Nigrum Plants Research Articles

Polyaspartate and liquid amino acid fertilizer are appropriate alternatives for promoting the phytoextraction of cadmium and lead in Solanum nigrum L

Traditional metal chelators, such as ethylenediaminetetraacetic acid (EDTA), have been gradually replaced due to their poor biodegradability in soil and high risk of heavy metal leaching into groundwater, which pose high environmental risks to the health of humans and animals. In this study, a liquid amino acid fertilizer (LAAF, waste proteins from hydrolysates of animal carcasses) and polyaspartate (PASP) were used as additives to enhance the phytoextraction of cadmium (Cd) and lead (Pb) from contaminated soil. We conducted pot experiments to investigate the phytoextraction capacity of Solanum nigrum, a Cd accumulator, grown on soil highly contaminated with Cd and Pb in the absence (as controls) or presence of PASP and LAAF. Both PASP and LAAF significantly improved plant growth, Cd accumulation, and total Cd and Pb content in S. nigrum shoots and roots. PASP and LAAF application promoted Cd translocation from roots to shoots in S. nigrum and Cd bio-accessibility in rhizosphere soils, but this was not the case for Pb. Both PASP and LAAF increased Cd and Pb phytoextraction by S. nigrum plants, and Cd phytoextraction was more effective in LAAF-assisted S. nigrum than in PASP-assisted S. nigrum. These findings demonstrate that the low cost and ecofriendly features of recycled waste proteins make them good candidates for chelant-enhanced phytoextraction from heavy metal-contaminated soils.

Identification of candidate genes involved in steroidal alkaloids biosynthesis in organ-specific transcriptomes of Veratrum nigrum L.

Veratrum nigrum is protected plant of Melanthiaceae family, able to synthetize unique steroidal alkaloids important for pharmacy. Transcriptomes from leaves, stems and rhizomes of in vitro maintained V. nigrum plants were sequenced and annotated for genes and markers discovery. Sequencing of samples derived from the different organs resulted in a total of 108,511 contigs with a mean length of 596 bp. Transcripts derived from leaf and stalk were annotated at 28%, and 38% in Nr nucleotide database, respectively. The sequencing revealed 949 unigenes related with lipid metabolism, including 73 transcripts involved in steroids and genus-specific steroid alkaloids biosynthesis. Additionally, 3203 candidate SSRs markers we identified in unigenes with average density of one SSR locus every 6.2 kb sequence. Unraveling of biochemical machinery of the pathway responsible for steroidal alkaloids will open possibility to design and optimize biotechnological process. The transcriptomic data provide valuable resources for biochemical, molecular genetics, comparative transcriptomics, functional genomics, ecological and evolutionary studies of V. nigrum.

Effects of copper oxide nanoparticles to Solanum nigrum and its potential for phytoremediation

The significant use of copper oxide nanoparticles (CuO NPs) has generated worries over their impacts on the ecosystem and human health due to their release from numerous products to the environment. The Solanum nigrum L. is recognized as a phytoremediation plant and may survive within the excessive metal-stressed surroundings. Five CuO NPs levels were evaluated for their impacts on the callus of S. nigrum. Fresh, dry weight, water content, free amino acids, and potassium content of callus cells were significantly decreased due to the impact of CuO NPs. We also observed increased levels of malondialdehyde, bound phenolic compounds, soluble carbohydrates and enzymatic activity of peroxidase, and polyphenol oxidase in callus cells supplying conditions for the lowering of oxidative stress triggered by CuO NPs. Phenylalanine ammonia lyase, soluble proteins and free phenolic compounds in callus cells were increased under 50, 100 and 150 mg/L CuO NPs and were significantly decreased in most cases by the application of the highest concentration (200 mg/L) of CuO NPs. The catalase activity in calli didn’t clearly change via CuO NPs stress. Further, Cu accumulation in the callus was increased with increasing levels of CuO NPs in the medium (50–200 mg/L), as evidenced through 10.3, 17.0, 20.9 and 40.4-fold, respectively, as compared with the control. The FT-IR analysis showed alterations in most macromolecules such as phenolic compounds, lipids, proteins, carbohydrates, cellulose, and hemicellulose in callus cells-treated with CuO NPs. From these results, we can conclude that S. nigrum plants can be used to remediate the medium contaminated with CuO NPs because the plant can accumulate the metal and has a response to defend itself from the metal stress. The potential of Solanum nigrum to tolerate CuO NPs to assure its possible utilize in phytoextraction and purifying of NPs contaminated soils paving the way for the cultivation of such areas.

Study on selenium accumulation characteristics of different ploidies Solanum nigrum

The selenium accumulation characteristics of Solanum nigrum with different ploidy were studied by the pot experiment, and the biomass, selenium content and selenium accumulation of diploid (Solanum photeinocarpum), tetraploid (Solanum photeinocarpum) and hexaploid (Solanum nigrum) plants were determined, the results showed that there was a difference between the biomass and selenium content of three kinds of ploidy plants of S. nigrum. The biomass of various organs and shoots of hexaploid S. nigrum plants was significantly higher than that of tetraploid and diploid plants. In terms of selenium content and selenium accumulation, the hexaploid plants had the highest selenium content and selenium accumulation in stems, leaves and shoots. After comprehensive comparison, the hexaploid S. nigrum has large biomass and strong selenium-enriching ability, so it can be used as an excellent plant material for soil selenium absorption and transformation.

Study on cadmium accumulation characteristics of Solanum nigrum with different ploidies

To study the cadmium accumulation characteristics of Solanum nigrum with different ploidies, the biomass, cadmium content and cadmium accumulation of diploid (Solanum photeinocarpum), tetraploid (Solanum photeinocarpum) and hexaploid (Solanum nigrum) were measured by a pot experiment. The results showed that the biomass of roots, stems, leaves and shoots of S. nigrum plants with different ploidy all ranked as follows: hexaploid > tetraploid > diploid. Cadmium content and cadmium accumulation in stems, leaves and shoots of hexaploid plants were significantly higher than those in tetraploid and diploid plants, and the cadmium translocation factor and translocation accumulation factor of hexaploid were the largest, too. Therefore, hexaploid S. nigrum had a highest ability to extract and transport cadmium, which can be used as an ideal plant for remediation of cadmium-contaminated soil.

First Report of Natural Infection of Solanum nigrum with Tomato mosaic virus in India

Solanum nigrum Linn. (Family Solanaceae) is an edible green leafy vegetable, widely consumed and cultivated on a commercial scale in southern India. It is highly prized for its medicinal properties. S. nigrum is found to harbor several groups of viruses viz., begomoviruses, orthotospoviruses, potyviruses, tobraviruses, etc., under field conditions, and therefore acts as a reservoir host. Symptoms such as mosaic mottling, crinkling, curling and distortion of leaves were observed in S. nigrum plants(cv Local) in the commercially cultivated fields of Coimbatore and Salem districts of Tamil Nadu, India during March 2016. Disease incidence ranged between 15 and 20% based on a survey conducted in ten fields each from both districts. Leaf dip preparations of symptomatic samples collected from the infected plants were analyzed by transmission electron microscopy and characteristic, typical rigid rod-shaped tobamovirus-like particles of ~300 ×18nm size were visualized. Six symptomatic leaf samples collected from 2...

Evaluation of Aristolochia indica L. and Piper nigrum L. methanol extract against centipede Scolopendra moristans L. using Wistar albino rats and screening of bioactive compounds by high pressure liquid chromatography: a polyherbal formulation

The present study was aimed to explore the anti-venom activity of Aristolochia indica and Piper nigrum plants against the centipede (Scolopendra moristans) envenomation in animal model. In vtiro phytochemical, antioxidant and blocking of proteolysis were carried out by using standard spectrophotometric methods. In vivo anti-venom activity of methanol extracts was determined using Wistar albino rats after fixing lethal and effective doses. The electrolytes, lipid, liver, kidney, hematological parameters were analyzed and histopathology of skin and liver were also examined. Anti-skin cancer by MTT method and HPLC analysis were also carried out. The CAIPN extract showed higher total phenolics (150.65 ± 0.08 mg GAE/g extract) and flavonoids (158.97 ± 0.93 mg RE/g extract) content. Further, the same extract revealed the higher molybdenum reducing, inhibition of lipid peroxidation (80.08 ± 0.22%), DPPH radical scavenging (3.05 μg/mL), and blocking of proteolysis activities (96.45 ± 0.04%). The parameters like hypersensitivity, electrolytes, lipids, blood components, liver and kidney marker of the CAIPN methanol extract (200 mg/kg) treated envenomated rats was remarkable and same as in the normal animals. Such status was also achieved by RBAI and SPN at 600 mg/kg. The histopathological scoring of skin and liver confirmed the venom neutralizing activity of CAIPN. Also, the CAIPN methanol extract was notable in anti-skin cancer activity (208 μg/mL). The presence of the ferulic acid (04 ± 0.09 μg/mg) and quercetin (35.30 ± 0.30 μg/mg) like compounds was confirmed by HPLC analysis. Hence, the present investigation results conclude that the CAIPN was significant in their action and this polyherbal formulation could be considered as a new source for the pharmaceutical industries to develop a new effective, ecofriendly anti-venom drug.

Host-plant patch qualities and presence of a likely competitor species affect the distribution and abundance of a rare British moth, Cucullia lychnitis

Understanding the environmental factors that affect the distribution and abundance of rare and threatened species can help identify priority sites for conservation action such as habitat management. The moth Cucullia lychnitis is identified in UK legislation as a priority species for conservation. Its conspicuous larvae feed on a patchily distributed host plant Verbascum nigrum, but are entirely absent from some host plant patches within the species’ range. Environmental variability among patches was investigated to understand factors affecting (i) patch occupancy by C. lychnitis and (ii) abundance of C. lychnitis, where present. Occupancy of individual V. nigrum plants within occupied patches was also investigated. The likelihood of patch occupancy increased with patch size, and decreased with patch isolation. Abundance of C. lychnitis was negatively correlated with patch isolation and with abundance of the weevil Cionus nigritarsis, which exploits the same host plant and may be a competitor. Within occupied patches, larvae of C. lychnitis were significantly more likely to be found on taller plants with more flower spikes; such plants are typical of established rather than newly-created patches. These results may help to guide efforts to conserve C. lychnitis, highlighting the importance of habitat connectivity and indicating potential management actions to promote features positively associated with larval incidence and abundance.

Culturable endophytic fungal diversity in the cadmium hyperaccumulator Solanum nigrum L. and their role in enhancing phytoremediation

In this study, the endophytic fungal community associated with Solanum nigrum was isolated and characterized for cadmium (Cd) tolerance and host plant growth modulation under Cd contamination for the first time. In total, 42 culturable endophytic fungal isolates representing various morphotypes were isolated, among which 14 different genera of the fungal phylum Ascomycota were identified based on the analysis of the internal transcribed spacer (ITS) region of the rRNA gene. Among the identified genera, Colletotrichum (18%) represented the dominant genus followed by Alternaria (14%), and Fusarium (14%). The majority of the endophytic isolates were sensitive to a lower concentration (0.5mM) of Cd. However, Glomerella truncata PDL-1, and Phomopsis fukushii PDL-10 showed the highest tolerance to a concentration gradient of Cd (0.5⿿2mM). Owing to the levels of Cd tolerance detected, in order to simulate a tripartite plant-microbe-metal interaction, S. nigrum plants were inoculated with PDL-1 and PDL-10 under Cd spiking of 0, 5, 15, and 25mgkg⿿1. The results indicated that PDL-10 inoculated plants had significantly higher Cd content in shoots as well as in roots than observed in the PDL-1 inoculated plants. Additionally, irrespective of Cd stress, PDL-1 and PDL-10 inoculation significantly improved plant growth attributes such as shoot and root length, chlorophyll content, and fresh and dry shoot/root weight as compared to those of non-inoculated control plants. The results of this study highlight the possible role of fungal endophytes harbored inside S. nigrum, which has the potential to improve the efficiency of phytoremediation or phytostabilization in the cleanup of Cd-contaminated soil.

Seasonal phenology of Tuta absoluta (Lepidoptera: Gelechiidae) in protected and open-field crops under Mediterranean climatic conditions

The population structure and dynamics of the tomato leafminer Tuta absoluta were investigated in a protected tomato crop and on potato and tomato crops and Solanum nigrum plants under open-field Mediterranean climatic conditions (Sardinia) by captures in pheromone-baited traps and visual inspection of host plants. In the greenhouse crop, male captures and leaf infestation were low in winter and increased steadily in spring up to 797.3 males/trap/week and 6.4 mines/leaf, respectively. Under open-field conditions, males were captured all year round with a peak in early September, concurrently with highest mean daily temperatures. Pest density in potato crops was very low (<0.3 mines/leaf), as well as on S. nigrum (0.16 mines/leaf). Conversely, high pest infestation was observed in tomato leaves (3.8 mines/leaf) and fruits (27% damaged fruits). Eggs, larvae and adults were detected over two consecutive winters, indicating that T. absoluta can develop continuously over the year under natural conditions. Parasitoids were recorded throughout the survey at low rates (≤16.1%). The most active beneficials were Necremnus tutae and Neochrysocharis formosa in protected and open-field crops, respectively. The tomato leafminer completed 6 generations in the greenhouse tomato crop during the winter-spring growing season, whereas in open-field crops the pest completed two generations on winter potato and 4-5 in spring-summer tomato. The degree-day model based on minimum and maximum temperatures reliably described the population dynamics in the protected crop, and estimated the completion of 7.4 generations per year under open-field Mediterranean conditions.

Hyperaccumulation activity and metabolic responses of Solanum nigrum in two differentially polluted growth habitats

The present study was conducted to evaluate the pollution phytoremediation capacity and pollution tolerance of Solanum nigrum in two habitats varied in their pollution intensity with heavy metals. We investigated the relative contributions of the hyperaccumulator S. nigrum in eliminating some pollutants from agricultural soils such as Zn, Pb, Ni and Cd in Tanta and in the sewage water irrigated area at El-Gabal El-Asfar (GA) region. The study also concluded that heavy metals pollution resulted in a significant amendment in the primary and secondary metabolic pathways of the plant. The exposure of S. nigrum to heavy metals pollution in GA region resulted in a relative accumulation in soluble sugars, soluble proteins and free amino acids in the plant root, stem and leaves, but their levels in berry were to some extent inferior to those of Tanta region. In addition, the exposure of S. nigrum plants to sewage water effluents in GA region improved the accumulation of osmoprotectant and antioxidant molecules such as proline, glycine betaine, flavonoids and phenolic compounds. Moreover, the medicinally active alkaloids have accumulated in response to sewage irrigation in various organs of GA region plants comparable with those of Tanta region.

Improvement in phytoremediation potential of Solanum nigrum under cadmium contamination through endophytic-assisted Serratia sp. RSC-14 inoculation.

The growth of hyperaccumulator plants is often compromised by increased toxicity of metals like cadmium (Cd). However, extraction of such metals from the soil can be enhanced by endophytic microbial association. Present study was aimed to elucidate the potential of microbe-assisted Cd phytoextraction in hyperaccumulator Solanum nigrum plants and their interactions under varied Cd concentrations. An endophytic bacteria Serratia sp. RSC-14 was isolated from the roots of S. nigrum. In addition to Cd tolerance up to 4mM, the RSC-14 exhibited phosphate solubilization and secreted plant growth-promoting phytohormones such as indole-3-acetic acid (54μg/mL). S. nigrum plants were inoculated with RSC-14 and were grown in different concentrations of Cd (0, 10, and 30mg Cdkg(-1) sand). Results revealed that Cd treatment caused significant cessation in plant growth, biomass, and chlorophyll content, whereas significantly higher malondialdehyde (MDA) and electrolyte production in leaves were observed in a dose-dependent manner. Conversely, RSC-14 inoculation relived the toxic effects of Cd-induced stress by significantly increasing root/shoot growth, biomass production, and chlorophyll content and decreasing MDA and electrolytes contents. Ameliorative effects on host growth were also observed by the regulation of metal-induced oxidative stress enzymes such as catalase, peroxidase, and polyphenol peroxidase. Activities of these enzymes were significantly reduced in RSC-14 inoculated plants as compared to control plants under Cd treatments. The lower activities of stress responsive enzymes suggest modulation of Cd stress by RSC-14. The current findings support the beneficial uses of Serratia sp. RSC-14 in improving the phytoextraction abilities of S. nigrum plants in Cd contamination.

Study of liquid culture system for micropropagation of the medicinal plant Solanum nigrum L. and its effect on antioxidant property

Solanum nigrum Linn., known for hepatoprotective and antioxidant properties, is extensively harvested from the wild. Supply is far short of demand, necessitating requirement of efficient in vitro propagation protocols. Nodal explants from wild S. nigrum plants were cultured in vitro in MS medium supplemented with 3.0 mg L−1 IAA, 0.5 mg L−1 BAP and gelled with 0.8 % agar. After 30 days, shoots buds were transferred to liquid MS medium of same composition. Subsequent subculture was carried out every 6 days. Shoot doubling time in solid and liquid media was calculated. Total phenolics, proanthocyanidin and flavonoid contents, ABTS.+ and hydrogen peroxide radical scavenging antioxidant capacity of wild and in vitro aqueous leaf extracts were estimated and compared. In MS agar, 18 shoot buds were produced per explant after 30 days of culture, with shoot doubling time of 7.11 days. In liquid media, 21 shoots per explant were produced in 6 days, with a 5-fold higher multiplication rate and shoot doubling time of 1.37 days. Leaves were morphologically similar to those of wild plants. Total phenolics, proanthocyanidin and flavonoid contents of in vitro leaf extracts was 5–10 times higher than that of wild plants while ABTS.+ and H2O2 radical scavenging activity was similar in both extracts. Liquid media is better suited for in vitro propagation of S. nigrum since enhanced multiplication rate was observed with shorter subculture intervals. Moreover, plants retained normal morphology and antioxidant property.

Histological and ultrastructural evidence for zinc sequestration in Solanum nigrum L.

The accumulation of contaminants in the environment due to anthropogenic activities is a matter of global concern. Solanum nigrum L. plants, able to accumulate zinc and hyperaccumulate cadmium, were challenged with 0.025g Zn L(-1) during 35days. The localization of Zn in roots, stems and leaves of S. nigrum plants was evaluated by autometallography (AMG) in order to determine the specific tissue, cell and subcellular compartments of Zn sequestration. This Zn concentration resulted in stunted plant growth but no other symptoms of Zn toxicity. Zinc concentration in the plants was highest in the roots, 666mg Zn kg(-1) fresh weight (f.w.), and lower in the stems, 318mg Zn kg(-1) f.w., and leaves, 101mg Zn kg(-1) f.w. Roots of Zn-treated plants showed an underdeveloped structure but additional layers of proliferating cortical parenchyma cells. AMG of S. nigrum roots, stems and leaves revealed a generalized Zn distribution associated with the cell walls in all tissues. In the vasculature (xylem and phloem), Zn was observed at the plasma membrane-cell wall complex of vascular parenchyma cells and conducting elements. Conspicuous Zn deposits were detected in the vacuoles of cortical parenchyma and starch sheath, as well as in the tonoplast of the mesophyll cells. Our results suggest that Zn flux through the plant occurs via the xylem and phloem and associated parenchyma until it is conducted to permanent storage sites, namely, the apoplast and vacuoles of cortical parenchyma cells of the root, stem and the leaf mesophyll.

Photo-Fenton plus Solanum nigrum L. weed plants integrated process for the abatement of highly concentrated metalaxyl on waste waters

The treatment of a highly concentrated pesticide and systemic fungicide solution, containing metalaxyl as active compound (150mgL−1), was investigated by using the photo-Fenton process in combination with Solanum nigrum L. weed plants. High concentration of metalaxyl has a destructive effect on S. nigrum plants although this pesticide can be successfully degraded by the photo-Fenton process. S. nigrum seed germination and seedling development were not affected by iron species at concentrations lower than 11mgL−1, which is well above the optimal dosage for the photo-Fenton process (4mgL−1). In addition, at the referred optimal dosage, S. nigrum growth was not affected and those plants were able to extract large amounts of iron species from the solution (between 1.5–2.0 and 0.2–0.5mg of Fe per gram of dry weight of plant in their roots and shoots, respectively). Negative effects on biomass production and chlorophyll and carotenoids contents, used as stress biomarkers, were not detected. When S. nigrum plants were directly exposed to the solution pre-treated by the photo-Fenton process, an increase in glutathione-S-transferase activity in shoots, some toxicity towards the plant physiology and a decrease in the total soluble protein content, in both shoots and roots, were observed; nevertheless, the plant growth was still remarkable. These results suggest that the photo-Fenton process can be used as a chemical primary treatment, followed by S. nigrum plants biological remediation (as post-treatment) for waste waters that are contaminated with concentrations of metalaxyl as high as 150mgL−1.

Leaf Anthracnose, a New Disease of Swallow-Worts Caused by Colletotrichum lineola from Russia.

Black swallow-wort, Vincetoxicum nigrum (L.) Moench (= Cynanchum louiseae Kartesz & Gandhi), and pale swallow-wort, V. rossicum (Kleopow) Borhidi (= Cynanchum rossicum (Kleopow) Borhidi), are invasive plants belonging to the family Apocynaceae and are the targets of biological control efforts to control their spread in the United States. In 2010, a disease on a related species, V. scandens Sommier & Levier, was observed in the Krasnodar area of Russia. Disease symptoms were many small, dark red-to-purple leaf spots, approximately 2 to 5 mm in diameter, with white centers. Leaf spots were found on the upper leaf surface. Leaf tips and margins of leaves bearing many of these spots were necrotic. Symptomatic leaves were collected and sent to the BSL-3 containment facility at the Foreign Disease-Weed Science Research Unit (FDWSRU) of the USDA, ARS in Frederick MD. Surface-disinfested symptomatic leaves were incubated at 20 to 25°C in sterile moist chambers. After several days, acervuli and brown setae were observed inside the leaf spots. Pure cultures, designated FDWSRU 10-002, were obtained by transferring spore masses with sterile glass needles onto 20% V8 juice agar. Seeds of V. scandens, collected in Russia, were placed in a freezer at -20°C for 6 weeks and then germinated in sterile petri plates on moist filter paper. The seedlings were then transplanted and grown in a 20°C greenhouse under 12 h of light. Koch's postulates were fulfilled as follows: 2-month-old plants each of V. scandens, V. nigrum, and V. rossicum were inoculated with spores from 2-week-old cultures of isolate 10-002. Plants were inoculated by spraying an aqueous suspension of 106 spores per ml onto each plant until all leaves were wet. Plants were placed in 20 to 24°C dew chambers for 18 h and then placed in a 20°C greenhouse. Two weeks later, diseased leaves with the same symptoms observed in the field were harvested from each species, and the fungus was reisolated from seven of seven inoculated V. scandens plants, one of two V. nigrum plants, and four of four V. rossicum plants. Measurements of fungus fruiting structures were taken from cultures grown on synthetic nutrient-poor agar (SNA) (1). Conidiophores were brown, septate, and branched. Conidia were one-celled, hyaline, smooth walled, ovoid to oblong, falcate, and 20.1 to 26.2 × 1.7 to 3.6 μm (mean ± s.d. = 23.5 ± 1.3 × 2.6 ± 0.4 μm). Lengths of the conidia conformed to the description of Colletotrichum lineola Corda (1), but the conidia were slightly narrower than described. To induce appressoria formation, approximately 104 conidia were placed on sterile dialysis membranes on top of SNA in petri dishes that were wrapped in foil and incubated at 24°C for 24 h. After this time, appressoria were observed with a microscope at ×400 magnification. The appressoria were dark brown, smooth walled, ellipsoidal, and 5.5 to 25.5 × 3.6 to 12.1 μm (mean ± s.d. = 13.4 ± 4.0 × 7.3 ± 2.1 μm), which conformed to the description of appressoria of C. lineola Corda (1). DNA sequences of ITS1, 5.8S, and ITS2 were submitted to GenBank (No. HQ731491), and after BLAST analysis, aligned 100% to 15 previously identified isolates of C. lineola in GenBank. Voucher specimens of the fungus have been deposited in the U.S. National Fungus Collection and were designated as BPI 881105 and BPI 881106. Host range and efficacy tests are planned to determine the suitability of C. lineola for biological control of swallow-worts in the United States. Reference: (1) U. Damm et al. Fungal Divers. 39:45, 2009.

JA‐Ile signalling in Solanum nigrum is not required for defence responses in nature

Jasmonate signalling plays a central role in activating the plethora of responses that are elicited by herbivory. Solanum nigrum plants silenced in the expression of genes involved in jasmonic acid biosynthesis (irlox3), conjugation (irjar4) and perception (ircoi1) were used to study the function of these genes in the field and in the regulation of transcriptional and metabolic responses. In the field, damage from Noctuidea larvae was four- to fivefold higher on irlox3 and ircoi1 than on wild-type (WT) plants, whereas damage to irjar4 plants was similar to WT levels. Damage rates reflected plant survival rates; fewer irlox3 (78%) and ircoi1 (22%) plants survived compared with irjar4 and WT plants of which all plants survived. Gene expression profiling in leaves 3 h after simulated herbivory revealed differential regulation of ∼700 genes in irlox3 and ircoi1 plants but of only six genes in irjar4 compared with WT plants. Surprisingly, transcriptional responses were not reflected in metabolomic responses; 48 h after simulated herbivory, irjar4 plants showed a 50% overlap in their metabolic profile with ircoi1 plants. Together, these results reveal that SnJAR4 does not play a direct role in herbivore defence, but suggests that SnJAR4 is involved in responses other than those to herbivory.

Regulation of jasmonate metabolism and activation of systemic signaling in Solanum nigrum: COI1 and JAR4 play overlapping yet distinct roles

• Jasmonates are ubiquitous messengers in land plants essential for the activation of defense responses. However, their signaling properties, accumulation and metabolism vary substantially among species. Solanum nigrum is a wild Solanaceous species developed as a model to study defense responses. • Solanum nigrum plants transformed to silence the expression of key genes in jasmonate production (SnLOX3), conjugation (SnJAR4) and perception (SnCOI1) were generated to analyze the function of these genes in jasmonate accumulation and metabolism (studied by a combination of LC-MS/MS and (13) C-isotope labeling methods) and in signaling [studied by the systemic elicitation of leucine aminopeptidase (LAP) activity]. • In contrast with the early single jasmonic acid (JA) burst induced by wounding in wild-type (WT) plants, elicitation with insect oral secretions induced a later, second burst that was essential for the induction of systemic LAP activity, as demonstrated by ablation experiments. This induction was dependent on SnLOX3 and SnCOI1, but not on SnJAR4. In addition, the local accumulation of JA-glucose and JA-isoleucine was dependent on SnCOI1, whereas the accumulation of hydroxylated jasmonates was dependent on both SnCOI1 and SnJAR4. • The results demonstrate that SnLOX3, SnCOI1 and SnJAR4 have overlapping yet distinct roles in jasmonate signaling, differentially controlling jasmonate metabolism and the production of a systemic signal.

Chill unit models for blackcurrant ( Ribes nigrum L.) cultivars ‘Ben Gairn’, ‘Ben Hope’ and ‘Ben Tirran’

Temperate-zone crops require a period of winter chilling to terminate dormancy and ensure adequate bud break the following spring. The exact chilling requirement of blackcurrant ( Ribes nigrum), a commercially important crop in northern Europe, is relatively unknown. Chill unit models have been successfully utilized to determine the optimum chilling temperature of a range of crops, with one chill unit equating to 1 h exposure to the optimum temperature for chill satisfaction. Two-year-old R. nigrum plants of the cultivars ‘Ben Gairn’, ‘Ben Hope’ and ‘Ben Tirran’ were exposed to temperatures of −10.1 °C, −3.4 °C, 0.1 °C, 1.5 °C, 2.1 °C, 3.4 °C or 8.9 °C (±0.7 °C) for durations of 0, 2, 4, 6, 8 or 10 weeks and multiple regression analyses used to determine the optimum temperature for chill satisfaction.

EDDS and EDTA-enhanced zinc accumulation by solanum nigrum inoculated with arbuscular mycorrhizal fungi grown in contaminated soil

The effect of two different chelating agents [EDTA and EDDS ( S, S-ethylenediaminedissucinic acid)] on Zn tissue accumulation in Solanum nigrum L. grown in a naturally contaminated soil was assessed. Under those conditions, the response of the plant to the inoculation with two different isolates of arbuscular mycorrhizal fungi (AMF) – Glomus claroideum and Glomus intraradices – was also studied. Plants grown in the local contaminated soil (Zn levels of 433 mg kg −1) accumulated up to 1191 mg kg −1 of Zn in the roots, 3747 mg kg −1 in the stems and 3409 mg kg −1 in the leaves. S. nigrum plants grown in the same soil spiked with extra Zn (Zn levels of 964 mg kg −1) accumulated up to 4735, 8267 and 7948 mg Zn kg −1 in the leaves, stems and roots, respectively. The addition of EDTA promoted an increase in the concentration of Zn accumulated by S. nigrum of up to 231% in the leaves, 93% in the stems and 81% in the roots, while EDDS application enhanced the accumulation in leaves, stems and roots up to 140, 124 and 104%, respectively. In the stems, the presence of Zn was predominantly detected in the cortex collenchyma cells, the starch sheath and the internal phloem and xylem parenchyma, and the addition of chelating agents did not seem to have an effect on the localisation of accumulation sites. The devise of a chelate-enhanced phytoextraction strategy, using chelating agents and AMF, is discussed.