Glucosinolates in Diplotaxis and Eruca leaves: diversity, taxonomic relations and applied aspects

Leaf glucosinolates of 42 Diplotaxis and 21 Eruca accessions were studied. Total content ranged from 0.25 to more than 70 g kg(-1) dry wt. The 13 clusters, defined on the basis of glucosinolate composition, belonged to two glucosinolate-rich groups, characterised by the prevalence of a single component, and one low-glucosinolate group, with a profile not dominated by any individual component. A sinigrin-rich cluster (D. ibicensis, D. berthautii, D. ilorcitana, D. siettiana, D. tenuisiliqua, D. brevisiliqua, and D. virgata) and a gluconapin-rich cluster (D. catholica, D.siifolia, D. virgata, and D. ollivieri) included all the species previously classified in the nigra phylogenetic lineage. D. virgata was confirmed to be a critical taxon, with one accession slightly diverging from the others. D. siifolia subsp. vicentina was separated from the others in a glucobrassicin-rich cluster. D. harra, a rather isolated representative of sub-genus Hesperidium, clustered together D. assurgens in a sinalbin-rich cluster. Another well defined cluster was represented by D. brachycarpa (gluconasturtin). The two sub-species of D. erucoides were well differentiated by their glucosinolate profile. The low glucosinolate species: D. tenuifolia, D. viminea, D. cretacea, D. muralis (subgenus Diplotaxis), and E. vesicaria, all previously included in the rapa/oleracea lineage, belonged to seven less defined clusters, mainly differing on the presence/absence or the relative abundance of some components (glucoraphanin, glucolepidin, 4-hydroxy-glucobrassicin, 4-phenylbutyl gls, glucoerucin and neoglucobrassicin). The data support previous taxonomic works. Glucosinolate-rich taxa, with well characterised profiles may be suitable for industrial uses, whereas the variability of edible D. tenuifolia and E. vesicaria may represent a basis for breeding horticultural types.     

Variation in defences of the plant Barbarea vulgaris and in counteradaptations by the flea beetle Phyllotreta nemorum

Several sorts of variation in the interaction between the insect, Phyllotreta nemorum L. (Coleoptera:Chrysomelidae:Alticinae), and the plant, Barbarea vulgaris R.Br. (Brassicaceae), have been discovered: 1) genetic differences in the levels of defences in the plant, 2) genetic differences in the ability of insects to cope with the plant defences, 3) seasonal variation in levels of defences in the plant, and 4) differences between leaf types in levels of defences.Two plant accessions were suitable for larval development throughout the season while the remaining nine accessions were more or less unsuitable for larvae from the susceptible T-population at least at certain times of the year. All accessions were suitable for the resistant E-population throughout the year. There was a seasonal variation in levels of defences in some accessions which were unsuitable for the T-population during the summer period when beetles were present, but not during autumn and spring when the beetle were hibernating. Upper (younger) cauline leaves of these accessions had higher levels of defences than lower (older) cauline leaves. The resistant E-population used B. vulgaris as a natural host plant while the susceptible T-population did not. The use of B. vulgaris as a natural host plant by the E-population of P. nemorum seems to be an extension of the host plant range of the species. Variation in plant defences may have facilitated the switch in host plant use by the resistant flea beetle population.     

Biogeographical analysis of the flea beetle genus Chaetocnema in the Afrotropical Region: distribution patterns and areas of endemism

Aim The areal distributions of Chaetocnema species in the Afrotropical Region have been analysed with the aims of determining the distribution patterns (chorotypes) and identifying the most important areas of endemism for this flea beetle genus in sub‐Saharan Africa. Location Data were collected in sub‐Saharan Africa, including Madagascar. Methods The Afrotropical Region was divided into 103 5° quadrats (operative geographical units, or OGUs). A presence–absence matrix of the Afrotropical Chaetocnema species in the OGUs was analysed by cluster analysis (Baroni Urbani & Buser index and the WPGMA clustering method) to generate distribution pattern data based on similarity of distribution. The most important areas of endemism were identified by parsimony analysis of endemicity. Results The general distribution of Chaetocnema in the Afrotropical Region was found to be associated with moist environments and montane grasslands. Most species exhibit restricted geographical ranges. Cluster analysis revealed 120 spatial distributions that can be grouped into 13 distinct distribution patterns (chorotypes). The most important areas of endemism for Chaetocnema in sub‐Saharan Africa according to the present parsimony analysis of endemicity are: (1) central and eastern Madagascar [endemicity rate (ER) = 61.1%], (2) Western Cape Province (ER = 36.4%), (3) southern Drakensberg (ER = 26.7%), (4) the Shaba Region (ER = 16.7%), and (5) the North‐Kivu Region (ER = 5.0%). Main conclusions There are 123 known species of Chaetocnema in the Afrotropical Region, more than in any other zoogeographical region. About 91% of the species are endemic and they generally exhibit a restricted and often very localized geographical range. The remaining 9% of the species are represented by seven species that also inhabit northern Africa and/or the Arabian peninsula (C. bilunulata Demaison, C. ganganensis Bechyné, C. ljuba Bechyné, C. pulla Chapuis, C. tarsalis Wollaston, and C. wollastoni Baly), three species that widely inhabit the Palaearctic Region (C. conducta (Motschulsky), C. schlaeflini (Stierlin), and C. tibialis (Illiger)), and two species that were introduced (C. confinis Crotch, and C. picipes Stephens).     

Isoferuloyl derivatives of five seed glucosinolates in the crucifer genus Barbarea

Five acylated glucosinolates (GSLs) were isolated as desulfated derivatives after enzymatic desulfation of anionic metabolites from seeds of two chemotypes of Barbareavulgaris, and their structures were elucidated by a combination of spectroscopic methods and HPLC analysis of products of enzymatic de-acylation. The acyl group was in all cases found to be a trans isoferuloyl group at the 6′-position of the thioglucose moiety. The GSL moieties of the native metabolites were found to be one Trp derived; indol-3-ylmethylGSL, as well as four homoPhe derived; phenethylGSL, (S)-2-hydroxy-2-phenylethylGSL, (R)-2-hydroxy-2-phenylethylGSL, and (R)-2-hydroxy-2-(4-hydroxyphenyl)ethylGSL. GSL analysis of B. vulgaris seed extracts by the commonly employed ‘desulfoGSL’ method (based on binding to anion exchange columns, enzymatic desulfation, elution and HPLC) was optimized for 6′-isoferuloyl derivatives of GSLs. From peak areas before and after de-acylation of the isolated desulfoGSL, the response factor of the 6′-isoferuloyl derivative of (S)-2-hydroxy-2-phenylethylGSL was estimated to be 0.37 (relative to 1.00 for sinigrin), allowing us to estimate the level in B. vulgaris to 3 μmol/g dry wt. in mature seeds and less than 0.1 μmol/g dry wt. in seedlings and floral parts of the insect resistant G-type of B. vulgaris var. arcuata. HPLC analysis of intact GSLs in crude extracts and after group separation did not reveal additional derivatives, but confirmed the existence of the deduced intact GSLs. A taxonomic screen showed that most (14/17) B. vulgaris accessions (with the exception of three accessions of var. vulgaris) contained relatively high levels of 6′-isoferuloyl GSLs. The profiles of 6′-isoferuloylated GSLs matched the profiles of non-acylated GSLs in the same seed accessions, suggesting a low side chain specificity of the isoferuloylation mechanism. A minor peak tentatively identified as a dimethoxycinnamoyl derivative of (S)-2-hydroxy-2-phenylethylGSL was detected by HPLC-MS of one accession, suggesting that GSLs with other acyl groups may occur at low levels. A single analyzed B. plantaginae accession contained relatively high levels of 6′-isoferuloylated phenethylGSL and (S)-2-hydroxy-2-phenylethylGSL. Five other tested Barbarea species (B. australis, B. bracteosa, B. intermedia, B. stricta, B. verna) also contained isoferuloylated GSLs, albeit at lower levels than in B. vulgaris and B. plantaginae, suggesting that seed GSL acylation is a general character of the Barbarea genus and possibly also of related genera including Arabidopsis.     

Phylogeny of Isatis (Brassicaceae) and allied genera based on ITS sequences of nuclear ribosomal DNA and morphological characters

Systematics of the genus Isatis (Brassicaceae) is difficult and controversial, and previous studies were based solely on morphological characters. Sequence variation of the internal transcribed spacer (ITS) regions and the 5.8S gene of nuclear ribosomal DNA (nrDNA) were analyzed using parsimony and Bayesian methods. Twenty-eight taxa of Isatis and related genera of the tribe Isatideae were sampled, including 20 Isatis species representing almost all major morphological lineages, all three species of Pachypterygium, two of nine species of Sameraria, and monospecific Boreava, Myagrum, and Tauscheria. Two well-supported clades were resolved in the ITS tree, and they demonstrate the artificiality of the present delimitation of the tribe. One clade includes I. emarginata, I. minima, I. trachycarpa, P. brevipes, P. multicaule, P. stocksii, and T. lasiocarpa. The second clade includes I. buschiana, the polymorphic I. cappadocica with five subspecies, I. gaubae, I. kotschyana, I. leuconeura, I. pachycarpa, I. takhtajanii, I. tinctoria, and S. armena. Pachypterygium is polyphyletic and, together with Boreava, Sameraria, and Tauscheria, all are nested within Isatis. This study is a continuation of our recent systematic survey based on seed-coat microsculpturing ( Moazzeni et al., 2007. Flora 202, 447–454) and reveals that fruit characters mapped onto the molecular tree show considerable convergence. The reliance on fruit characters alone in the delimitation of genera may well lead to erroneous phylogenetic results and thus to incorrect taxonomic conclusions.     

Effects of leaf pubescence in Salix borealis on host- plant choice and feeding behaviour of the leaf beetle, Melasoma lapponica

Density of leaf trichomes in Salix borealis affected both the choice of individual host plants and feeding behaviour of adults and last instar larvae of the willow feeding leaf beetle, Melasoma lapponica. Beetles clearly preferred shaved disks to unshaved ones taken from the same leaf; this preference was highest in leaves of the most pubescent plants. High leaf pubescence explained the low preference for willow clones from the high density site in among-site preference trials; shaving significantly increased the consumption of these pubescent willow clones. In no-choice experiments, the food consumption by both adults and last instar larvae decreased with an increase in leaf pubescence. The time budget of adults did not depend on leaf pubescence of the host plants, however adults compelled to feed on highly pubescent plants changed their feeding sites twice as often as on less pubescent willow clones. Larvae feeding on highly pubescent plants spend moving three times as much time as larvae feeding on less pubescent plants. Combined with our earlier observations on the increase in leaf pubescence in the year(s) following defoliation, these data suggest that leaf hairiness may have contributed to the delayed induced resistance in S. borealis by disturbing the feeding behaviour of M. lapponica.     

Characterization and chromosome location of satellite DNA in the leaf beetle Chrysolina americana (Coleoptera, Chrysomelidae)

This paper is the first record of the satellite DNA of the specialized phytophagous genus Chrysolina. The satellite DNA of Chrysolina americana is organized in a tandem repeat of monomers 189 bp long, has a A + T content of 59.6 % and presents direct and inverted internal repeats. Restriction analysis of the total DNA with methylation sensitive enzymes suggests that this repetitive DNA is undermethylated. In situ hybridization with a biotinylated probe of the satellite DNA showed the pericentromeric localization of these sequences in all meiotic bivalents. The presence of this repetitive DNA in other species of the genus was also tested by Southern analysis. The results showed that this satellite DNA sequence is specific to the C. americana genome and has not been found in three other species of Chrysolina with a different choice of host plants than in the former. This revised version was published online in July 2006 with corrections to the Cover Date.     

A taxonomic revision of the genus Sinotrisus Yin & Li (Coleoptera, Staphylinidae, Pselaphinae)

The genus Sinotrisus Yin & Li, comprising four species, is redefined and revised. Members of Sinotrisus are often found with ants of the subfamily Formicinae, or in humid forest habitats. The type speciesand three new species are (re-)described and illustrated: Sinotrisus kishimotoi Yin & Nomura, sp. n. (China: Sichuan), Sinotrisus nomurai Yin, Li & Zhao (type species) (China: Zhejing), Sinotrisus sinensis Yin & Nomura, sp. n. (China: Sichuan) and Sinotrisus vietnamensis Yin & Nomura, sp. n. (Vietnam: Lai Chau). A key is included as an aid to distinguishing these species.     

Flower color-flower scent associations in polymorphic Hesperis matronalis (Brassicaceae)

Floral scent emission rate and composition of purple and white flower color morphs of Hesperis matronalis (Brassicaceae) were determined for two populations and, for each, at two times of day using dynamic headspace collection and GC-MS. The floral volatile compounds identified for this species fell into two main categories, terpenoids and aromatics. Principal component analysis of 30 compounds demonstrated that both color morphs emitted more scent at dusk than at dawn. Color morphs varied in chemical composition of scent, but this differed between populations. The white morphs exhibited significant differences between populations, while the purple morphs did not. In the white morphs, one population contains color-scent associations that match expectations from classical pollination syndrome theory, where the flowers have aromatic scents, which are expected to maximize night-flying moth pollinator attraction; in the second population, white morphs were strongly associated with terpenoid compounds. The potential impact that pollinators, conserved biosynthetic pathways, and the genetics of small colonizing populations may have in determining population-specific associations between floral color and floral scent are discussed.     

Non‐random segregation of an autosomal gene in males of the flea beetle,Phyllotreta nemorum: implications for colonization of a novel host plant

The flea beetle, Phyllotreta nemorum (L.) (Coleoptera: Chrysomelidae: Alticinae), is currently expanding its host plant range in Europe. The ability to utilize a novel host plant, Barbarea vulgaris R. Br. (Brassicaceae), is controlled by major dominant genes named R‐genes. The present study used extensive crossing experiments to illustrate a peculiar mode of inheritance of the R‐gene in a population from Delemont (Switzerland). When resistant males from Delemont are mated with recessive females from a laboratory line, the female F₁ offspring contains the R‐allele and is able to utilize B. vulgaris, whereas the male offspring contains the r‐allele and is unable to utilize the plant. This outcome suggests X‐linkage of the R‐gene, but further crossing experiments demonstrated that this was not the case. When the R‐gene is present in offspring from males from a laboratory line that originates from Taastrup (Denmark), it is transmitted to female and male offspring in equal proportions as a normal autosomal gene. The results demonstrate a polymorphism in segregation patterns of an autosomal R‐gene in P. nemorum males. Males from Delemont contain a factor which causes non‐random segregation of the R‐gene (NRS‐factor). This factor is inherited patrilineally (from fathers to sons). Males with the NRS‐factor transmit the R‐gene to their female offspring, whereas males without the NRS‐factor transmit the R‐gene to female and male offspring in equal proportions. Various models for the non‐random segregation of autosomes in P. nemorum males are discussed – e.g., fusions between autosomes and sex chromosomes, and genomic imprinting. The implications of various modes of inheritance of R‐genes for the ability of P. nemorum populations to colonize novel patches of B. vulgaris are discussed.     

Foliar cuticular alkanes of Camarea (Malpighiaceae) and their taxonomic significance

Camarea is a South-American endemic genus comprising eight species. In the present work n-alkanes from foliar cuticular waxes of 23 specimens, representing seven species of Camarea were analyzed, aiming at establishing interspecific affinities and evaluating the usefulness of n-alkane distribution as species characteristic. The sampling included also specimens of Peixotoa reticulata and Janusia guaranitica (both Malpighiaceae). The results were used to obtain a phenogram indicating chemical affinities between species. The results are in agreement with morphological similarities among some Camarea species. Intraspecific variability was small, suggesting that n-alkane distribution may be useful for species characterization and establishment of links among Camarea species. The results support the recognition of Camarea triphylla as a synonym of Camarea axillaris and are not coherent with a hybrid condition of a population exhibiting morphological characteristics combining Camarea affinis and Camarea hirsuta, suggesting instead that the individuals analyzed belong either to Camarea hirsuta or a close species. Distribution of n-alkanes is inadequate to distinguish among Malpighiaceae genera: P. reticulata has n-alkane distribution similar to several Camarea species.     

A new flea of the genus Ctenidiosomus (Siphonaptera,Pygiopsyllidae) from Salta Province,Argentina

A new species of flea of the genus Ctenidiosomus Jordan, 1931 (Siphonaptera: Pygiopsyllidae) is described from Phyllotis osilae J. A. Allen, 1901, from Salta Province, Argentina. This is the first time that Ctenidiosomus has been recorded in Argentina. A key to species of males of Ctenidiosomus is presented.     

Flavonol pentaglycosides of Cordyla (Leguminosae: Papilionoideae: Swartzieae): distribution and taxonomic implications

A survey of foliar flavonoids in the swartzioid legume genus Cordyla s.l. revealed that three species, C. haraka, C. pinnata and C. richardii, were rich in flavonol pentaglycosides. Their structures were elucidated by spectroscopic and chemical methods as the 3-O-alpha-l-rhamnopyranosyl(1-->3)-alpha-l-rhamnopyranosyl(1-->2)[alpha-l-rhamnopyranosyl(1-->6)]-beta-d-galactopyranoside-7-O-alpha-l-rhamnopyranosides of quercetin and kaempferol (cordylasins A and B, respectively). These compounds were not found in the remaining species, C. africana, C. densiflora, C. madagascariensis (two subspecies) and C. somalensis, which exhibited different profiles of flavonoid glycosides. The distribution of flavonol pentaglycosides in Cordyla s.l. does not support a recent proposal to place both C. haraka and C. madagascariensis in the genus Dupuya [Kirkbride, J.H., 2005. Dupuya, a new genus of Malagasy legumes (Fabaceae). Novon 15, 305-314]. The generic relationship between Cordyla s.l. and Mildbraediodendron is also reassessed on the basis of chemical characters, as the O-linked tetrasaccharide that characterises cordylasins A and B is the same as that found in mildbraedin (kaempferol 3-O-alpha-l-rhamnopyranosyl(1-->3)-alpha-l-rhamnopyranosyl(1-->2)[alpha-l-rhamnopyranosyl(1-->6)]-beta-d-galactopyranoside), the main foliar flavonoid of Mildbraediodendron excelsum. Mildbraedin itself was found to be a minor constituent of leaflet extracts of C. haraka, C. pinnata and C. richardii, and a major constituent of C. somalensis.     

New species, new records and new morphological characters of the genus Tillicera Spinola from China (Coleoptera, Cleridae, Clerinae)

Two new species of the genus Tillicera Spinola, 1841 from China are described and illustrated: Tillicera sensibilissp. n. from Yunnan (also from Myanmar, Thailand and Laos) and Tillicera weniisp. n. from Taiwan. Tillicera bibalteata Gorham, 1892, Tillicera hirsuta (Pic, 1926) and Tillicera michaeli Gerstmeier & Bernhard, 2010 are newly recorded from China. Tillicera auratofasciata (Pic, 1927) is newly recorded in some provinces of China. A key to species of the genus from China is provided. Relationships between species are discussed with emphasis on characters of male phallus, female internal reproductive organs and pit-like sensilla in male terminal antennomere, which is discovered in Tillicera for the first time. The present generic definition of Tillicera is discussed as well. Photos of terminalia of the previously known species are also provided for comparison.     

Geographic and evolutionary diversification of glucosinolates among near relatives of Arabidopsis thaliana (Brassicaceae)

Glucosinolates are biologically active secondary metabolites that display both intra- and interspecific variation in the order Brassicales. Glucosinolate profiles have not been interpreted within a phylogenic framework and little is known regarding the processes that influence the evolution of glucosinolate diversity at a macroevolutionary scale. We have analyzed leaf glucosinolate profiles from members of the Brassicaceae that have diverged from Arabidopsis thaliana within the last 15 million years and interpreted our findings relative to the phylogeny of this group. We identified several interspecific polymorphisms in glucosinolate composition. A majority of these polymorphisms are lineage-specific secondary losses of glucosinolate characters, but a gain-of-character polymorphism was also detected. The genetic basis of most observed polymorphisms appears to be regulatory. In the case of A. lyrata, geographic distribution is also shown to contribute to glucosinolate metabolic diversity. Further, we observed evidence of gene-flow between sympatric species, parallel evolution, and the existence of genetic constraints on the evolution of glucosinolates within the Brassicaceae.