius L.) is a widely cultivated leguminous forage and green manure crop with a potential for human nutrition. However, the presence of secondary metabolites – alkaloids – in lupine seeds considerably affects the quality of raw produce, reducing its nutritive value; in addition, high concentrations of alkaloids are toxic to humans and animals. Therefore, plant breeders working with lupine need to gain knowledge about the variability of alkaloid content in seeds of different genotypes and search for the sources of their low concentrations in the crop’s gene pool. The collection of narrow-leaved lupine genetic resources held by the N.I. Vavilov Institute of Plant Genetic Resources (VIR) offers wide opportunities for such search by means of mass screening. For its part, largescale gene pool screening requires the selection of an optimal technique to measure alkaloid content in seeds, so that it would be easily reproducible and as little labor-, time- and fund-consuming as possible. The results of the search for such method are presented. Qualitative and quantitative indices were compared when target compounds had been extracted with multicomponent mixtures and individual reagents (chloroform, methanol, etc.) and the extracts analyzed using gas chromatography-mass spectrometry. High-performance liquid chromatography combined with mass spectrometry was also employed. Five major alkaloids were found to be present in all types of extracts: lupanine, 13-hydroxylupanine (dominant ones), angustifoline, sparteine, and isolupanine. The fullest extraction of alkaloids was observed when the extractant with an added alkaline agent was used (425 mg/100 g). The lowest level of extraction was registered with chloroform (216 mg/100 g). The significance of the differences was confirmed statistically

Multiple agroecosystem services of forage legumes towards agriculture sustainability: An overview

Forage legumes are contributing in sustainable crop production apart from nutritional security to the livestock. Forage legumes are crucial for the nutritional security for mankind as they are integral component for increased availability of animal protein and product which has higher biological value compared to plant proteins. The inclusion of forage legumes in crop production systems is more useful as these can not only provide food and feed to animals but also improves soil productivity and act as soil-conserving components of agricultural and agroforestry systems. Production system as a whole and tremendous deficit of forage nutritious resources demand in particular to give some importance to the forage crops especially leguminous forages. Therefore, critical assessment is necessary for determining the direction and magnitude of change in agricultural management practice with inclusions of forage legume. Forage legumes have good capacity as a feed to promote sufficient quantities and qualities required for different productive animals. Therefore, these crops can contribute to achieving the objectives of sustainable food/ fodder and environmental security. Hence, inclusion of legumes forages in cropping system is inevitable in advancing soil sustainability and food and nutritional security without compromising the long-term soil fertility base of the soil resources. Rational soil management practices must involve forage legume-based rotations and intercropping considerations for restoring soil health, and soil sustainability should be given due emphasis. Besides, forage legumes can also provide a wide range of benefits such as restoration of soil fertility, nitrogen fixation and fertilizer saving, enhancement of soil biology and biodiversity, improving soil carbon sequestration and by neutralizing negative impact of climate change. This review summarizes the potential role of forage legume in animal nutrition, soil fertility building, nitrogen fixation, soil biology and biodiversity, carbon sequestration, climate change and other ecological services provided.

Effects of Ensiling Oxytropis glabra with Whole-Plant Corn at Different Proportions on Fermentation Quality, Alkaloid Swainsonine Content, and Lactic Acid Bacteria Populations.

Simple SummaryIn Inner Mongolia, developing innovative forages is an indispensable way to ease the shortage of animal feed. Oxytropis glabra (OG) has become a dominant population, with a high nature yield in the degraded grassland of Inner Mongolia. As a typical legume, it is rich in amino acids and trace elements, so using OG to feed livestock is a valuable strategy. However, it contains swainsonine (SW), which hinders the utilization of OG. This study was conducted to evaluate silage fermentation and SW removal from OG ensiled with whole-plant corn at different proportions, and the result showed ensiling a mixture of OG and corn could be a valuable approach for producing livestock feed, as it had a positive effect on fermentation quality and SW detoxification; the optimal ratio was 1:1. In the silages, Lactobacillus plantarum was the most common microorganism present in all mixture silages, and Lactobacillus amylovorus and Lactobacillus brevis were prevalent at lower ratios of corn to OG. All representative strains were able to remove SW from OG fermentation, and the strains of L. amylovorus and L. plantarum had a higher SW removal rate. These mixtures of silages could make OG useable as a feed source in ruminant production.Oxytropis glabra (OG) is a leguminous forage that is potentially valuable for solving the shortage of feed for livestock production, while, in large quantities, it may be toxic because of its swainsonine (SW) content. In this study, OG was ensiled with whole-plant corn (Zea mays L.) at 10:0, 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, and 0:10 ratios on a fresh matter basis, and, after 60 d of ensiling, the chemical composition, fermentation characteristic, SW removal rate, lactic acid bacteria (LAB) populations, and their capabilities for SW removal were analyzed. As the proportion of corn in the silage increased, the pH, as well as the propionic acid, ammonia-N, dry matter, crude protein, and SW contents, decreased linearly, while the lactic acid, neutral detergent fiber, and residual water-soluble carbohydrate contents increased linearly. Lactobacillus plantarum was the most common microorganism present in all mixture silages. Lactobacillus amylovorus and Lactobacillus brevis were prevalent at lower ratios of corn to OG. Meanwhile, the LAB strains belong to L. amylovorus and L. plantarum had a higher SW removal rate. Our results suggested that ensiling OG with whole-plant corn improves fermentation and decreases SW content, and that 5:5 is the optimal ratio, so this type of mixed silage could make OG useable for ruminant production.

The differences and overlaps in the seed-resident microbiome of four Leguminous and three Gramineous forages.

SummaryGiven the important roles that seed‐borne endophytes can play on their plant hosts, comprehensive studies of the bacterial and fungal communities of seeds are of great importance. In this study, we assessed the seed endophytes of three gramineous (Avena sativa, Elymus sibiricus and Elymus dahuricus) and four leguminous (Vicia villosa, Trifolium repens, Trifolium pretense and Medicago sativa) forages using high‐throughput sequencing. In total, 1013 distinct bacterial operational taxonomic units (OTUs) and 922 fungal OTUs were detected, with bacteria and fungi per sample ranging from 240 to 425 and 261 to 463 respectively. These seven forages shared a high number of potentially beneficial taxa, including Bacillus, Pantoea, Candida and Helotiales, but the relative proportion of these taxa was different in each seed. Fungal communities were clustered more distinctively by host genotypes than bacterial. Some bacterial taxa may be involved in the recruitment of genera from the same phylum. Three Pantoea sp. and five Bacillus sp. were isolated from seeds, and all showed positive effects on Medicago sativa germination rate under salt stress, and of these, Bacillus subtilis Es‐1 and Pantoea agglomerans Ed‐3 performed best, but their influence was affected by the seed’s microbiome. Rather than simply promoting host plant growth directly, some taxa may also participate in organizing the assembly of plant microbiomes which will influence seed response to biological factors. This study uses a new, high‐throughput sequencing based strategy to identify beneficial strains and analyse the interactions between microorganisms and plants to maximize microbial functions in long‐term agricultural practices.

Tropical forage technologies can deliver multiple benefits in Sub-Saharan Africa. A meta-analysis

Scarcity of quantity and quality feed has been a key constraint to productivity of smallholder crop-livestock systems. Tropical forages include a variety of annual and perennial grasses, herbaceous and dual-purpose legumes, and multipurpose trees and shrubs. They have been promoted in Sub-Saharan Africa (SSA) for increasing livestock productivity and household income through higher quantity and quality of herbage, while contributing to soil improvement and higher food crop yields. For the first time, we quantitatively reviewed 72 experimental studies from across SSA to take stock of geographical distribution and forage technology focus of past research; quantify magnitudes of multidimensional impacts of forage technologies; and present variability in forage agronomy data. Improved forage technologies were classified into four groups: (i) germplasm, (ii) management, (iii) cropping system integration, and (iv) feeding regime. Mean weighted response ratios were calculated from 780 pairs of observations for 13 indicators across the five impact dimensions. Improved forage germplasm had on average 2.6 times higher herbage productivity than local controls, with strongest effect in grasses. Feeding regimes with improved leguminous forages increased milk yield by on average 39%, dry matter intake by 25%, and manure production by 24%. When forage technologies were integrated with food crops, soil loss was almost halved, soil organic carbon increased on average by 10%, and grain and stover yields by 60% and 33%, respectively. This study demonstrates the central role improved forages could play in sustainable intensification of crop-livestock systems in SSA. It highlights the need for multidisciplinary and systems-level approaches and studies to quantify synergies and tradeoffs between impact dimensions. Further research is needed to explain forage agronomic yield variability, unraveling interactions between genotype, on-farm environmental conditions, and management factors. Results from this review can inform development programs, prioritizing technologies proven successful for dissemination and indicating magnitudes of expected impacts.

Forge yield and its quality of sudangrass and cowpea under different intercropping patterns

The objective of this study is to evaluate the effect of different intercropping patterns of sudangrass (a cereal forage) and cowpea (a leguminous forage) on forage yield and its quality. Two field experiments were carried out during 2018 and 2019 seasons at Sakha, Agricultural Research Station, Kafr El-Sheakh, Agriculture Research Center (ARC), Giza, Egypt, to study the forage yield and quality of sudangrass and cowpea under different intercropping patterns, i.e. (100% sudangrass+25% cowpea; 100% sudangrass+ 50% cowpea, 100% sudangrass+75% cowpea, 100% sudangrass+100% cowpea, 75% sudangrass+25% cowpea, 50% sudangrass+50% cowpea and 25% sudangrass+75% cowpea) of seeding rate per feddan, of sudangrass and cowpea compared to sole stands of both crops. Treatments were laid out in a randomized complete block design with three replications. The obtained results showed that, 100% sudangrass + 75% cowpea (P3 treatment) gave the highest values yield/fed (fresh and dry yields). There was an increasing in mixed cowpea plants [25% sudangrass + 75% cowpea (P7) recorded the highest (CP%)], while increasing sudangrass in mixed of 100% sudangrass + 100% cowpea (P4) recorded the highest (CF%). 100% sudangrass + 75% cowpea (P3) gave the highest values of the land equivalent ratio (LER), relative crowding coefficient (K) and net return. The best intercropping pattern of 100% sudangrass + 75% cowpea (P3) which was significantly the highest forage productivity and quality, land equivalent ratio (LER), relative crowding coefficient (K), aggressivity and net return.

Identification of Heat-Responsive Genes in Guar [Cyamopsis tetragonoloba (L.) Taub

The threat of heat stress on crop production increased dramatically due to global warming leading to the rise on the demand of heat-tolerant crops and understanding their tolerance. The leguminous forage crop Guar [Cyamopsis tetragonoloba (L.) Taub] is a high-temperature tolerant plant with numerous works on its tolerance at morph-physiological levels but lack on molecular thermotolerance level. In the current study, the differential gene expression and the underlying metabolic pathways induced by heat treatment were investigated. An RNA-Seq study on Guar leaves was carried out to estimate gene abundance and identify genes involved in heat tolerance to better understand the response mechanisms to heat stress. The results uncovered 1551 up- and 1466 downregulated genes, from which 200 and 72 genes with unknown function could be considered as new genes specific to guar. The upregulated unigenes were associated with 158 enzymes and 102 KEGG pathways. Blast2GO, InterProScan, and Kyoto Encyclopaedia of Genes and Genomes packages were utilized to search the functional annotation, protein analysis, enzymes, and metabolic pathways and revealed hormone signal transduction were enriched during heat stress tolerance. A total of 301 protein families, 551 domains, 15 repeats, and 3 sites were upregulated and matched to those unigenes. A batch of heat-regulated transcription factor transcripts were identified using the PlantTFDB database, which may play roles in heat response in Guar. Interestingly, several heat shock protein families were expressed in response to exposure to stressful conditions for instance small HSP20, heat shock transcription factor family, heat shock protein Hsp90 family, and heat shock protein 70 family. Our results revealed the expressional changes associated with heat tolerance and identified potential key genes in the regulation of this process. These results will provide a good start to dissect the molecular behaviour of plants induced by heat stress and could identify the key genes in stress response for marker-assisted selection in Guar and reveal their roles in stress adaptation in plants.

Effect of intercropping on growth and yield of some Leguminous and Cereal forage crops in El Kadaru Area

Intercropping is not a common practice in forage production in Sudan, in spite of its importance; farmers don’t know the potentiality of this type of cultivation and more experiments needed to adopt this type of cropping system and it is an example of biological interaction. A field experiment was conducted under irrigation for two consecutive seasons during 2013-2014 and 2015-2016 in the demonstration farm, college of Animal production, University of Bahri, Sudan to study the effect of intercropping of two leguminous forage crops (clitoria and phillipesara) cultivated with one non leguminous crop (Sorghum). Randomized complete block design (RCBD) was used. Yield of sole crops produced more forage, but the total yield (Over yielding) of the intercropped plants as revealed by land equivalent ratio was higher compared with the individual crops. Clitoria growth parameters (plant height, number of leaves and stem diameter) were not significantly affected by intercropping, but there was significant difference in plant population in the two seasons. Intercropping did not significantly affect growth parameters during the two seasons of Phillipesara except plant population and the first reading of plant height. Sorghum showed significant differences in plant population and some readings during the two seasons (the fourth reading of plant height in the first season, the first reading of number of leaves in first season, the fourth reading of stem diameter in the first season and the first reading of stem diameter in the second season).

Overexpression of MsASMT1 Promotes Plant Growth and Decreases Flavonoids Biosynthesis in Transgenic Alfalfa (Medicago sativa L.).

Melatonin (N-acetyl-5-methoxytryptamine) is a pleiotropic signaling molecule that plays important roles in plant growth, development and stress responses. Alfalfa (Medicago sativa L.) is an important and widely cultivated leguminous forage crop with high biomass yield and rich nutritional value. The effects of exogenous melatonin content regulation on alfalfa stress tolerance have been investigated in recent years. Here, we isolated and introduced the MsASMT1 (N-acetylserotonin methyltransferase) gene into alfalfa, which significantly improved the endogenous melatonin content. Compared with wild-type (WT) plants, MsASMT1 overexpression (OE-MsASMT1) plants exhibited a series of phenotypic changes, including vigorous growth, increased plant height, enlarged leaves and robust stems with increased cell sizes, cell numbers and vascular bundles, as well as more branches. We also found that the flavonoid content and lignin composition of syringyl to guaiacyl ratio (S/G) were decreased and the cellulose content was increased in OE-MsASMT1 transgenic alfalfa. Further transcriptomic and metabolomic exploration revealed that a large group of genes in phenylalanine pathway related to flavonoids and lignin biosynthesis were significantly altered, accompanied by significantly reduced concentrations of the glycosides of quercetin, kaempferol, formononetin and biochanin in OE-MsASMT1 transgenic alfalfa. Our study first uncovers the effects of endogenous melatonin on alfalfa growth and metabolism. This report provides insights into the regulation effects of melatonin on plant growth and phenylalanine metabolism, especially flavonoids and lignin biosynthesis.

Restricting lepidopteran herbivory through trap cropping and bird perches in Egyptian clover (Trifolium alexandrinum L.)

The Egyptian clover L. is a winter season leguminous forage that supports a great diversity of insect pest populations in the Northern Indian Plains. In the context of evolving non-chemical approach for pest control, different trap crops viz. marigold, Tagetes erecta: chickpea, Cicer arietinum L.; and sunflower, Helianthus annuus, were planted as border rows around the clover plots to trap lepidopteran larvae. The push and pull strategy was further augmented by the help of neem seed kernel extract (NSKE) 3% spray on the main crop. Services of insectivorous birds were utilized through T-shaped bird perches for feeding on lepidopteran larvae. The lowest larval population of Helicoverpa armigera (2.29 individuals/m row length) was recorded in the plots with the trap crops such as marigold and bird perches, and those that received neem insecticidal sprays which indicated the decrease of larval population due to the repellant action of neem gave (75.8%) a reduction in larval population than the sole cropped plots, followed by chickpea (2.58 larvae; 72.8%) reduction in larval population and sunflower (3.53 larvae; 63%). Sunflower recorded the highest number of H. armigera population, at flowering stage of berseem which depicted the suitability of sunflower for the attractiveness of low number of the larvae (2.75 larvae/m row length) on berseem. The plots with berseem as a sole crop without any control measure exhibited significantly high H. armigera larvae (12.95 larvae per meter row length). The fecundity of pod borer on different trap crops revealed the highest fecundity population (7.25 larvae) of Helicoverpa on either chickpea or sunflower as trap crops. During the vegetative phase of berseem and the flowering stage of marigold and sunflower, these were recorded as favorable hosts. The highest green fodder yield (GFY; 1115 q/ha) was recorded in plots sown with marigold as the trap crop and with bird perches and in plots that received NSKE sprays as compared to sole cropped plots (700 q/ha). The data on seed yield also revealed superiority of berseem plots with sunflower, as a trap crop, and also a high parasitization by parasitoids.

Effects of oat hay and leguminous forage mixture feeding on enteric methane emission, energy utilization, and feed conversion efficiency in male crossbred Simmental beef cattle.

Dietary manipulation has the potential to mitigate methane (CH4 ) emission and to maintain or enhance livestock productivity. We conducted two experiments to investigate the effects of replacing oat hay by leguminous forages (alfalfa hay [AH], 0, 8, 16, and 24%, experiment 1; common vetch hay [CVH], 0, 10, 20, and 30%, experiment 2) on energy metabolism of crossbred Simmental cattle. In experiment 1, total volatile fatty acid (VFA) concentrations increased quadratically with increasing AH proportions (p=.006) with a forage-to-concentrate ratio of approximately 50:50, whereas the CH4 energy to gross energy intake ratio (CH4 -E:GEI) was significantly lower with 16% AH compared with 24% AH diet (p<.05). In experiment 2, there were no differences in the total VFA concentrations among the four diet groups with a forage-to-concentrate ratio of around 60:40 (p>.05); however, CH4 -E:GEI was significantly lower in the 30% CVH diet compared with the 10% CVH diet (p<.05). There was no significant difference in feed conversion efficiency among the four diet groups in each experiment. The results suggest that substituting 16 and 30% oat hay by AH and CVH provide optimal diets with forage-to-concentrate ratios of 50:50 and 60:40, respectively, which may reduce CH4 emission without compromising the feed conversion efficiency of crossbred Simmental cattle.

Substitution of leguminous forage for oat hay improves nitrogen utilization efficiency of crossbred Simmental calves.

Low nitrogen (N) utilization efficiency (NUE, the ratio of retained N to N intake [NI]) of ruminants is always a potential dietary protein wastage as well as a global environmental problem, and dietary N manipulation is the most effective way to improve NUE. We conducted 2 experiments to investigate the effects of replacing oat hay by leguminous forages (alfalfa hay [AH] in experiment [Exp] 1 and common vetch hay [CVH] in Exp 2) with 4 levels (0%, 8%, 16% or 24% AH and 0%, 10%, 20% or 30% CVH on dry matter [DM] basis) at the same crude protein (135g/kg DM) and metabolizable energy (10.1MJ/kg DM) on feed intake, N metabolism, NUE and blood composition of crossbred Simmental calves. Sixteen calves of each Exp were assigned to the four diets in a randomized block design. Faecal N (FN) output and the ratio of FN to NI increased with increasing AH/CVH proportions, whereas urinary N (UN) output, the ratio of UN to NI, and the ruminal ammonia N concentration gradually decreased in both experiments. Nutrient digestibility (DM, organic matter [OM] and neutral detergent fibre [NDF]) of calves showed a parabolic trend with gradually increasing AH/CVH proportions. The highest values of nutrient digestibility (DM, OM and NDF) of calves were observed in 16% AH in Exp 1 and 20% CVH in Exp 2. Our findings suggest that 16% and 20% substitution (as a percentage of the total DM allowance) of AH and CVH, respectively, for oat hay are optimal diets to improve NUE and reduce the potential impact of N excretion from livestock farming on the environment through shifting routes of N from urine to faeces without negative effects on live weight gain and nutrient digestibility of crossbred Simmental calves in dryland environments.

Identification of Exogenous Nitric Oxide-Responsive miRNAs from Alfalfa (Medicago sativa L.) under Drought Stress by High-Throughput Sequencing.

Alfalfa (Medicago sativa L.) is a high quality leguminous forage. Drought stress is one of the main factors that restrict the development of the alfalfa industry. High-throughput sequencing was used to analyze the microRNA (miRNA) profiles of alfalfa plants treated with CK (normal water), PEG (polyethylene glycol-6000; drought stress), and PEG + SNP (sodium nitroprusside; nitric oxide (NO) sprayed externally under drought stress). We identified 90 known miRNAs belonging to 46 families and predicted 177 new miRNAs. Real-time quantitative fluorescent PCR (qRT-PCR) was used to validate high-throughput expression analysis data. A total of 32 (14 known miRNAs and 18 new miRNAs) and 55 (24 known miRNAs and 31 new miRNAs) differentially expressed miRNAs were identified in PEG and PEG + SNP samples. This suggested that exogenous NO can induce more new miRNAs. The differentially expressed miRNA maturation sequences in the two treatment groups were targeted by 86 and 157 potential target genes, separately. The function of target genes was annotated by gene ontology (GO) enrichment and kyoto encyclopedia of genes and genomes (KEGG) analysis. The expression profiles of nine selected miRNAs and their target genes verified that their expression patterns were opposite. This study has documented that analysis of miRNA under PEG and PEG + SNP conditions provides important insights into the improvement of drought resistance of alfalfa by exogenous NO at the molecular level. This has important scientific value and practical significance for the improvement of plant drought resistance by exogenous NO.

Diet and Genetics Influence Beef Cattle Performance and Meat Quality Characteristics.

A comprehensive review of the impact of tropical pasture grazing, nutritional supplementation during feedlot finishing and fat metabolism-related genes on beef cattle performance and meat-eating traits is presented. Grazing beef cattle on low quality tropical forages with less than 5.6% crude protein, 10% soluble starches and 55% digestibility experience liveweight loss. However, backgrounding beef cattle on high quality leguminous forages and feedlot finishing on high-energy diets increase meat flavour, tenderness and juiciness due to improved intramuscular fat deposition and enhanced mono- and polyunsaturated fatty acids. This paper also reviews the roles of stearoyl-CoA desaturase, fatty acid binding protein 4 and fatty acid synthase genes and correlations with meat traits. The review argues that backgrounding of beef cattle on Desmanthus, an environmentally well-adapted and vigorous tropical legume that can persistently survive under harsh tropical and subtropical conditions, has the potential to improve animal performance. It also identifies existing knowledge gaps and research opportunities in nutrition-genetics interactions aimed at a greater understanding of grazing nutrition, feedlot finishing performance, and carcass traits of northern Australian tropical beef cattle to enable red meat industry players to work on marbling, juiciness, tenderness and overall meat-eating characteristics.

First Report of Alfalfa Leaf Curl Virus Infecting Alfalfa (Medicago sativa) in China

Alfalfa (Medicago sativa L.) is one of the most important leguminous forage crops globally and has grown in importance in China with ∼4.72 million hectares in 2015. A previous study reported the occurrence of several common viruses (e.g., alfalfa mosaic virus [AMV], white clover mosaic virus, bean yellow mosaic virus, and cowpea mosaic virus) in alfalfa fields in China, in Anning District and Gaolan County of Lanzhou, and Jingtai County of Baiyin City, Gansu Province (Zhou et al. 2016). In April 2017 a survey was conducted to identify viruses infecting alfalfa in a temperate region: Yuanyang County, Henan Province (N35°01′, E113°43′). From one field, 117 alfalfa leaf samples with symptoms of macular mosaic (n = 26), mottle mosaic (21), etiolation (1), shrinkage (27), mosaic shrinkage (25), and dwarfism (17) were collected. Total RNA was extracted from a composite sample comprising six leaves exhibiting each above-mentioned symptom using an EASYspin Plant Micro RNA Rapid Extraction Kit (Aidlab Biotechnologies, Beijing, China) following the manufacturer’s guidelines. The RNA was then subjected to high-throughput sequencing of small RNA to detect any viruses using the Illumina Hiseq4000 platform at Biomarker Technologies (Beijing, China). Over 20 million clean reads between 18 and 35 nt were obtained. Using Velvet 1.0 software (Zerbino and Birney 2008), 6,942 contigs from 33 to 416 nt were assembled. Although the majority of the contigs were mapped to the host genome, 58, 13, and 10 contigs were mapped to AMV (Alfamovirus, Bromoviridae, reference sequences [RSs] AMV-RNA1 NC_001495, AMV-RNA2 NC_002024, and AMV-RNA3 NC_002025), alfalfa dwarf virus (ADV, Rhabdovirus, Rhabdoviridae, RS KP205452), and alfalfa leaf curl virus (ALCV, Capulavirus, Geminiviridae, RS KX574859), respectively. The 10 projected ALCV contigs totaled 1,113 nt, accounting for 40.47% of the complete ALCV RS of 2,750 nt. The nucleotide sequence identity between these contigs and the ALCV RS ranged from 96 to 100%. Total DNA was then extracted from the composite sample using a New Plant Genomic DNA Rapid Extraction Kit (Aidlab Biotechnologies) following the manufacturer’s guidelines. The presence of ALCV in the pooled sample was confirmed by PCR using an ALCV-specific primer pair, ALCV-1F 5′-TGGAATATTGTGCTGCTTGG-3′ and ALCV-1R 5′-ATTTTGGGACTTGTGCTCCA-3′ (Roumagnac et al. 2015), and subsequent cloning and Sanger sequencing. The 785-nt-long amplicon, deposited in GenBank as MK422439, exhibited a sequence identity of 96% to the ALCV RS. To further confirm the result, the full genome of ALCV in the pooled sample was amplified by fusion PCR using improved primer pair ALCV-F 5′-CCCTGGCCTGCTAAAGTGGCCCAATTCAACATGG-3′ and ALCV-R 5′-CCAGGGGGCCTTATTCCTCTGGGACCG-3′ adapted from Bernardo et al. (2016), cloned, and sequenced. The complete 2,750-bp sequence was deposited in GenBank as MK422438. BLASTn analysis indicated the sequence shared 90 and 98% identity with previously reported ALCV isolates from France (KT214370) (Roumagnac et al. 2015) and Argentina (MG792039) (Bejerman et al. 2018), respectively, thus confirming the ALCV identity of the virus. To reveal whether ALCV was associated with the symptoms, all samples were subjected to PCR with the primer pair ALCV-1F/ALCV-1R. ALCV was detected in 38 of 117 samples: in 8 of 26 samples with macular mosaic, 5 of 21 with mottle mosaic, 11 of 27 with shrinkage, 8 of 25 with mosaic shrinkage, and 6 of 17 with dwarfism, but not in the single plant showing etiolation. Interestingly, AMV was detected in the pooled sample as well as all 117 individual samples by RT-PCR, whereas ADV failed to be detected by RT-PCR in any of the samples. These results demonstrated that ALCV was present in alfalfa in China, and it often coinfected alfalfa plants with AMV. This is the first report of ALCV infecting alfalfa in China. The distribution of ALCV within alfalfa-growing regions, the identity of potential virus reservoirs, and the economic impact have yet to be determined. The results help expand understanding of this virus and help in selection of virus-free propagation material for resistant breeding of alfalfa and production of high-quality forage.

Herbage mass and chemical composition of the heterogeneous grasslands affected by harvesting time in Subtropical terrain Nepal

A study was carried out to evaluate the productivity and chemical composition of heterogeneous grasslands at Agriculture and Forestry University (AFU) livestock farm. The four grassland ecotypes were chosen as upland north, upland south, lowland south and lowland north. The dominating herbage species and cover abundance by the botanical groups were studied on day before the harvesting. Later, the herbage dry matter productivity was estimated by quadrat cutting during May and June, 2017. Chemical analysis was done by using the proximate method for dry matter (DM), crude protein (CP), crude fiber (CF) and ether extract (EE) content. Research results showed that the AFU grassland dominated by perennial grasses and sedges followed by the forbs. The mean coverage of grasses and sedges was about 55%, whilst that of forbs was about 29% and the least was for legumes (about 4%). The cumulative herbage mass was about 1.53 t/ ha on the DM basis, whilst the highest DM was found in the upland-south (1.74 t/ha) and the least was in the upland-north (1.334 t/ha). The proximate analysis further revealed that the site had no effect on CF content, whilst the CP was significant only at the second harvest for the lowland north (8.34%). Data revealed that the herbage composition might depend upon the soil moisture availability and geographical aspect. The dominance of perennial grasses at AFU grasslands revealed the yield stability, but needs the improvement through inoculation with leguminous forages for improved feed quality.