Leguminous Species Research Articles

Genome-wide identification of ascorbate-glutathione cycle gene families in soybean (Glycine max) reveals gene duplication events and specificity of gene members linked to development and stress conditions

Ascorbate-glutathione (AsA-GSH) cycle plays an important role in tuning beneficial ROS accumulation for intracellular signals and imparts plant tolerance to oxidative stress by detoxifying excess of ROS. Here, we present genome-wide identification of AsA-GSH cycle genes (APX, MDHAR, DHAR, and GR) in several leguminous species and expression analyses in G. max during stress, germination and tissue development. Our data revealed 24 genes in Glycine genus against the maximum of 15 in other leguminous species, which was due to 9 pars of duplicated genes mostly originated from sub/neofunctionalization. Cytosolic APX and MDHAR genes were highly expressed in different tissues and physiological conditions. Germination induced genes encoding AsA-GSH proteins from different cell compartments, whereas vegetative phase (leaves) stimulated predominantly genes related to chloroplast/mitochondria proteins. Moreover, cytosolic APX-1, 2, MDHAR-1a, 1b and GR genes were the primary genes linked to senescence and biotic stresses, while stAPX-a, b and GR (from organelles) were the most abiotic stress related genes. Biotic and abiotic stress tolerant genotypes generally showed increased MDHAR, DHAR and/or GR mRNA levels compared to susceptible genotypes. Overall, these data clarified evolutionary events in leguminous plants and point to the functional specificity of duplicated genes of the AsA-GSH cycle in G. max.

Host-specific influence on early growth and physiological attributes of sandal (Santalum album) grown in farmlands

Aim: The present study aimed to investigate the host- specific compatibility of sandal (Santalum album) for better root proliferation and boosting the growth of tree. Methodology: Sandal (Santalum album) was grown with 8 different leguminous and non-leguminous species at early stage to evaluate its biometric growth (height and basal diameter) and physiological (chlorophyll, photosynthesis rate and transpiration rate) performance under field conditions. Results: Sandal grown with Sesbania grandiflora recorded highest biometric observations, chlorophyll, photosynthesis and transpiration rate followed by Sandal + Albizia lebbeck and sandal + Casuarina junghuhniana. The sandal grown with leguminous host showed superior growth performance than sandal grown with non-leguminous host. Interpretation: The present study recommended that Sesbania grandiflora can be grown as transit host for boosting the growth of sandal.

Hydrodynamic attributes and potential hydrophobicity of a Typic Hapludult soil under secondary Atlantic forest, degraded pasture and leguminous trees, in Southeastern Brazil

Soil physical quality loss is mainly caused by compaction and soil structure deterioration. Both these processes influence water dynamic attributes such as hydraulic conductivity at saturation and sorptivity, as shown in field and laboratory studies with soil aggregates or soil samples preserved inside jackets. This study aimed: (i) to assess the link between different vegetation covers and physical attributes used to describe soil water dynamics and potential soil water repellency; and (ii) to identify whether these attributes recovered after 17-year revegetation with leguminous trees. The experimental area is located in Conceição de Macabú County, Rio de Janeiro State, Brazil. Soil aggregates were applied to tests with a miniaturized tension infiltrometer, allowing to obtain several soil hydrodynamic variables. For the surface horizon, soil hydrophobic behavior did not occur under pasture but occurred under tree covers, with the natural forest and sabiá sites being the highlights. For the subsurface horizon, the natural forest and sabiá sites were classified as non-hydrophobic and the pasture site as hydrophobic, as opposed to what was verified for the surface horizon. For both horizons, the soil under leguminous trees presented results close to those of the soil under forest, and very different from those of soil under pasture. Potential hydrophobicity levels justify the obtained opposite-to-expected hydrodynamic results, such as the lower conductivity and sorptivity occurring despite the lowest compaction and the higher conductivity and sorptivity occurring despite the highest compaction. Therefore, it was concluded that potential hydrophobicity levels affect hydrodynamic attributes and that revegetation using leguminous tree species leads to recovery of the natural soil conditions and perhaps their capacity to exert their original ecological functions.

Degradation of the Indospicine Toxin from Indigofera spicata by a Mixed Population of Rumen Bacteria.

The leguminous plant species, Indigofera linnaei and Indigofera spicata are distributed throughout the rangeland regions of Australia and the compound indospicine (L-2-amino-6-amidinohexanoic acid) found in these palatable forage plants acts as a hepatotoxin and can accumulate in the meat of ruminant livestock and wild camels. In this study, bovine rumen fluid was cultivated in an in vitro fermentation system provided with Indigofera spicata plant material and the ability of the resulting mixed microbial populations to degrade indospicine was determined using UPLC–MS/MS over a 14 day time period. The microbial populations of the fermentation system were determined using 16S rRNA gene amplicon sequencing and showed distinct, time-related changes occurring as the rumen-derived microbes adapted to the fermentation conditions and the nutritional substrates provided by the Indigofera plant material. Within eight days of commencement, indospicine was completely degraded by the microbes cultivated within the fermenter, forming the degradation products 2-aminopimelamic acid and 2-aminopimelic acid within a 24 h time period. The in vitro fermentation approach enabled the development of a specifically adapted, mixed microbial population which has the potential to be used as a rumen drench for reducing the toxic side-effects and toxin accumulation associated with ingestion of Indigofera plant material by grazing ruminant livestock.

Effect of Presowing Treatments on Seed and Seedling Quality Attributes of an Endemic Agroforestry Tree Acacia nilotica subsp. cupressiformis (J.L. Stewart) Ali and Faruqi

Background: Acacia nilotica var. cupressiformis is an evergreen multipurpose leguminous tree species which is suitable to agroforestry purposes and mainly distributed in Western parts of Rajasthan in India particularly Pali and its adjoining areas. The species has many advantages, however the natural germination in wild is very limited due to its hard seed coat dormancy. Methods: The experiment was conducted to study the effect of presowing treatment on seed coat of A. nilotica var. cupressiformis seeds with ten treatments in Completely Randomized Block Design at ICAR-Central Arid Zone Research Institute, Regional Research Station, Pali Marwar. The treatments were replicated thrice. Result: Among the treatments, maximum germination and higher values was obtained in sand paper scarification with water soaking for 12hrs (T2) followed by mechanical scarification with sand paper (T1), acid scarification (50% for 20 min) (T7) and acid scarification (98% for 10 min) (T5). Further, the present study aims to initiate the research areas for conservation and utilization of A. nilotica var. cupressiformis in Western parts of Rajasthan and other parts of India.

Vicilin from Anadenanthera colubrina Seeds: An alternative tool to combat Callosobruchus maculatus.

Vicilins are seed proteins, and they constitute 70-80% of the total protein in leguminous seeds; with amolecular mass between 150 and 190kDa, they are composed of subunits without disulfide bridges, with high affinity for chitin-binding. They are also associated with seed defense against insect pests. The chitin-binding vicilin from Anadenanthera colubrina seeds was purified by ammonium sulfate, followed by affinity chromatography on a chitin column, molecular exclusion on Superdex 75 Tricorn in FPLC system and Phenomenex C8 chromatography in HPLC system. The A. colubrina vicilin, named AcV, is a tetrameric glycoprotein composed of 1.55% carbohydrates and molecular weight determined by SDS-PAGE, consisting of 70, 73, 43 and 41kDa. The AcV homogeneity was confirmed in native PAGE, where it was observed to be a unique band with slow mobility in this gel, with approximately 230kDa. AcV added to the Callosobruchus maculatus diet in the bioassays resulted in a strong effect on adult emergence (ED50 of 0.096%), and in larvae caused a marked reduction in mass (WD50 of 0.32%) and lethality (LD50 of 0.33%) (w:w). The digestibility of AcV was evaluated in vitro with the digestive enzymes of larvae of C. maculatus of fourth instar, showing major fragments of 10 and 30kDa. AcV showed reactivity against the anti-EvV antibody from Erythrina velutina vicilin. The deleterious effects of AcV are likely to be associated with the chitin-binding fragments generated by proteolysis in the bruchid gut, similarly to that found for vicilins from other leguminous plant species, Enterolobium contortisiliquum and Vigna unguiculata. AcV might be a candidate protein for a possible bioinsecticidal control of the bruchid weevil, C. maculatus.

Fertilization and seasonality influence on the photochemical performance of tree legumes in forest plantation for area recovery in the Amazon.

N-fixing leguminous species can reach atmospheric dinitrogen gas (N2), having an advantage under N-limited degraded environments. These N-fixers are constantly used as facilitative species. Chlorophyll a fluorescence (ChF) acknowledges how different species take up and use light energy during photosynthesis. These techniques assess stress and performance responses to photosynthesis and are used for the selection of species with potential for reforestation. Six Fabaceae species were selected for this study: three nonfixing species (Cenostigma tocantinum, Senna reticulata and Dipteryx odorata) and three N-fixing species (Clitoria fairchildiana, Inga edulis and Acacia spp.). Variations in chlorophyll fluorescence under high vs. low water and nutrient conditions were studied. Multivariate analysis was performed to detect the effects of seasonality and fertilization on dark-adapted ChF two years after the experiment was established. The correlation among ChF variables and growth, photosynthesis and foliar nutrient concentrations was evaluated. Under high water- and nutrient-availability conditions, plants exhibited an enhanced performance index on absorption basis values correlated with electron transport fluxes. Under drought and nutrient-poor conditions, most species exhibit increased energy dissipation as photoprotection. High interspecific variation was found; therefore, species-specific responses should be considered in future ChF studies. Corroborating the ability to colonize high-light environments, N-fixers showed an increased performance index correlated with electron transport and Zn and N foliar concentrations. Negative correlations were found between photosynthesis and trapped fluxes. Diameter growth was positively correlated with electron transport fluxes. Given the different responses among species, ChF is an effective technique to screen for seasonality, fertilization and species effects and should be considered for use during forest restoration. Finally, the addition of fertilization treatments may facilitate tropical forest restoration due to the importance of nutrients in physiological processes. N-fixers showed high photochemical performance and tolerance to abiotic stress in degraded areas and therefore should be included to support ecosystem biomass restoration.

Comparative Transcriptome Analysis of Sophora japonica (L.) Roots Reveals Key Pathways and Genes in Response to PEG-Induced Drought Stress under Different Nitrogen Conditions

Sophora japonica is a native leguminous tree species in China. The high stress tolerance contributes to its long lifespan of thousands of years. The lack of genomic resources greatly limits genetic studies on the stress responses of S. japonica. In this study, RNA-seq was conducted for S. japonica roots grown under short-term 20% polyethylene glycol (PEG) 6000-induced drought stress under normal N and N starvation conditions (1 and 0 mM NH4NO3, respectively). In each of the libraries, we generated more than 25 million clean reads, which were then de novo assembled to 46,852 unigenes with an average length of 1310.49 bp. In the differential expression analyses, more differentially expressed genes (DEGs) were found under drought with N starvation than under single stresses. The number of transcripts identified under N starvation and drought in S. japonica was nearly the same, but more upregulated genes were induced by drought, while more downregulated genes were induced by N starvation. Genes involved in “phenylpropanoid biosynthesis” and “biosynthesis of amino acids” pathways were upregulated according to KEGG enrichment analyses, irrespective of the stress treatments. Additionally, upregulated N metabolism genes were enriched upon drought, and downregulated photosynthesis genes were enriched under N starvation. We found 4,372 and 5,430 drought-responsive DEGs under normal N and N starvation conditions, respectively. N starvation may aggravate drought by downregulating transcripts in the “carbon metabolism”, “ribosome”, “arginine biosynthesis pathway”, “oxidative phosphorylation” and “aminoacyl-tRNA biosynthesis” pathways. We identified 78 genes related to N uptake and assimilation, 38 of which exhibited differential expression under stress. A total of 395 DEGs were categorized as transcription factors, of which AR2/ERF-ERF, WRKY, NAC, MYB, bHLH, C3H and C2C2-Dof families played key roles in drought and N starvation stresses. The transcriptome data obtained, and the genes identified facilitate our understanding of the mechanisms of S. japonica responses to drought and N starvation stresses and provide a molecular foundation for understanding the mechanisms of its long lifespan for breeding resistant varieties for greening.

Cowpea Ecophysiological Responses to Accumulated Water Deficiency during the Reproductive Phase in Northeastern Pará, Brazil

Cowpea (Vigna unguiculata (L.) Walp.) is a leguminous species widely cultivated in northern and northeastern Brazil. In the state of Pará, this crop still has low productivity due to several factors, such as low soil fertility and climatic adversity, especially the water deficiency. Therefore, the present study aimed at evaluating the physiological parameters and the productivity of cowpea plants under different water depths. The experiment was conducted in Castanhal/Pará between 2015 and 2016. A randomized block design was applied with six replications and four treatments, represented by the replacement of 100%, 50%, 25% and 0% of the water lost during crop evapotranspiration (ETc), starting from the reproductive stage. The rates of net photosynthesis (A), stomatal conductance (gs), leaf transpiration (Eleaf), substomatal CO2 concentration (Ci), leaf temperature (Tleaf) and leaf water potential (Ψw) were determined in four measurements at the R5, R7, R8 and R9 phenological stages. Cowpea was sensitive to the water availability in the soil, showing a significant difference between treatments for physiological variables and productivity. Upon reaching a Ψw equal to −0.88 MPa, the studied variables showed important changes, which allows establishing this value as a threshold for the crop regarding water stress under such experimental conditions. The different water levels in the soil directly influenced productivity for both years, indicating that the proper water supply leads to better crop growth and development, increasing productivity.

Impact of Mycorrhization on Phosphorus Utilization Efficiency of Acacia gummifera and Retama monosperma under Salt Stress

The impact of salt stress on the growth and phosphorus utilization efficiency (PUE) of two leguminous species: Retama monosperma and Acacia gummifera was studied. The effectiveness of arbuscular mycorrhizal fungi (AMF) to mitigate salt stress was furthermore assessed. Growth, N and P tissue concentrations, mycorrhizal root colonization frequency and intensity, and P utilization efficiency (PUE) in the absence or presence of AMF were evaluated under no salt (0 mM L−1) and three salt (NaCl) concentrations of (25, 50 and 100 mM L−1) using a natural sterilized soil. A significant difference in mycorrhizal colonization intensity, root-to-shoot ratio, P uptake, PUE, and N uptake was observed between the legume species. Salt stress inhibited the shoot and root growth, and reduced P and N uptake by the legume species. Mycorrhizal inoculation aided to mitigate the effects of salt stress with an average increase of shoot and root growth responses by 35% and 32% in the inoculated than in the non-inoculated A. gummifera treatments. The average shoot and root growth responses were 37% and 45% higher in the inoculated compared to the non-inoculated treatments of R. monosperma. Average mycorrhizal shoot and root P uptake responses were 66% and 68% under A. gummifera, and 40% and 95% under R. monosperma, respectively. Mycorrhizal inoculated treatments consistently maintained lower PUE in the roots. The results provide insights for further investigations on the AMF conferred mechanisms to salt stress tolerance response by A. gummifera and R. monosperma, to enable the development of effective technologies for sustainable afforestation and reforestation programs in the Atlantic coast of Morocco.

Complete Genome Sequence of a Pseudomonas simiae Strain with Biocontrol Potential against Aphanomyces Root Rot.

Aphanomyces euteiches is a soilborne plant pathogen. It causes severe root rot in leguminous crop species. We report the complete genome sequence of a biocontrol strain, Pseudomonas simiae K-Hf-L9. The strain inhibited Aphanomyces euteiches mycelia and zoospores and suppressed root rot in field peas grown under controlled growth chamber conditions.

Could more efficient utilization of ecosystem services improve soil quality indicators to allow sustainable intensification of Amazonian family farming?

In the Amazonian periphery, there are sources of numerous disservices, including deforestation, loss of wildlife habitat and biodiversity erosion. However, there are great opportunities to adopt appropriate agricultural management practices to take advantage of the benefits of ecosystem services for sustainable agricultural intensification. Thus, the aim of this work was to evaluate the effects of certain ecosystem services provided by combined use of legumes with residue of low- and high-quality on soil quality indicators, nitrogen use efficiency and sustainability of maize grain yield in infertile tropical soil. The overarching objective is to determine how ecosystem services can contribute to the improvement of land-use policy to ensure the sustainability of cultivated lands, in such a way that forest can be preserved by avoiding deforestation of other new areas through shifting cultivation systems. Four leguminous tree species were used, two with high-quality residues Leucaena leucocephala (leucaena) and Gliricidia sepium (gliricidia) and two with low-quality residues Clitoria fairchildiana (clitoria) and Acacia mangium (acacia). Maize grain yield was evaluated between 2011 and 2017 in these treatments. In 2018, to assess how ecosystem services affect crop performance, the treatmentswere divided into ten treatments with and without urea.We conclude that increased uptake of inorganic and organic N by maize resulting from improvement of the soil quality indicators may allow agricultural intensification. This improvement can help meet the challenges of sustainability and feasibility of agroecosystems of the Amazonian periphery by making the agroecosystem more productive year by year. Therefore, our results confirm that the utilization of an ecosystem services style approach can help meet the challenges of sustainability and feasibility in agrosystems of the Amazonian periphery. In addition, these results can contribute to the development of land-use policy in the Amazonian periphery, aiming for the intensification of agriculture in cropped areas to avoid deforestation of new areas from shifting cultivation systems.

Soil carbon sequestration by agroforestry systems in China: A meta-analysis

China has a rich historical heritage of agroforestry, but a quantitative analysis of the potential of agroforestry systems (AFS) for soil organic carbon (SOC) sequestration is missing. A comprehensive meta-analysis of soil C sequestration rates derived from 43 studies was undertaken to determine its most influential parameters. Soil C sequestration rates were calculated for topsoils (0–20 cm, 97 sites) and at two subsoil layers (20–40 cm, 73 sites; 40–60 cm, 54 sites). The results showed highest C sequestration rates for the AFS-type shelterbelt in topsoils (0.92 Mg ha−1 yr−1), upper subsoils (0.72 Mg ha−1 yr−1) and lower subsoils (0.52 Mg ha−1 yr−1), followed by agrosilvicultural systems (0.70, 0.48 and 0.43 Mg ha−1 yr−1, respectively) and silvopastoral systems (0.23, 0.08 and 0.02 Mg ha−1 yr−1, respectively). We tested potential effects of different predictor variables (soil class, AFS-type, land use of the control site, system age, initial SOC stock, tree components, legumes and climatic properties) on soil C sequestration rates using a Random Forest regression model. We found changes in the conditional importance of the predictors for different soil layers. For both top- and subsoils, the AFS-type, initial SOC and soil class were most influential, followed by age. Other factors such as land use of the control, climate factors (climate zone, mean annual temperature, mean annual precipitation), leguminous species and tree components were of minor importance. We conclude that besides the AFS-type and the initial SOC, soil type plays a decisive role for the efficiency of soil C sequestration by agroforestry. Our meta-analysis provided evidence that existing AFS in China, particularly shelterbelts and agrosilvicultural systems, are effective practices to increase SOC stocks, both in top- and subsoils and especially in the subtropical climate zone.

Neighbors, Drought, and Nitrogen Application Affect the Root Morphological Plasticity of Dalbergia odorifera.

In forest systems, neighbor-induced root morphological plasticity (RMP) is species specific and environment dependent. However, related studies on leguminous woody trees remain sparse. The objectives of this study were to evaluate the root morphological response of the leguminous woody Dalbergia odorifera T. Chen to different N-fixing niche neighbors under models of root system contact and isolation and to evaluate whether such response can be modified by drought or the application of nitrogen (N). The relationship between root morphology and the relative competitiveness of the whole D. odorifera plantlet was also assessed. D. odorifera plantlets from the woody Leguminosae family were used as target species and were grown with either identical N-fixing niche D. odorifera, the heterogeneous but con-leguminous Delonix regia, or the non-leguminous Swietenia mahagoni. All plants were grown under two water conditions (100% and 30% field capacity) and two N treatments (no N application and N application). Two planting models (root system contact in Experiment 1, root system isolation in Experiment 2) were applied to neighboring plantlets. The RMP of D. odorifera was assessed based on root morphology, root system classification, root nodules, and RMP-related indices. The growth of D. odorifera was estimated based on the relative growth ratio, net assimilation rate, and leaf N content. The relative competitiveness of the whole D. odorifera plantlet was evaluated through relative yield. The results of Experiment 1 showed that D. odorifera had different RMP responses to a different N-fixing niche neighbor with root system contact. The RMP of D. odorifera was promoted by a different N-fixing niche neighbor under conditions of drought or N deficiency. Drought improved the RMP of D. odorifera exposed to a different N-fixing niche neighbor. N application converted the promoting effect of D. regia on RMP to an inhibitory effect under well-watered conditions. Experiment 2 showed that belowground interaction with a different N-fixing niche neighbor may be the only way to influence RMP, as effects of aboveground interaction were negligible. Finally, correlation analysis showed that neighbor-induced RMP might predict the relative competitiveness of the whole D. odorifera plantlet under conditions of drought or N deficiency. These findings highlight the influences of neighbors, drought, and N application on the RMP of D. odorifera and contribute to understanding neighbor-induced dynamic changes in the root traits of leguminous woody species in forest systems in the context of climate change.

ANALYSIS OF THE CHEMICAL ATTRIBUTES OF A TYPIC HAPLUDULT SOIL UNDER FOREST SYSTEMS

The aim of this study was to evaluate the chemical quality of a Typic Hapludult soil under secondary forest (capoeira), pasture and three leguminous tree species: Acacia auriculiformis, Mimosa caesalpiniaefolia and Inga edulis, in Conceição de Macabú County, Rio de Janeiro State, Brazil, implemented in December 1998. Soil samples from the 0-0.10 and 0.10-0.20 m layers were collected and analyzed in July/2015. The C content in the 0.10 m layer was higher in capoeira and lower in the pasture. The CECef and CECpH=7 values and the N, P, Ca, Mg and K levels were lower in pasture, higher in Acacia auriculiformis or capoeira, and intermediate in Inga edulis and Mimosa caesalpiniaefolia. The chemical variables regarding the vegetation cover generally had the lowest values in the pasture, the highest in the Acacia auriculiformis or capoeira, and intermediate values in Inga edulis and Mimosa caesalpiniaefolia. It was concluded that revegetation leads to changes in the superficial layer of the soil which make its attributes closer to those of capoeira and further away from those of pasture, indicating an increase in quality to support the functioning of a forest ecosystem, despite the worsening of some Agronomic quality indicators.

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.

Sustainable effect of a symbiotic nitrogen-fixing bacterium Sinorhizobium meliloti on nodulation and photosynthetic traits of four leguminous plants under low moisture stress environment.

Sustainable effect of a nitrogen-fixing bacterium Sinorhizobium meliloti on nodulation and photosynthetic traits (phenomenological fluxes) in four leguminous plants species under low moisture stress (20-25% soil moisture content) environment was studied. Sinorhizobium meliloti was isolated from fenugreek (Trigonella foenum-graecum) root nodules, and later, it was cultured and purified. Nodulation and photosynthetic ability in the presence of S. meliloti were tested in four leguminous plant species, that is, kidney bean (cv. lobia-2000), black bean (cv. NM-97), mung bean (cv. NM-2006) and chickpea (cv. Pb-2008). Plants of each species were grown in sterilized soil that was previously treated with 25ml suspension containing S. meliloti at 41×106 CFUml-1 kg-1 pot. One-month-old plants were subjected to low soil moisture stress conditions for 15days, and soil moisture contents were maintained to 20-25% throughout the experimental period. The ability to fix nitrogen, nodule formation, and their subsequent effect on phenomenological fluxes in low moisture treated legumes were studied.

Growth and competition between a native leguminous forb and an alien grass from the Cerrado under elevated CO2

AbstractThe increase in atmospheric CO2 concentration ([CO2]) due to climate change may alter the composition of communities and the functioning of ecosystems. Owing to greater nitrogen use efficiency, leguminous plants present more effective responses to increasing [CO2] than non‐legumes. The objective of this study was to evaluate the morphophysiological and growth responses of two species from the Cerrado, a native C3 herbaceous legume (Stylosanthes capitata Vogel.) and an invasive C4 grass (Melinis minutiflora P. Beauv) growing alone or in competition, in ambient (350 ppm) and high (1000 ppm) [CO2]. Competition with S. capitata reduced leaf development and dry matter production in M. minutiflora individuals, regardless of [CO2]. Stylosanthes capitata increased root system growth under high [CO2] and competition. This change allows greater soil exploitation, decreasing nutrient limitation to S. capitata development. The leguminous species S. capitata showed advantages in the competition for resources under high [CO2] concerning the invasive grass. Although invasive C4 species are initially better in the colonisation of the invaded areas, the C3 native species of Cerrado may adjust morphophysiological traits when growing at high [CO2] and develop strategies that enable it to more effectively compete for resources.

Cover crops in the inter-row of a table grape vineyard managed with irrigation sensors: Effects on yield, quality and glutamine synthetase activity in leaves

Researchers, farmers and viticulturists have focused on the development and adoption of alternative management strategies that are more environmentally and economically sustainable. One strategy could be cover crops, which are often sowed as a mix of non-leguminous and leguminous species, with positive effects on nitrogen nutrition of the vines . Irrigation of cover cropped vineyards can be managed with the use of wireless soil sensors. Nitrogen (N) is the most important soil mineral nutrient for plant growth and glutamine synthetase (GS) is not only responsible for N assimilation, but is also involved in different responses to both biotic or abiotic stresses. Therefore, the aims of this this study were to determine the effects of two different soil management practices (cover crops and tillage) on the vegetative activity of Italia table grape, as well as on fruit yield and quality and on the GS enzyme activity at different phenological stages of the grapevine. White clover reduced the canopy of Italia vines but increased the GS activity; no effects were reported for yield and quality of harvested clusters.

Evaluating the genetic diversity in two tropical leguminous trees, Dalbergia cochinchinensis and D. nigrescens, in lowland forests in Cambodia and Thailand using MIG-seq.

It is vital to measure the levels of genetic diversity and differentiation between populations in a species to understand the current genetic structure and evolution of the species. Here, MIG-seq (multiplexed inter-simple sequence repeat genotyping by sequencing) was employed to assess the genetic variation in two tropical leguminous tree species, Dalbergia cochinchinensis and D. nigrescens, in Cambodia and Thailand. Sequence data for 255-618 loci, each with an approximate length of 100 bp, were obtained, and the nucleotide diversity, Tajima's D and FST were computed. The estimates calculated from the data obtained by MIG-seq were compared to those obtained by Sanger sequencing of nine nuclear coding genes in D. cochinchinensis in our previous study. The nucleotide diversity at the MIG-seq loci was slightly higher than that at silent sites in the coding loci, whereas the FST values at the MIG-seq loci were generally lower than those at the coding loci, although the differences were not significant. Moreover, nucleotide diversities within populations of the two species were similar to each other, at approximately 0.005. Three and four population clusters were genetically recognized in D. cochinchinensis and D. nigrescens, respectively. Although the populations were differentiated from each other, the levels of differentiation among them, as measured by FST, were higher in D. cochinchinensis than in D. nigrescens. This indicates higher levels of gene flow between the populations in the latter species. We recommend using MIG-seq for quick surveys of genetic variation because it is cost-effective and results in smaller variance in the estimates of population genetic parameters.