Improved genome assembly and pan-genome provide key insights into eggplant domestication and breeding

Eggplant (Solanum melongena L.) is an important horticultural crop and one of the most widely grown vegetables from the Solanaceae family. It was domesticated from a wild, prickly progenitor carrying small, round, non-anthocyanic fruits. We obtained a novel, highly contiguous genome assembly of the eggplant ‘67/3’ reference line, by Hi-C retrofitting of a previously released short read- and optical mapping-based assembly. The sizes of the 12 chromosomes and the fraction of anchored genes in the improved assembly were comparable to those of a chromosome-level assembly. We resequenced 23 accessions of S. melongena representative of the worldwide phenotypic, geographic, and genetic diversity of the species, and one each from the closely related species Solanum insanum and Solanum incanum. The eggplant pan-genome contained approximately 51.5 additional megabases and 816 additional genes compared with the reference genome, while the pan-plastome showed little genetic variation. We identified 53 selective sweeps related to fruit color, prickliness, and fruit shape in the nuclear genome, highlighting selection leading to the emergence of present-day S. melongena cultivars from its wild ancestors. Candidate genes underlying the selective sweeps included a MYBL1 repressor and CHALCONE ISOMERASE (for fruit color), homologs of Arabidopsis GLABRA1 and GLABROUS INFLORESCENCE STEMS2 (for prickliness), and orthologs of tomato FW2.2, OVATE, LOCULE NUMBER/WUSCHEL, SUPPRESSOR OF OVATE, and CELL SIZE REGULATOR (for fruit size/shape), further suggesting that selection for the latter trait relied on a common set of orthologous genes in tomato and eggplant.     

Leaf cuticular n-alkanes as markers in the chemotaxonomy of the eggplant (Solanum melongena L.) and related species

The complex of species formed by eggplant (Solanum melongena L.) and its wild and weedy relatives (mainly S. incanum L. and S. insanum L.) is characterised by an extreme morphological divergence that is not always associated with genetic variation. The taxonomy of so‐called ‘spiny Solanum’ species (subgenus Leptostemonum) is therefore extremely unclear. Cultivated eggplant lacks resistance to pests that frequently occur among the wild forms and species. As these wild plants are a potential gene pool for improvement of eggplant cultivars, knowledge of the characteristics of taxonomic relations between plants of different origin is crucial. We suggest using the leaf cuticular n‐alkane chain length distribution pattern as an alternative taxonomic marker for eggplant and related species. The results are in good agreement with current knowledge of the systematics of these plants; at the same time, the method developed here is useful for verifying plant identification based on morphological traits. Analysis of 13 eggplant cultivars, five accessions of S. incanum and two lines of S. macrocarpon enabled the intraspecific variation within eggplant to be assessed as low. There was wide variability among S. incanum accessions, probably because plants described as S. incanum are members of a number of different species. Some Asian accessions (sometimes described as S. insanum) were found to be almost identical to S. melongena, while a truly wild African S. incanum plant showed extensive similarity. The usefulness of the chemotaxonomic approach in dealing with the S. melongena–S. incanum complex is discussed.     

Haltbarkeit von Silagen und die sie beeinflussenden Faktoren

Content of p‐coumaric (PCA) and ferulic (FA) acid was determined by the HPLC method in fourteen forbs with a potential utilization as forages (range of nutrient content per kg DM: 100 to 244gCP, 339 to 528 g NDF and 180–369 g ADF. PCA and FA were determined after methanol extraction in four fractions: free phenolic acids extracted into ether, ester‐bound phenolic acids after alkaline hydrolysis, glycoside‐bound phenolic acids after acid hydrolysis, and cell wall‐bound phenolic acids after alkaline hydrolysis of the solid residue after the extraction with methanol.

Cell wall‐bound phenols were quantitatively the most important fraction (50% of total PCA and 47% of total FA, respectively). The differences among plant species in total PCA plus FA content were significant (F‐value 775, P < 0.01). The range of total phenol content was 31.3 to 416.3 mg/100g DM, the overall mean was 84 mg/100g DM.

Content of phenolic acids was correlated neither with ADF, NDF or ADL content (R ² = 1–3%, P > 0.05) nor with CP degradability (R ² = 3% and R ² = 1% for PCA and FA, respectively, P > 0.05).

95.4% and 30.9% of total PCA, and 98.3% and 72.5% of total FA disappeared in the rumen from the sample of Glechoma hederacea (species with the highest phenol content) and from the sample of Galium aparine (species with low phenol content), respectively, within the four hour incubation interval.

It is presumed that in comparison with grasses, PCA and FA concentration in tested forbs represents a much lower risk in potential ruminant nutrition.     

Clone-specific responses in leaf phenolics of willows exposed to enhanced UVB radiation and drought stress

The effects of enhanced UVB radiation and drought stress on willow secondary phenolics were studied using the leaves of 8‐week‐old micropropagated plantlets from interspecific hybrids (Salix myrsinites L. ×S. myrsinifolia Salisb.) and pure species (S. myrsinifolia). The plantlets were subjected for 4 weeks to two levels of UVB radiation (ambient, enhanced) and two levels of watering (well‐watered, drought‐stressed) according to a 2 × 2 factorial design. Enhanced UVB radiation increased the total concentration of flavonoids and phenolic acids in all plantlets, while the total concentration of salicylates remained unaffected. Drought stress reduced the total concentration of salicylates and phenolic acids in S. myrsinifolia plantlets, while in hybrids only phenolic acids were affected. The response of phenolic acids to enhanced UVB in drought‐stressed plantlets was different from that in well‐watered ones, indicating that drought stress limited the accumulation of phenolic acids under enhanced UVB radiation. Flavonoids increased in response to enhanced UVB radiation in drought‐stressed plantlets, although drought caused serious physiological stress on growth. There were significant differences between hybrid and S. myrsinifolia plantlets with respect to the composition of phenolics and between families and clones with respect to their concentration. In addition, the response of salicylates, flavonoids and phenolic acids to enhanced UVB and drought stress was clone‐specific, which may indicate that climatic changes will alter the genetic composition of northern forests.     

Allozyme variation in the eggplant,Solanum melongena L. (Solanaceae)

Enzyme electrophoretic studies were made in cultivated Solanum melongena L. (eggplant) and similar wild and weedy forms, several of which have been thought to be different species/taxa. Twenty-nine accessions of S. melongena, 33 accessions of weedy forms (referred to as insanum) and 2 accessions of wild forms (referred to as incanum) were surveyed for 29 isozyme loci. In S. melongena, 22 of the 29 loci were monomorphic, and nearly all of its genes were either also monomorphic or in similar frequencies in insanum and incanum. The results demonstrate that the three taxa have a very close genetic relationship. The high genetic identities between them (0.913–0.967) suggests that they are conspecific even though they include extensive morphological diversity.     

Diversity of Enzyme Electrophoretic Patterns in the Eggplant Complex

Studies on electrophoretic patterns of five enzymes, aspartate aminotransferase (AAT), glucose-phosphate isomerase (GPI), glutamate dehydrogenase (GDH), shikimate dehydrogenase (SKDH) and triose-phosphate isomerase (TPI) resulted in the identification of 17 phenotypes in 21 accessions of Solanum melongena L, S. insanum L and S. incanum L. The results provided evidence of 10 isozyme loci represented by 20 alleles involved in the control of the above enzymes. GPI and AAT showed high number of phenotypes, while GDHpresented a single morpho The most frequent phenotypes were identical in S. melongena, S. insanum and S. incanum indicating close genetic proximity of the three taxa. S. melongena accessions showed high degree of zymogram homogeneity, while the other two species were more diverse.     

Cadmium accumulation in relation to organic acids in leaves of Solanum nigrum L. as a newly found cadmium hyperaccumulator

The influence of various cadmium concentrations on organic acid levels in leaves of the Cd hyperaccumulator, Solanum nigrum L. and a closely related species, Solanum melongena L., were investigated. In particular, the relationship of organic acids with Cd accumulation in the two plants was investigated. The results showed that Cd accumulation in the shoots of S. nigrum was significantly higher than that of S. melongena. The accumulation of Cd in the leaves of S. nigrum ranged from 2.0 to 167.8 μg g⁻¹ dry weight (DW), but only from 1.2 to 64.0 μg g⁻¹ DW in S. melongena. Solanum melongena was considerably less tolerant to Cd than S. nigrum. Approximately 20% of the total Cd in S. nigrum leaves was water-soluble, suggesting that some accumulated Cd was associated with water-soluble compounds such as organic acids. Malic acid in the leaves of S. nigrum was the most abundant organic acid [up to 115.6–145.7 μmol g⁻¹ fresh weight (FW)], but this acid was not significantly affected by the Cd concentration in soil. However, the level of malic acid in S. melongena plants was much lower, only 16.3–75.4 μmol g⁻¹ FW. The significant positive correlations between total Cd and water-soluble Cd concentrations and both acetic and citric acid concentrations in the leaves of S. nigrum were observed. In contrast, there was no correlation between concentrations of the two acids and Cd concentrations in the leaves of S. melongena. These results indicated that acetic and citric acids in the leaves of S. nigrum might be related to its Cd hyperaccumulation.     

Effect of some mould inhibitors and herbal plants on mycotoxins production by Aspergillus flavus and Fusarium verticilloides in vitro and in stored corn grains

Clove oil, clove extract and butylated hydroxyanisole (BHA) completely suppressed the growth of both Fusarium verticilloides and Aspergillus flavus isolates. Black cumin and thyme extracts were more suppressive on F. verticilloides than A. flavus. Antitox-Plus (AP) had no effect on the growth of both the pathogens. The minimum inhibitory concentration (MIC) test revealed that A. flavus was more sensitive to Fix-A-Tox (FAT) and AP than F. verticilloides. In the growth media, all the tested substances, completely suppressed the production of aflatoxins by A. flavus and significantly reduced fumonisins production by F. verticilloides, particularly clove oil and extract. Treatment of immature grains with the tested mould inhibitors prior to inoculation with A. flavus and F. verticilloides significantly reduced mycotoxins production at the end of the storage period; moreover, highest reduction rates were realised by BHA and FAT. Complete or highly significant suppression of aflatoxins in mature grains were obtained by all the tested herbal and synthetic mould inhibitors. Ground clove buds contained the highest carvacrol content, whereas thymol content was higher in thyme extract. Clove oil was rich in eugenol. Alpha-tocopherol content was higher in ground black cumin (BC), followed by BC oil. Unsaturated fatty acid content was higher in thyme extract and ground BC than saturated fatty acids. Linolenic acid was the most predominant fatty acid in BC oil and extract, whereas behenic and arachidic acids were detected only in BC oil. Stearic acid was the main fatty acid in clove oil and extract, whereas oleic acid was the prevailing fatty acid in thyme extract.     

The chemical composition,antifungal, antioxidant and antimutagenicity properties of bioactive compounds from fungal endophytes associated with Thai orchids

Some plant‐derived bioactive compounds produced by fungal endophytes have been proven to have antimicrobial and antioxidant activities. In this study, endophytic fungi were isolated from 20 orchid samples collected in northern Thailand from 12 genera of orchids. In total, 97 isolates were isolated from the leaves (44.3%), stems (40.2%) and flowers (15.5%) of the orchid samples. The antifungal activity was investigated of the endophytic isolates against the plant pathogenic fungi. The results showed that 13 endophytic isolates provided antifungal activities against Fusarium sp., Colletotrichum sp. and Curvularia sp. The endophyte CK F05‐5, which was isolated from the flower part of Dendrobium lindleyi, was chosen for further testing because it the highest level of antifungal activity against Fusarium sp. The isolate CK F05‐5 was identified as Fusarium oxysporum on the basis of its ITS sequences of 5.8 s rRNA, and phytochemical analysis revealed the presence of coumarins. The ethyl acetate extract of CK F05‐5 was examined for its total phenolic content and antioxidant activity using Folin–Ciocalteu's reagent and 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging assay, respectively. The phenolic content was 160.51 mg of GAE/g of extract, and the free radical scavenging activity was 89.61 µg/ml at the half maximal inhibitory concentration (IC₅₀). The antimutagenic potential of the ethyl acetate extract of CK F05‐5 against Trp‐P‐1 mutagenic substances was determined using the Ames test which revealed that the extract of CK F05‐5 at 10 mg/plate had the highest antimutagenic activity against Trp‐P‐1 (51.2%) and 39.6% for strains TA98 and TA100, respectively. The active compounds present in the acetate extract of CK F05‐5 were examined using GC‐MS analysis, which displayed the presence of gibepyrone A, pyrrolo [1, 2‐a] pyrazine‐1, 4‐dione, hexahydro‐3‐(2‐methylpropyl) and indoleacetic acid as major components. Based on the results, this endophytic fungus contains various bioactive components that have various biological activities. This useful information could help in producing potentially valuable and novel pharmaceutical products.     

Hybridization and fertility of hybrid derivatives of Solatium melongena L. and Solanum macrocarpon L.

Summary Eleven genotypes of Solanum melongena L. and one genotype tentatively identified as Solanum macrocarpon were reciprocally intercrossed. Three patterns of the crossability were determined: a) reciprocally crossable, b) reciprocally non-crossable, and c) unidirectionally crossable. In toto 524 F₁ interspecific hybrids were grown during one season under open pollination conditions in the field. A large proportion of the F₁ hybrids produced seed set. The highest degree of seed set was recorded in the reciprocal F₁ hybrid of S. melongena (cv. Burpee Hybrid) and S. macrocarpon (Acc. 21–73). In addition, a limited number of back-cross progeny have been produced. The germinating seeds produced an F₂ generation of which some recombinants showed a considerably higher degree of fertility than the F₁. This finding suggests the possibility of the transfer of genes for resistance to two-spotted spider mite from S. macrocarpon to S. melongena.This research was performed as part of NJAES Project No. 99201 (NE-9) supported by the New Jersey Agricultural Experiment Station and Regional Hatch Funds. Paper of the Journal Series of the New Jersey Agricultural Experiment Station. Please address reprint requests to Dr. C. Boyer     

芦苇腐解土中酚酸类化感物质的水分响应特性研究

芦苇和虉草均具有较强的去污能力,常作为湿地植物配置于同一人工湿地进行污水处理。芦苇作为一种强化感植物对虉草具有较强的化感作用,在自然湿地和人工湿地中均会出现芦苇代替虉草的现象,且这一现象的发生与土壤含水量存在一定联系,此外,芦苇腐解土对虉草的化感抑制效应与腐解土中总酚酸的量密切相关。为了研究芦苇腐解土中主要酚酸类物质的水分响应特性,筛选出其中对水分响应较为明显的酚酸物质种类,该研究采用高效液相色谱法,通过芦苇枯落物腐解土的制备,对不同水分环境下芦苇腐解土中酚酸类物质进行了分离和鉴定。结果表明:芦苇腐解土中可分离出没食子酸、香豆酸、香草酸、丁香酸、对香豆酸、阿魏酸、水杨酸和苯甲酸等8种酚酸类物质,其中香豆酸、苯甲酸和阿魏酸等3种酚酸类物质含量较高。分离出的8种酚酸类物质的含量与腐解土的相对含水量均呈显著线性负相关关系,即随着腐解土相对含水量的上升,酚酸类物质的含量均呈现下降趋势,且各种酚酸类物质对水分的响应趋势均可用线性方程较好地拟合。其中,香豆酸、没食子酸和阿魏酸对芦苇腐解土的水分响应最为明显。因此,可将香豆酸、没食子酸和阿魏酸作为主要调控目标,通过调控湿地土壤中水分含量,削弱芦苇对虉草的化感抑制效应,从而维持人工湿地中虉草芦苇群落的长期稳定共存。     

Essential‐Oil and Fatty‐Acid Composition,and Antioxidant Activity of Extracts of Ficaria kochii

The essential‐oil and fatty‐acid composition of the aerial parts of Ficaria kochii (Ledeb .) Iranshahr & Rech .f. native to Iran, and the antioxidant activity of various extracts of this plant were examined. The study by GC‐FID and GC/MS analysis of the essential oil resulted in the identification of 61 compounds, representing 86.01% of the total oil composition. Phytol (10.49%), farnesol (7.72%), methyl linoleate (5.57%), and α‐farnesene (4.96%) were the main components. The fatty‐acid composition of the aerial parts of F. kochii was also analyzed by GC/MS. The major components were palmitic acid (25.9%), linolenic acid (25.3%), and linoleic acid (17.5%). Polyunsaturated fatty acids (PUFAs) were found in higher amounts than saturated fatty acids. The possible antioxidant activity of various extracts (prepared by using solvents with different polarity) of the F. kochii aerial parts was evaluated by screening for their 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical‐scavenging activity, Fe^III‐reducing power, total antioxidant activity, and inhibitory activity in the linoleic acid‐peroxidation system. H₂O proved to be the most efficient solvent for the extraction of antioxidants, as the H₂O extract contained the highest amount of phenolic compounds (2.78±0.23 GAE/g dry matter) and also exhibited the strongest antioxidant capacity in all the assays used. The results of the present investigation demonstrated that the aerial parts of F. kochii can be used as natural and safe nutrition supplement in place of synthetic ones.     

Genetic Diversity,Population Structure,and Resistance to Phytophthora capsici of a Worldwide Collection of Eggplant Germplasm

Eggplant (Solanum melongena L.) is an important solanaceous crop with high phenotypic diversity and moderate genotypic diversity. Ninety-nine genotypes of eggplant germplasm (species (S. melongena, S. incanum, S. linnaeanum and S. gilo), landraces and heirloom cultivars) from 32 countries and five continents were evaluated for genetic diversity, population structure, fruit shape, and disease resistance to Phytophthora fruit rot. Fruits from each line were measured for fruit shape and evaluated for resistance to two Phytophthora capsici isolates seven days post inoculation. Only one accession (PI 413784) was completely resistant to both isolates evaluated. Partial resistance to Phytophthora fruit rot was found in accessions from all four eggplant species evaluated in this study. Genetic diversity and population structure were assessed using 22 polymorphic simple sequence repeats (SSRs). The polymorphism information content (PIC) for the population was moderate (0.49) in the population. Genetic analyses using the program STRUCTURE indicated the existence of four genetic clusters within the eggplant collection. Population structure was detected when eggplant lines were grouped by species, continent of origin, country of origin, fruit shape and disease resistance.     

BACE1 (Beta‐Secretase) Inhibitory Phenolic Acids and a Novel Sesquiterpenoid from Homalomena occulta

Four phenolic acids, namely 2‐[(Z)‐heptadec‐11‐enyl]‐6‐hydroxybenzoic acid ( 1 ), 2‐[(6Z,9Z,12Z)‐heptadeca‐6,9,12‐trienyl]‐6‐hydroxybenzoic acid ( 2 ), 2‐[(9Z,12Z)‐heptadeca‐9,12‐dienyl]‐6‐hydroxybenzoic acid ( 3 ), and 2‐hydroxy‐6‐(12‐phenyldodecyl)benzoic acid ( 4 ), and one sesquiterpene, asperpenoid ( 5 ), were isolated from the 95% EtOH extract of the roots of Homalomena occulta, among which 1, 2 , and 5 represent new compounds. Further, the phenolic acids 1 – 4 exhibited BACE1 (β‐secretase) inhibitory activity with IC₅₀ values of 6.23±0.94, 6.28±0.63, 7.93±0.38, and 7.65±0.62 μM , respectively.     

Phenolic compounds (hydroxycinnamic acids,flavan-3-ols,flavonols) profile in fruit of Italian peach varieties

Interest in phenolic compounds of fruit is growing due to their positive effects on reducing the risk of cardiovascular and carcinogen diseases. The role of the flesh colour, of the tissue (exocarp or mesocarp) and of the cultivar on the content of phenolic compounds (hydroxycinnamic acids, flavan-3-ols, flavonols) was evaluated in peach, Prunus persica (L.) Batsch, with a HPLC-DAD analysis, on 10 varieties deriving from the Italian breeding programmes, never previously characterized by this approach. The flavan-3-ols (catechin, epicatechin and procyanidin B1) were the most abundant class of phenolic compounds in peach cultivars analysed. Among hydroxycinnamic acids, neochlorogenic and chlorogenic acids were also identified and measured in the peach cultivars analysed. Quercetin-3-O-rutinoside was the only flavonol found in the exocarp of all the cultivars evaluated, but in the mesocarp of only some cultivars. Content of phenolic compounds was confirmed to be strongly dependent on the cultivar and, in general, the content was significantly higher in exocarp than in mesocarp. An overall significant difference in phenolic compounds as associated with flesh colour was not observed.     

Changes in Cell Wall-bound Phenolic Compounds and Lignin in Roots of Date Palm Cultivars Differing in Susceptibility to Fusarium oxysporum f. sp. albedinis

The roots of date palm contain four cell wall‐bound phenolic acids identified as p‐hydroxybenzoic, p‐coumaric, ferulic and sinapic acids. The ferulic acid represents the major phenolic compound since it constitutes 48.2–55.8% of cell wall‐bound phenolic acids. All these phenolic acids were present in the resistant cultivar (BSTN) and the susceptible cultivar (JHL). However, the pre‐infection contents of p‐coumaric, ferulic and sinapic acids were greater in the resistant cultivar than in the susceptible one. For the contents of p‐hydroxybenzoic acid, there was no significant difference between the resistant cultivar and the susceptible cultivar. Similarly, the pre‐infection contents of lignin were approximately equal for both cultivars. Inoculation of the date palm roots by Fusarium oxysporum f. sp. albedinis induced important modifications to the contents of the cell wall‐bound phenolic compounds and lignin, which made it possible to distinguish between resistant and susceptible cultivars. The post‐infection contents of cell wall‐bound phenolic compounds underwent a rapid and intense increase with a maximum accumulation on the tenth day for p‐hydroxybenzoic acid (1.54 μmol/g), p‐coumaric acid (2.77 μmol/g) and ferulic acid (2.64 μmol/g) and on the fifteenth day for sinapic acid (1.85 μmol/g). The maximum contents accumulated in the resistant cultivar were greater than those in the susceptible cultivar, namely, 11 times for p‐hydroxybenzoic acid, 2.6 times for p‐coumaric acid, 1.8 times for ferulic acid and 12.3 times for sinapic acid. In the susceptible cultivar, p‐coumaric acid and ferulic acid contents also increased after inoculation although they did not reach the pre‐infection contents of the resistant cultivar. The contents of p‐hydroxybenzoic acid in the susceptible cultivar roots did not present post‐infection modification and those of sinapic acid decreased instead. The lignin contents increased in both cultivars with a maximum accumulation on the fifteenth day. However, the maximum contents accumulated in the resistant cultivar roots were 1.5 times greater than those of the susceptible cultivar. These results showed clear differences between the resistant BSTN and the susceptible JHL cultivars. The implication of cell wall‐bound phenolic compounds and lignin in the resistance of date palm to F. oxysporum f. sp. albedinis appears to be dependent on the speed and intensity of their accumulation with greater contents in the first stage of infection.     

Phenolic compounds of Sorghum vulgare in response to Sclerotium rolfsii infection

Abstract

Identification of individual phenolic acids of Sorghum vulgare Pers. cv. M.P. after interaction with Sclerotium rolfsii Sacc. using high performance liquid chromatograph (HPLC) showed the presence of phenolics namely tannic, gallic, ferulic, chlorogenic and cinnamic acids in varying amounts. After 72 h inoculation with S. rolfsii, a maximum amount of ferulic acid (166.6 µg g^?1 fresh wt) was present in the collar of inoculated plants, followed by leaves and roots and its level decreased gradually with time. Similarly, the presence of chlorogenic acid was traced after 48 h, while that of cinnamic acid was traced after 72 h of inoculation. Reddish-brown pigmentation at the collar region of inoculated plants was also observed along with the high content of tannic acid. Among other phenolics, the presence of gallic acid was recorded consistently and maximum accumulation (139.3 µg g^?1 fresh wt) was noticed at the zone of interaction (collar region) after 72 h of inoculation. In contrast, maximum lignin deposition was observed at collar region after 96 h of inoculation. Induction of phenolic acids in S. vulgare along with the lignin deposition and red pigmentation at collar region is considered a key biomarker in the non-host-pathogen interaction in the S. valgare–S. rolfsii pathosystem.     

Allelopathic activity of different plant parts of <Emphasis Type="Italic">Peganum harmala</Emphasis> L. and identification of their growth inhibitors substances

This study was conducted to evaluate the inhibitory potential of P. harmala leaf, stem and root extract on germination and growth of Avena fatua L. and Convolvulus arvensis L., as well as identification of the phytotoxic substances responsible for this activity. According to our results, the degree of toxicity of different P. harmala plant parts can be arranged in the following order: leaves > stems > roots. The two test species differed in their sensitivity to P. harmala extracts. Inhibitory effect on shoot length and seedling dry weight was more pronounced in C. arvensis, whereas higher reduction in germination, root length and total chlorophyll content occurred in A. fatua. A significant amount of water-soluble phenolic acids were found in P. harmala plant extracts. Total phenolic acids content was higher in leaf extracts when compared to that of stem or root extracts. Seven phenolic acids including gallic acid, vanillic acid, 4-hydroxybenzoic acid, 3,4-dihydroxybenzoic acid, caffeic acid, syringic acid and ferulic acid were found in P. harmala leaf extracts. On the other hand, we identified four phenolic acids from stem (galllic acid, vanillic acid, 3,4-dihydroxybenzoic acid and caffeic acid) and root (galllic acid, 4-hydroxybenzoic acid, syringic acid and cinnamic acid) extracts. The greater number of growth inhibitors detected in the leaves might explain the stronger inhibitory activity. Overall, our results suggest that P. harmala might be used as a natural herbicide for weed control and consequently reduce dependence on synthetic herbicides.     

Wild Relatives of the Eggplant (Solanum melongena L.: Solanaceae): New Understanding of Species Names in a Complex Group

Background

The common or brinjal eggplant (Solanum melongena L.) belongs to the Leptostemonum Clade (the “spiny” solanums) of the species-rich genus Solanum (Solanaceae). Unlike most of the genus, the eggplant and its relatives are from the Old World; most eggplant wild relatives are from Africa. An informal system for naming eggplant wild relatives largely based on crossing and other biosystematics data has been in use for approximately a decade. This system recognises several forms of two broadly conceived species, S. incanum L. and S. melongena. Recent morphological and molecular work has shown that species-level differences exist between these entities, and a new species-level nomenclature has been identified as necessary for plant breeders and for the maintenance of accurately named germplasm.

Methodology/Principal Findings

We examined herbarium specimens from throughout the wild species ranges as part of a larger revision of the spiny solanums of Africa. Based on these morphological and molecular studies, we delimited species in the group to which the common eggplant belongs and constructed identification keys for the group. We also examined the monophyly of the group considered as the eggplant relatives by previous authors.

Conclusions/Significance

We recognise ten species in this group: S. aureitomentosum Bitter, S. campylacanthum A.Rich., S. cerasiferum Dunal, S. incanum L., S. insanum L., S. lichtensteinii Willd., S. linnaeanum Hepper & P.-M.L.Jaeger, S. melongena L., S. rigidum Lam. and S. umtuma Voronts. & S.Knapp. We review the history of naming and provide keys and character lists for all species. Ploidy level differences have not been investigated in the eggplant wild relatives; we identify this as a priority for improvement of crop wild relative use in breeding. The application of species-level names to these entities will help focus new collecting efforts for brinjal eggplant improvement and help facilitate information exchange.