Exploration of the Diversity of Vicine and Convicine Derivatives in Faba Bean (Vicia faba L.) Cultivars: Insights from LC-MS/MS Spectra

While numerous Fabaceae seeds are a good nutritional source of high-quality protein, the use of some species is hampered by toxic effects caused by exposure to metabolites that accumulate in the seeds. One such species is the faba or broad bean (Vicia faba L.), which accumulates vicine and convicine. These two glycoalkaloids cause favism, the breakdown of red blood cells in persons with a glucose-6-phosphate dehydrogenase deficiency. Because this is the most common enzyme deficiency worldwide, faba bean breeding efforts have focused on developing cultivars with low levels of these alkaloids. Consequently, quantification methods have been developed; however, they quantify vicine and convicine only and not the derivatives of these compounds that potentially generate the same bio-active molecules. Based on the recognition of previously unknown (con)vicine-containing compounds, we screened the fragmentation spectra of LC-MS/MS data from five faba bean cultivars using the characteristic fragments generated by (con)vicine. This resulted in the recognition of more than a hundred derivatives, of which 89 were tentatively identified. (Con)vicine was mainly derivatized through the addition of sugars, hydroxycinnamic acids, and dicarboxylic acids, with a group of compounds composed of two (con)vicine residues linked by dicarboxyl fatty acids. In general, the abundance profiles of the different derivatives in the five cultivars mimicked that of vicine and convicine, but some showed a derivative-specific profile. The description of the (con)vicine diversity will impact the interpretation of future studies on the biosynthesis of (con)vicine, and the content in potentially bio-active alkaloids in faba beans may be higher than that represented by the quantification of vicine and convicine alone.

Pierid Butterflies, Legume Hostplants, and Parasitoids in Urban Areas of Southern Florida

Are parasitoids less likely to find their Lepidoptera hosts on non-native hostplants than native hostplants? We predicted that with longer periods of coevolution between herbivores and the plants they consume, the parasitoids that provide top-down control would be more attuned to finding their hosts on native plants. To test this hypothesis, we collected immature stages of sulfur butterflies (the cloudless sulfur (Phoebis sennae) and the orange-barred sulfur (Phoebis agarithe) over a three-year period (2008-2011) from native and ornamental hostplants in the genus Senna in three different parts of the urban landscape of Miami, Florida, USA. We reared the immature specimens to pupation and either eclosion of adults or emergence of parasitoids and compared the levels of parasitization among the three areas, and among native vs. exotic hostplants. We found, contrary to our prediction, that caterpillars feeding on non-native leguminous hostplant species were more likely to be parasitized than those feeding on native hostplants. We discuss this surprising finding in the light of recent findings in other plant/herbivore/parasitoid systems.

Adesmia pinifolia, a Native High-Andean Species, as a Potential Candidate for Phytoremediation of Cd and Hg

This study highlights Adesmia pinifolia, a native high-Andean species, as a potential candidate for the phytoremediation of soils contaminated with Cd and Hg. In this work, a semi-hydronic assay with different doses of Cd (3, 4.5, and 6 mg L-1) and Hg (0.8, 1.2, and 1.6 mg L-1) was analysed to evaluate the establishment of plants, antioxidant defence systems, oxidative stress, and the ability to accumulate heavy metals. The results indicate high survival rates (>80%); however, Cd significantly reduced shoot and root biomass, while Hg increased root biomass with the 1.6 mg L-1 treatment. Cd and Hg tend to accumulate more in roots (2534.24 µg/g and 596.4 µg g-1, respectively) compared to shoots (398.53 µg g-1 and 140.8 µg g-1, respectively). A significant decrease in the bioconcentration factor of Cd and Hg in roots was observed as metal levels increased, reaching the maximum value at 3 mg L-1 (805.59 ± 54.38) and 0.8 mg L-1 (804.54 ± 38.09). The translocation factor, <1 for both metals, suggests that translocation from roots to shoots is limited. An overproduction of reactive oxygen species (ROS) was observed, causing lipid peroxidation and oxidative damage to plant membranes. Tolerance strategies against subsequent toxicity indicate that enhanced glutathione reductase (GR) activity and glutathione (GSH) accumulation modulate Cd and Hg accumulation, toxicity, and tolerance.

Undescribed matrine-type alkaloids from Sophora alopecuroides with anti-inflammatory activity

A phytochemical investigation on the alkaloid fractions of Sophora alopecuroides L. led to the production of 11 undescribed matrine-type alkaloids, sophaloseedlines I-S (1-11), 12 known analogs (12-23), and an unexpected artificial matrine-derived Al(III) complex (24). The corresponding structures were elucidated by the interpretation of spectroscopic analyses, quantum chemical calculation, and six instances (1-4, 18, and 24), verified by X-ray crystallography. The biological activities screening demonstrated that none of the isolates exhibited cytotoxicity against four human cancer cell lines (HepG2, A549, THP-1, and MCF-7) and respiratory syncytial virus (RSV) at 50 μM, while moderate anti-inflammatory activity with IC50 value from 15.6 to 47.8 μM was observed. The key structure-activity relationships of those matrine-type alkaloids for anti-inflammatory effects have been summarized. In addition, the most potent 7-epi-sophoramine (19) and aluminum sophaloseedline T (24) could effectively inhibit the release of pro-inflammatory factors (TNF-α, IL-6, and IL-1β), as well as the expression of iNOS and COX-2 proteins.

Unveiling foliar secreting sites and secretion composition in the legume tree Swartzia flaemingii Raddi

Secretory structures in plants play a crucial role in producing bioactive compounds. Despite the potential of the Swartzia genus, comprehensive studies in this context are still scarce. Swartzia is a legume tree (Fabaceae) that occurs in the Brazilian Atlantic Forest, a biodiversity hotspot, and includes species such as Swartzia flaemingii. Therefore, we aim to achieve: (1) identify and characterize the key secretory sites responsible for saponin production in S. flaemingii leaflets; (2) confirm the presence of saponins in S. flaemingii leaves by comparing them with known chemical profiles of other Swartzia species; (3) assess the potential hemolytic and cytotoxic effects of crude leaf extracts. Our investigation unveils the presence of phenolic idioblasts, mucilage cells, and articulate laticifers, which play pivotal roles in defense and adaptation. Notably, we report the first-ever ultrastructural details of laticifers in a legume species. Additionally, oleanane-type saponins were identified in the leaves, giving insights into the chemotaxonomic profile of Swartzia. The crude extracts show low cytotoxicity levels, showcasing as a promising alternative source of saponins. This investigation reinforces the importance of conserving plants in threatened regions like the Atlantic Forest, a global biodiversity hotspot facing substantial anthropogenic pressures.

Erythrina velutina Willd.: A review of its traditional uses, phytochemistry, pharmacology, and toxicology

ETHNOPHARMACOLOGICAL RELEVANCE

Erythrina velutina Willd., commonly known as "mulungu" in Brazil, is a leguminous tree with various traditional medicinal uses. These uses include treating insomnia, central nervous system disorders, convulsions, nervous cough, and inflammation.

AIM OF THE REVIEW

This review aims to comprehensively summarize the ethnomedicinal uses, chemical constituents, pharmacology, and toxicology of E. velutina to explore its potential as a source for new therapeutic agents.

MATERIALS AND METHODS

Information was collected from scientific databases, dissertations, and books. Chemical structures were generated using ChemDraw. To ensure the accuracy of the plant names, "World Flora Online" (www.worldfloraonline.org) was consulted for the accepted names of plants.

RESULTS

E. velutina is indigenous to Brazil, Peru, Ecuador, Colombia, Venezuela, and Hispaniola. Approximately 244 compounds, mainly alkaloids and flavonoids, have been isolated from it. The plant and its extracts have exhibited various bioactivities, such as anti-inflammatory, anxiolytic, anticonvulsant, neuroprotective, analgesic, antimicrobial, and antioxidant effects, validating some of its traditional medicinal uses. Erythrina velutina shows promising therapeutic potential for conditions like convulsion, central nervous disorders, anxiety, insomnia, and inflammation, primarily due to its alkaloid and flavonoid content.

CONCLUSION

The traditional medicinal uses of the plant, combined with modern scientific research, underscore its pharmacological potential. This makes it a significant candidate for drug development. Further research should focus on conducting toxicological studies, clinical trials, and mechanistic investigations. These efforts will enable a comprehensive exploration of its pharmacological properties and potential applications in drug development.

Genome-wide identification, characterization, and expression analysis of MIPS family genes in legume species

BACKGROUND

Evolutionarily conserved in plants, the enzyme D-myo-inositol-3-phosphate synthase (MIPS; EC 5.5.1.4) regulates the initial, rate-limiting reaction in the phytic acid biosynthetic pathway. They are reported to be transcriptional regulators involved in various physiological functions in the plants, growth, and biotic/abiotic stress responses. Even though the genomes of most legumes are fully sequenced and available, an all-inclusive study of the MIPS family members in legumes is still ongoing.

RESULTS

We found 24 MIPS genes in ten legumes: Arachis hypogea, Cicer arietinum, Cajanus cajan, Glycine max, Lablab purpureus, Medicago truncatula, Pisum sativum, Phaseolus vulgaris, Trifolium pratense and Vigna unguiculata. The total number of MIPS genes found in each species ranged from two to three. The MIPS genes were classified into five clades based on their evolutionary relationships with Arabidopsis genes. The structural patterns of intron/exon and the protein motifs that were conserved in each gene were highly group-specific. In legumes, MIPS genes were inconsistently distributed across their genomes. A comparison of genomes and gene sequences showed that this family was subjected to purifying selection and the gene expansion in MIPS family in legumes was mainly caused by segmental duplication. Through quantitative PCR, expression patterns of MIPS in response to various abiotic stresses, in the vegetative tissues of various legumes were studied. Expression pattern shows that MIPS genes control the development and differentiation of various organs, and have significant responses to salinity and drought stress.

CONCLUSION

The MIPS genes in the genomes of legumes have been identified, characterized and their expression was analysed. The findings pave way for understanding their molecular functions and evolution, and lead to identify the putative MIPS genes associated with different cell and tissue development.

Placoisoflavones A and B, two new cytotoxic isoflavonoids from Placolobium vietnamense N.D.Khôi & Yakovlev

Two previously unreported isoflavonoids, placoisoflavones A and B (1 and 2), along with five known compounds, calopogonium isoflavone B (3), jamaicin (4), 6-methoxycalopogonium isoflavone A (5), vestitol (6), and caviunin (7) have been isolated from the stems of Placolobium vietnamense N.D.Khôi & Yakovlev. The structures of all isolated compounds were fully characterized using spectroscopic data and comparison with the previous literature. The cytotoxicity of all isolated compounds was evaluated against HepG2 cell line, and compound 1 showed the most potent cytotoxicity with an IC50 value of 8.0 μM.

Insights from the yield, protein production, and detailed alkaloid composition of white (Lupinus albus), narrow-leafed (Lupinus angustifolius), and yellow (Lupinus luteus) lupin cultivars in the Mediterranean region

Introduction

Lupins and other legumes have been considered as alternative plant-based protein sources to soybeans for both humans and livestock. Furthermore, they can contribute to more sustainable agricultural systems. The productivity and chemical composition of legumes is highly variable between species, cultivars, and with the edaphoclimatic conditions.

Methods

This work evaluated the adaptability of seven Lupinus cultivars in two different sowing locations, during two consecutive years, through the characterization of their seed, as a means of investigating their suitability to be used as a source of food and/or feed.

Results and discussion

Lupinus angustifolius cv. Tango and Lupinus luteus cv. Acos were the most stable genotypes across the environments when considering the seed and protein production, while L. luteus cv. Alburquerque and L. luteus cv. Mister showed less variation in the total alkaloid content across the environments. The edaphoclimatic conditions affected seed and protein yields, as higher rainfall resulted in high productivity. The lower temperatures observed in the first year at both locations caused a reduction in the production of alkaloids in L. luteus cv. Acos and Cardiga. Due to the high alkaloid content of some of the studied cultivars their use as food or feed can pose some safety concerns. However, these cultivars can have high levels of resistance to herbivore and insect attacks, which can be of the utmost importance for the use of these crops for recovering poor or exhausted soils.

Antinociceptive and anti-inflammatory activities of essential oil of the leaves of Amburana cearensis (Allemão) A.C. Smith. from the semi-arid region of Northeastern Brazil

ETHNOPHARMACOLOGICAL RELEVANCE

Amburana cearensis (Allemão) A.C. Smith is a medicinal plant with wide distribution in South America, popularly known in Brazil as "cumaru" or "amburana de cheiro". In folk medicine, in the semi-arid region of Northeastern Brazil, infusions, teas and decoctions of leaves of Amburana cearensis have their practical use for treating fever, gastrointestinal disorders, inflammation, and inflammation pain. However, none of the ethnopharmacological properties has been scientifically evaluated using volatile compounds obtained from its leaves (essential oil).

AIM OF THE STUDY

This study investigated the chemical composition, acute oral toxicity, and antinociceptive and anti-inflammatory activities of the essential oil from the leaves of A. cearensis.

MATERIAL AND METHODS

The acute toxicity of the essential oil was investigated in mice. The antinociceptive effect was evaluated using the formalin test and, abdominal writhing induced by acetic acid, being investigated the possible mechanisms of action involved in antinociception. The acute anti-inflammatory effect was investigated through models of carrageenan-induced peritonitis, yeast-induced pyrexia, and carrageenan- and histamine-induced paw inflammation.

RESULTS

No acute toxicity was observed at doses up to 2000 mg/kg; p.o. The antinociceptive effect was statistically equal to morphine. In the formalin assay, the oil showed analgesic activity in the neurogenic and inflammatory phases, having as mechanisms the cholinergic, adenosinergic system, and ATP-sensitive potassium channels (K-ATP). In peritonitis, a reduction in TNF-α and IL-1β levels and leukocyte migration were observed. The antipyretic effect was statistically superior to dipyrone. The reduction in paw edema was statistically superior to the standard in both models.

CONCLUSION

The results obtained not only support the traditional use of the species in inflammatory conditions and pain in folk medicine but also demonstrate that this is a rich source of phytocomponents such as germacrone, which can be used as a natural and sustainable therapeutic agent with industrial applications.

Competition-induced downregulation of symbiotic nitrogen fixation

Controlled experiments at the level of individual plants show that legume species use different strategies for the regulation of symbiotic dinitrogen fixation in response to nitrogen availability. These strategies were suggested to improve legume fitness in the context of the plant community, although rarely studied at this level. We evaluated how nitrogen availability and conspecific vs heterospecific interactions influenced the strategy of regulation of nitrogen fixation. We grew two species of herbaceous legumes representing two different strategies of regulation without interaction, under treatments of deficient and sufficient nitrogen availability, with conspecific or heterospecific interaction. We found that Hymenocarpus circinnatus maintained a facultative strategy of downregulating nitrogen fixation when nitrogen was available under both con- and heterospecific interactions, as was also found for this species when grown alone. Vicia palaestina also downregulated nitrogen fixation under both con- and heterospecific interactions but did not regulate fixation when grown alone. Our results showed that under nitrogen limitation, interaction with a neighboring plant reduced fitness, reflecting a competitive effect. Our findings suggest that when interacting with other plants, downregulation of nitrogen fixation is more likely, therefore reducing the energetic cost of fixation, and improving plant performance in competitive ecological communities, especially when nitrogen is available.

Antidermatophytic quinolizidine alkaloids from Calpurnia aurea subsp. aurea (Aiton) Benth

From the leaves and stem bark of the Kenyan medicinal plant Calpurnia aurea subsp. aurea, four previously undescribed quinolizidine alkaloids namely, 2β-methoxy-13α-O-(2'-pyrrolylcarbonyl) virgiline, 2α-methoxy-13β-O-(2'-pyrrolylcarbonyl) virgiline, 3α-O-angelate-2β-hydroxy-13α-O-(2'-pyrrolylcarbonyl) virgiline, 2,3-dehydro-virgiline were isolated together with four known ones. Structural elucidation of the compounds was based on 1D and 2D NMR spectroscopy and mass spectrometry. Their relative configurations were determined by NOESY correlations and literature. The quinolizidine alkaloids were tested against Trichophyton rubrum, Trichophyton interdigitale, Trichophyton benhamiae, Microsporum canis and Nannizzia gypsea, common causative agents of most of the tinea infections in human. All the isolated quinolizidine alkaloids exhibited antidermatophytic activity with MIC ranging from 37.5 μg/ml to 300 μg/ml.

Vicia faba SV channel VfTPC1 is a hyperexcitable variant of plant vacuole Two Pore Channels

To fire action-potential-like electrical signals, the vacuole membrane requires the two-pore channel TPC1, formerly called SV channel. The TPC1/SV channel functions as a depolarization-stimulated, non-selective cation channel that is inhibited by luminal Ca2+. In our search for species-dependent functional TPC1 channel variants with different luminal Ca2+ sensitivity, we found in total three acidic residues present in Ca2+ sensor sites 2 and 3 of the Ca2+-sensitive AtTPC1 channel from Arabidopsis thaliana that were neutral in its Vicia faba ortholog and also in those of many other Fabaceae. When expressed in the Arabidopsis AtTPC1-loss-of-function background, wild-type VfTPC1 was hypersensitive to vacuole depolarization and only weakly sensitive to blocking luminal Ca2+. When AtTPC1 was mutated for these VfTPC1-homologous polymorphic residues, two neutral substitutions in Ca2+ sensor site 3 alone were already sufficient for the Arabidopsis At-VfTPC1 channel mutant to gain VfTPC1-like voltage and luminal Ca2+ sensitivity that together rendered vacuoles hyperexcitable. Thus, natural TPC1 channel variants exist in plant families which may fine-tune vacuole excitability and adapt it to environmental settings of the particular ecological niche.

A new acylated flavonol triglycoside and evaluation of the antioxidant activity of Astragalus armatus subsp. numidicus (Murb.) Emb. & Maire

A new acylated flavonol triglycoside, quercetin-3-O-(5'-p-hydroxybenzoyl)-β-D-apiofuranosyl-(1→2)[α-L-rhamnopyranosyl-(1→6)]-β-D-galactopyranoside (1), was isolated from the aerial parts of Astragalus armatus subsp. numidicus (Murb.) Emb. & Maire as well as ten known compounds, one phenolic compound, one flavonol-aglycone and eight flavonol-glycosides distributed into two monoglycosides, three diglycosides and three triosides. Their structures were mainly determined by 1D- and 2D-NMR experiments (1H,13C, COSY, HSQC, HMBC). The chloroform, ethyl acetate, n-butanol and hydroethanol extracts were tested for their antioxidant activity using five methods (DPPH, ABTS, Reducing power, CUPRAC and Phenanthroline). The ethyl acetate extract was the most active in CUPRAC (A0.5: 50.28 ± 2.16 µg/mL), ABTS (IC50: 49.73 ± 1.55 µg/mL) and Reducing power (A0.5: 58.13 ± 4.35 µg/mL) assays, whereas the hydroethanol and n-BuOH exhibited the highest activity in the Phenanthroline assay (A0.5: 9.93 ± 0.16) and (A0.5: 10.27 ± 0.44 µg/mL), respectively.

Cytotoxic effect and induction of apoptosis in human cervical cancer cells by a wood extract from Prosopis laevigata

Cervical cancer ranks fourth in incidence among women worldwide. Cisplatin is currently the first-line drug of treatment for cervical cancer; however, it causes serious adverse effects. Therefore, it is crucial to explore natural products for cervical cancer treatment. Prosopis laevigata is a medicinal plant frequently used for ophthalmological and gastrointestinal infections. In this study, we used the MTT cell viability assay to evaluate the cytotoxic effect of a wood extract from Prosopis laevigata (Extract T7) in SiHa, HeLa, Ca Ski, and C-33 A cancer cell lines. Phosphatidylserine translocation and cell cycle evaluations were performed to determine the mechanism of cellular death. The extract's safety was evaluated using the Ames test with Salmonella typhimurium strains, in vivo acute toxicity assay, and repeated dose toxicity assay in mice. We also identified phenolic compounds of Extract T7 through liquid chromatography/mass spectrometry. Naringin, catechin, and eriodictyol demonstrated a higher concentration in Extract T7. Additionally, Extract T7 exhibited a cytotoxic effect against cervical cancer cells, where C-33 A was the most sensitive (IC50= 22.58 ± 1.10 µg/mL and 14.26 ± 1.11 µg/mL at 24 h and 48 h respectively). Extract T7 induced death by apoptosis and cell cycle arrest in the G2 phase in C-33 A. Extract T7 was not mutagenic. No toxicological effects were observed during acute toxicity and repeated dose toxicity for 28 days. Therefore, further evaluations of Extract T7 should be conducted to identify the complete mechanism of action for potential anti-tumoral activity and safety before conducting studies in animal models.

Phylogenomic and morphological data reveal hidden patterns of diversity in the national tree of Brazil, Paubrasilia echinata

PREMISE

Paubrasilia echinata (common names, pau brasil, brazilwood) is the national tree of Brazil and an endangered species endemic to the Brazilian Atlantic Forest. Over its wide distribution of 2000 km, its leaflets morphology exhibits extensive plasticity. Three morphotypes are commonly identified based on leaf size, but it is unclear if they represent distinct taxa or a single polymorphic species. This study aims to clarify the taxonomic position of the three morphotypes to inform conservation decisions.

METHODS

A morphometric study of leaf characters of herbarium specimens was coupled with genetic analyses using genotype-by-sequencing data. We used maximum-likelihood and coalescent methods to evaluate the phylogenetic and population structure of the species. We compared these with a morphological dendrogram built from hierarchical clustering.

RESULTS

Two of the three morphotypes formed separately evolving lineages, the third morphotype formed two geographically separate lineages, and northern trees with intermediate leaf morphology formed a separate fifth lineage. Leaflet size varied by over 35-fold, and although morphological clustering generally matched the genetic patterns, there were some overlaps, highlighting the cryptic diversity within this group.

CONCLUSIONS

Our genetic and morphological results provide some evidence that cultivated trees from different states in Brazil seem to have a limited genetic origin and do not reflect the broader genetic and geographical diversity of the species. As a result, more care is likely needed to preserve the overall genomic diversity of this endangered and iconic species.

Gastroprotective evaluation of Medicago sativa L. (Fabaceae) on diabetic rats

Traditional uses for the plant Medicago sativa (M. sativa) (Alfalfa) (Family: Fabaceae) include liver protection, antioxidant activity, and the treatment of bleeding and digestive issues. This study aims to assess the effect of ethanol extract of M. sativa (EEMS) on experimental-induced ulcers in diabetic rats. By pylorus ligation and ethanol administration, gastric ulcers were induced in diabetic rats. Five groups each consisting of six rats in each model were used. All other groups except Group I were made diabetic by giving rats alloxan (140 mg/kg i.p.). Vehicles were given to Group I (normal control) and Group II (diabetes control) rats. Group III (positive control) received ranitidine 50 mg/kg, and Group IV and V received EEMS at doses of 100 and 400 mg/kg, respectively. In the pylorus ligation and ethanol-induced stomach ulcer model of rats, the findings demonstrated that EEMS (100 mg/kg) showed a decreased ulcer index of 2.01 ± 0.41 and was found statistically significant against the diabetes control group (p < 0.001) as well as, an ulcer index of 0.68 ± 0.22 by EEMS (400 mg/kg) with a significant reduction in the ulcer index (p < 0.001). EEMS (100 and 400 mg/kg) reduce free acidity by 13.16 ± 0.65 mEq/L and 9.83 ± 0.30 mEq/L, respectively. EEMS also showed a protective impact on the liver and kidneys of diabetic rats. Antihyperglycemic action was also discovered in diabetic animals. The findings of the current investigation demonstrated that ethanolic extract of M. sativa possesses anti-ulcer activity in diabetic rats. Ethanolic extract of M. sativa may be a treatment option for stomach ulcers that also have diabetes.

Phytoconstituents of two Gleditsia L. species and cytotoxic activity of the isolated curcumin analogues

Methanolic extracts of Gleditsia triacanthos L. fruits and Gleditsia caspica Desf. leaves yielded two mono-carbonyl curcumin analogues; (1E,4E)-1,5-bis(4-hydroxy-3-methoxyphenyl)penta-1,4-dien-3-one [1], (1E,4E)-1,5-bis(4-hydroxyphenyl)penta-1,4-dien-3-one [2], in addition to β-sitosterol [3], apigenin [4], quercetin-3`-O-methyl ether [5], rutin [6], quercetin [7], naringenin [8], eriodictyol [9], vitexin [10], isovitexin [11], gleditsin A [12]. The isolation of these compounds was reported here for the first time from the named plants. The separation and identification of curcumin analogues from genus Gleditsia in addition to 13C NMR data of compound 2 were reported here for the first time. Compounds 1 and 2 were assayed in two hepatic cancer cells; HepG-2 and Huh-7. Compound 1 showed high cytotoxic activity against HepG-2 with an IC50 value of 14.39 µM, compared with the standard, IC50 = 12.44 μM.

Variable expression of cyanide detoxification and tolerance genes in cyanogenic and acyanogenic white clover (Trifolium repens)

PREMISE

β-Cyanoalanine synthase (β-CAS) and alternative oxidase (AOX) play important roles in the ability of plants to detoxify and tolerate hydrogen cyanide (HCN). These functions are critical for all plants because HCN is produced at low levels during basic metabolic processes, and especially for cyanogenic species, which release high levels of HCN following tissue damage. However, expression of β-CAS and Aox genes has not been examined in cyanogenic species, nor compared between cyanogenic and acyanogenic genotypes within a species.

METHODS

We used a natural polymorphism for cyanogenesis in white clover to examine β-CAS and Aox gene expression in relation to cyanogenesis-associated HCN exposure. We identified all β-CAS and Aox gene copies present in the genome, including members of the Aox1, Aox2a, and Aox2d subfamilies previously reported in legumes. Expression levels were compared between cyanogenic and acyanogenic genotypes and between damaged and undamaged leaf tissue.

RESULTS

β-CAS and Aox2a expression was differentially elevated in cyanogenic genotypes, and tissue damage was not required to induce this increased expression. Aox2d, in contrast, appeared to be upregulated as a generalized wounding response.

CONCLUSIONS

These findings suggest a heightened constitutive role for HCN detoxification (via elevated β-CAS expression) and HCN-toxicity mitigation (via elevated Aox2a expression) in plants that are capable of cyanogenesis. As such, freezing-induced cyanide autotoxicity is unlikely to be the primary selective factor in the evolution of climate-associated cyanogenesis clines.

High temperature can improve the performance of invasive plants by facilitating root growth

PREMISE

The ever-increasing temperatures of the Anthropocene may facilitate plant invasions. To date, studies of temperature effects on alien plants have mainly focused on aboveground plant traits but ignored belowground traits, which may confound predictions of plant invasion risks.

METHODS

The temperature effects on the root growth dynamics of two alien shrubs, invasive Mimosa sepiaria and naturalized Corchorus capsulari, were studied using a 3D, transparent growth system under five temperature treatments (day/night: 18°C/13°C to 34°C/29°C) that cover the present and future warming temperature scenarios in China. We measured root depth and width growth in response to temperature treatments over 84 days. We also investigated intra- and interspecific competition of paired plants of the two species grown together at the five temperatures.

RESULTS

Shoot growth of M. sepiaria and C. capsularis was optimal at the mid-range temperature. Root growth, however, was faster at the highest temperature (34°C/29°C) for M. sepiaria, but decreased for C. capsularis as temperatures increased. Root depth growth was more sensitive than root width for both species during neighbor competition. Compared to C. capsularis, M. sepiaria had relatively greater advantage during intra- and interspecific competition with increasing temperature, possibly because of its better root growth at high temperatures.

CONCLUSIONS

These results suggest that temperature increases can improve the performance of some alien plants by facilitating width and depth growth of their roots. This enhancement requires serious attention when managing and predicting invasion risk.

Molecular phylogeny and evolution of inflorescence types in Eperua

PREMISE

The Amazonian hyperdominant genus Eperua (Fabaceae) currently holds 20 described species and has two strongly different inflorescence and flower types, with corresponding different pollination syndrome. The evolution of these vastly different inflorescence types within this genus was unknown and the main topic in this study.

METHODS

We constructed a molecular phylogeny, based on the full nuclear ribosomal DNA and partial plastome, using Bayesian inference and maximum likelihood methods, to test whether the genus is monophyletic, whether all species are monophyletic and if the shift from bat to bee pollination (or vice versa) occurred once in this genus.

RESULTS

All but two species are well supported by the nuclear ribosomal phylogeny. The plastome phylogeny, however, shows a strong geographic signal suggesting strong local hybridization or chloroplast capture, rendering chloroplast barcodes meaningless in this genus.

CONCLUSIONS

With our data, we cannot fully resolve the backbone of the tree to clarify sister genera relationships and confirm monophyly of the genus Eperua. Within the genus, the shift from bat to bee and bee to bat pollination has occurred several times but, with the bee to bat not always leading to a pendant inflorescence.

A bioactive chalcone from the aerial parts of Indigofera conferta Gillet

Ethnobotanical information indicates that Indigofera conferta is used in northern Nigeria for the management of poisonous snakebites and the methanol extract was previously reported to have antivenin activity. In this study, we report the isolation of an oxyprenylated bioactive secondary metabolite; 2',4'- dihydroxy-4-prenyloxychalcone from the chloroform fraction of the aerial parts of the plant's methanol extract and the in vivo evaluation of the compound against Naja nigricollis venom. The compound has demonstrated significant (p < 0.05) and dose-dependent antivenin activity against LD99 Naja nigricollis venom. At a dose of 10 mg/kg, the compound protected 60% of the animals tested from death. The observed activity lends credence to the traditional use of the plant in the management of snake bites in northern Nigeria. The compound, 2',4'- dihydroxy-4-prenyloxychalcone, could also serve as a lead in the development of novel antisnake venom agents.

Erythrina L. (Phaseoleae, Papilionoideae, Leguminosae) of Brazil: an updated nomenclatural treatment with notes on etymology and vernacular names

Erythrina L. is a genus that comprises ca. 120 to 130 species distributed throughout the tropics and subtropics of the world. Linnaeus established the genus in Genera Plantarum (1737) and the first binomial name given to a Brazilian Erythrina was E.crista-galli L., described by himself in Mantissa Plantarum (1767). Vellozo proposed in Florae Fluminensis (1790-1881) the first treatment of the genus in Brazil, where he treated three species from the states of Rio de Janeiro and São Paulo. Martins and Tozzi proposed the most recent treatment in 2018, where the authors recognized 11 valid names and presented three new synonyms. Despite extensive efforts already made in the genus, previous works did not treat all names related to the valid ones for Brazilian Erythrina. The present work is the most comprehensive and up-to-date nomenclatural treatment for the genus in Brazil, covering all 84 related names found on digital nomenclatural databases. Here we analyze 64 protologues, update typification statuses, propose five new synonyms, 13 new lectotypes (11 first-step, two second-step) and one neotype, linking all protologues and type specimens with their corresponding available digital sources, and make additional notes on etymology and vernacular names.

Chemical Composition and In Vitro Evaluation of Antioxidant and Antiproliferative Effects of Volatile Oils Hydrodistilled from Onobrychis carduchorum C.C. Towns., a Kurdish Traditional Plant

The volatile oils hydrodistilled from the aerial parts and roots of O. carduchorum C.C Towns. (Fabaceae) have been chemically characterized for the first time. A total of 43 constituents with an abundance >0.03% were identified and quantified in the two oils by GC/MS and GC/FID analyses. They comprise 38 components (98.58%) of the oil isolated from the aerial parts (OCA) and 34 components (93.33%) of the oil from the roots (OCR). Six constituents, α-pinene (23.11 ± 0.1%), β-elemene (17.33 ± 0.1%), 1,8-cineole (12.15 ± 0.2%), furfural (7.91 ± 0.1%), terpineol-4-ol (6.32 ± 0.2%), and limonene (4.13 ± 0.1%), accounted for about 75% of the total OCA oil. On the other hand, 1,8-cineole (15.79 ± 0.1%), furfural (10.44 ± 0.1%), β-elemene (10.14 ± 0.2%), α-terpineol (7.74 ± 0.1%), linalool (7.45 ± 0.1%), and α-pinene (4.76 ± 0.1%) made up about 60% of the OCR oil. The IC50 values of the scavenging activities of the OCA and OCR oils towards the DPPH radical and H2O2 were 79.8 ± 0.5 and 153.3 ± 0.6 μg/mL and 394.09 ± 0.2 and 311.67 ± 0.4 μg/mL, respectively. In addition, in the MTS assay, the OCA and OCR oils showed significant antiproliferative effects against T47D, MDA-MB-453, BG-1, and A549 human cancer cells that were more powerful than those against two normal human cell lines, HEK-293 and HFF-1. The abundant presence of β-elemene as an antiproliferative component of the two oils suggested the existence of a new chemotype of O. carduchorum.

Drought Tolerance of Legumes: Physiology and the Role of the Microbiome

Water scarcity and global warming make drought-tolerant plant species more in-demand than ever. The most drastic damage exerted by drought occurs during the critical growth stages of seed development and reproduction. In the course of their evolution, plants form a variety of drought-tolerance mechanisms, including recruiting beneficial microorganisms. Legumes (one of the three largest groups of higher plants) have unique features and the potential to adapt to abiotic stress. The available literature discusses the genetic (breeding) and physiological aspects of drought tolerance in legumes, neglecting the role of the microbiome. Our review aims to fill this gap: starting with the physiological mechanisms of legume drought adaptation, we describe the symbiotic relationship of the plant host with the microbial community and its role in facing drought. We consider two types of studies related to microbiomes in low-water conditions: comparisons and microbiome engineering (modulation). The first type of research includes diversity shifts and the isolation of microorganisms from the various plant niches to which they belong. The second type focuses on manipulating the plant holobiont through microbiome engineering-a promising biotech strategy to improve the yield and stress-resistance of legumes.