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The spatial distribution of species and their clades reflects the interaction of different ecological, evolutionary and stochastic processes that shape the current biogeographic patterns of biodiversity. Spatial patterns of alpha and beta phylodiversity can capture different historical processes such as niche conservatism, dispersal, diversification, and extinction, which may have operated over several million years. Eudemeae (Cruciferae) represents a clade of 43 species and 11 genera distributed throughout western South America, from the Northern Andes in Colombia (c. 5°N) to the southernmost portion of the Southern Andes in Argentina and Chile (c. 55°S). In this study, we attempt to elucidate the association between climate and phylodiversity variation in Eudemeae using distributional, climatic and molecular data for a large sample of taxa. Our study showed that beta phylodiversity patterns in Eudemeae are partially explained by climate, with climate tolerance being one of the main factors associated with variation in phylogenetic turnover. In particular, thermal tolerance is associated with turnover of deeper nodes, while aridity tolerance is related to turnover of more recent nodes. Likewise, temperature gradient appears to be associated with higher alpha diversity along the temperate regions of Central and Southern Andes, displaying the tribe an inverse latitudinal gradient in species diversity consistent with the austral niche conservatism hypothesis. In addition, major evolutionary regions showed high levels of climatic/ecological differentiation, and diversity hotspots showed phylogenetic clustering, suggesting that phylogenetic niche conservatism and in situ lineage diversification were dominant processes in the evolution of the tribe. [ABSTRACT FROM AUTHOR]

The diamondback moth, Plutella xylostella (Linnaeus) (Lepidoptera: Plutellidae), is a global pest of crucifer crops, mainly controlled with insecticides. However, this moth has shown populations from different geographical regions that are resistant to various synthetic insecticides, including organophosphates, pyrethroids, new molecules, and microbial-derived pesticides owing to repeated applications of these insecticides. This review is an effort to explore reported cases of insecticide resistance and mechanisms involved in P. xylostella throughout the world. It also includes a comprehensive overview of the mode of inheritance and fitness costs associated with the resistance of P. xylostella to different insecticides. Data from 20 research papers about field and laboratory resistance to various organochlorines and pyrethroids, and 54 papers on resistance to new chemical and microbial insecticides, showed the varying resistance levels in P. xylostella from different parts of the world. Cross-resistance results were also presented in 17 published papers. Moreover, the collected data of 25 research publications about resistance inheritance to various insecticides revealed that 84% of the published papers confirmed autosomal resistance, while sex-linked inheritance was confirmed in only 16% of the published literature. An association of high fitness costs with disadvantageous biological characteristics was evident from the summarized data of eight different studies. Studies about resistance mechanisms were presented in 32 published papers which depicted that metabolic resistance was prevalent over target sites. This effort will contribute to developing an effective management program to mitigate the resistance of P. xylostella to the main pest control strategies. [ABSTRACT FROM AUTHOR]

Xanthomonas campestris pv. campestris (Xcc) is a seedborne bacterium that causes black rot of crucifers. A real-time PCR assay based on a dual-labeled hydrolysis TaqMan® probe has been developed for the rapid and sensitive detection of Xcc and related pathovars that affect mainly Brassicaceae crops and ornamentals. Primers were designed to specifically amplify a 152 bp fragment of the Zur gene from X. campestris. To confirm the specificity of the detection, primers targeting the Zur and hrpF genes were used for standard and real-time PCR with DNA samples from 13 Xcc strains, seven Xanthomonas species and pathovars and five different bacterial endophytes including Bacillus, Erwinia, Klebsiella, Pantoea and Pseudomonas, previously isolated from tissues of crucifers. PCR products amplified with Zur and hrpF primers were sequenced to assess the genetic diversity of these genes in the tested isolates. The real-time PCR protocol was optimized to allow the detection at the level of ten copies of Zur PCR fragment per one microliter of DNA. Although the real-time based on detection of Zur also detected X. campestris pvs raphani, armoraciae, incanae and a strain of X. hortorum pv. carotae, it improved the specificity in relation to the previously published hrpF based real-time method. A multiplex assay for Zur and hrpF genes further improved the specificity by excluding X. hortorum pv. carotae. Tests of brassica tissues and seeds artificially inoculated with Xcc showed that the real-time PCR based on detection of Zur is an efficient and robust assay. [ABSTRACT FROM AUTHOR]

Brassica vegetables, which include broccoli, kale, cauliflower, and Brussel sprouts, are known for their high glucosinolate content. Glucosinolates and their derived forms namely isothiocyanates are of special interest in the pharmaceutical and food industries due to their antimicrobial, neuroprotective, and anticarcinogenic properties. These compounds are water soluble and heat-sensitive and have been proved to be heavily lost during thermal processing. In addition, previous studies suggested that novel non-thermal technologies such as high pressure processing, pulsed electric fields, or ultraviolet irradiation can affect the glucosinolate content of cruciferous vegetables. The objective of this paper was to review current knowledge about the effects of both thermal and non-thermal processing technologies on the content of glucosinolates and their derived forms in brassica vegetables. This paper also highlights the importance of the incorporation of brassica vegetables into our diet for their health-promoting properties beyond their anticarcinogenic activities. [ABSTRACT FROM AUTHOR]

Alternaria species are common pathogens of fruit and vegetables able to produce secondary metabolites potentially affecting human health. Twenty-nine isolates obtained from cabbage, cauliflower, wild and cultivated rocket were characterized and identified based on sporulation pattern and virulence; the phylogenetic analysis was based on the β-tubulin gene. Isolates were identified as A. alternata, A. tenuissima, A. arborescens, A. brassicicola and A. japonica. Pathogenicity was evaluated on plants under greenhouse conditions. Two isolates showed low level of virulence on cultivated rocket while the other isolates showed medium or high level of virulence. Isolates were also characterized for their mycotoxin production on a modified Czapek-Dox medium. Production of the five Alternaria toxins, tenuazonic acid, alternariol, alternariol monomethyl ether, altenuene and tentoxin were evaluated. Under these conditions, about 80% of the isolates showed the ability to produce at least one mycotoxin. [ABSTRACT FROM AUTHOR]

The effect of cruciferous plant residues (milled seeds of mustard and rapeseed meals) on the colonization of onion (Allium cepa L.) seedling roots by Pantoea ananatis was investigated. These materials incorporated into a peat medium at a dosage of 0.5% (w/v) decreased the colonization of onion seedlings by the pathogenic bacterium. These materials showed also a positive effect on the growth of onion seedlings, increasing fresh plant weight by three to fivefolds. Moreover, the total microorganism population was higher in the peat medium additioned with plant materials than in the control. An increase in the total number of bacteria and actinomycetes was observed, which may have caused a higher suppressiveness of the peat medium towards P. ananatis. On the other hand, the biological active compounds released from crucifers may have inhibited the growth of the bacterium. [ABSTRACT FROM AUTHOR]

Northern Iran has one of the largest and most diverse populations of cultivated crucifers in Iran. Symptoms of black rot disease were observed in 40 % of fields. To assess the genetic diversity of Xanthomonas campestris pv. campestris ( Xcc) strains, associated with black rot disease, 40 strains were isolated from infected samples of crucifers such as cabbage, radish, cauliflower, turnip and kohlrabi, and were collected from different geographic regions of northern Iran including West and East Azarbayjan and Ardabil provinces. Bacterial strains were characterized by their morphological, biochemical and physiological features and pathogenicity tests. Four races were found in northern Iran (1, 4, 5 and 6) and the majority of the tested strains belonged to either race 4 (45 %) or race 6 (20 %). To examine the distribution of dispersed repetitive DNA, Enterobacterial Repetitive Intergenic Consensus (ERIC), BOX, Repetitive Extragenic Palindromic (REP) and random amplified polymorphic DNA (RAPD) sequences in the genome of Xcc using conserved primers. The different markers produced characteristic banding patterns and the similarity matrices from binary banding data was derived with the similarity for qualitative data program (SIMQUAL). On the basis of the fingerprint patterns generated by the combination data set of both rep-PCR and RAPD, the Xcc strains were differentiated into seven clusters (A-G) at 76 % similarity level. The geographical origin of the Iranian strains does not seem to be correlated with the RAPD and rep-PCR clusters. The clusters seem to be more related to the race of the strains. This is the first study on genetic diversity of Xcc strains inducing black rot disease of crucifers in Iran. [ABSTRACT FROM AUTHOR]

Fifty-six native isolates collected in 12 farming districts of Trinidad and seven reference strains of Xanthomonas campestris pv. campestris were evaluated for resistance to copper in buffered (pH 7.0) and unbuffered (pH 5.6) nutrient agar media. All isolates and reference strains were pathogenic and elicited typical black rot symptoms on a susceptible variety of Brassica olearceae, 'Copenhagen Market'. Thirty-four and thirty-three native isolates were highly resistant to copper (growth on ≥ 200 ppm copper) in buffered and unbuffered media, respectively; however, all the reference strains were highly susceptible to copper. The mean minimum inhibition concentration for the 56 native isolates was 224.6 ppm copper indicating that high levels of copper resistance are present in X. campestris pv. campestris in Trinidad. The association between growth of the 56 isolates and seven reference stains on buffered and unbuffered media was strong (Pearson's and Spearman's r = 0.93; P < 0.01) suggesting that either medium can be used to evaluate resistance to copper in X. campestris pv. campestris. There was also a strong association between length of time of continuous applications of copper formulations to treat black rot disease and proportion of the native X. campestris pv. campestris with resistance to copper (Pearson's r = 0.96; Spearman's r = 0.93); however, there was no association between resistance to copper and aggressiveness at 10 days after inoculation. [ABSTRACT FROM AUTHOR]

Cauliflower ( Brassica oleracea L. var. botrytis) and mustard [ Brassica juncea (L.) Czern] are important cruciferous crops facing serious yield and quality loss in India from dark leaf spot disease caused by Alternaria brassicae (Berk.) Sacc. Genetic variation among 32 pathogenic A. brassicae isolates from both crops was analyzed with random amplified polymorphic DNA and inter-simple sequence repeat primers in which the mean similarity coefficient was found to be 0.73 and 0.84, respectively. Further internal transcribed spacer analysis showed all isolates are 90-100 % similar to each other, indicating genetic similarity among different A. brassicae isolates that vary pathogenically. [ABSTRACT FROM AUTHOR]

Raphanus sativus, a common cruciferous vegetable has been attributed to possess a number of pharmacological and therapeutic properties. It has been used in indigenous system of medicine for the treatment of various human ailments in India. This present study evaluated the chemopreventive efficacy of different parts of R. sativus such as root, stem and leaves, extracted with solvents of varying polarity and investigated the molecular mechanism leading to growth arrest and apoptotic cell death in human cancer cell lines. Of the different parts, significant growth inhibitory effect was observed with hexane extract of R. sativus root. Analysis of hexane extract by GC-MS revealed the presence of several isothiocyanates (ITCs) such as 4-(methylthio)-3-butenyl isothiocyanate (MTBITC), 4-(methylthio)-3-butyl isothiocyanate (erucin), 4-methylpentyl isothiocyanate, 4-pentenyl isothiocyanate and sulforaphene. R. sativus root extract induced cell death both in p53 proficient and p53 deficient cell lines through induction of apoptotic signaling pathway regardless of the p53 status of cells. The molecular mechanisms underlying R. sativus-induced apoptosis may involve interactions among Bcl family genes, as evidenced by up-regulation of pro-apoptotic genes and down-regulation of anti-apoptotic genes along with activation of Caspase-3. Our findings present the first evidence that hexane extract of R. sativus root exerts potential chemopreventive efficacy and induces apoptosis in cancer cell lines through modulation of genes involved in apoptotic signaling pathway. [ABSTRACT FROM AUTHOR]

Clubroot, caused by Plasmodiophora brassicae, is one of the most important diseases of brassicas. Management of clubroot is difficult, and the best means of avoiding the disease include planting in areas where P. brassicae is not present and using plants and growing media free from pathogen inoculum. As P. brassicae is not culturable, its detection has traditionally relied on plant bioassays, which are time-consuming and require large amounts of glasshouse space. More recently, fluorescence microscopy, serology, and DNA-based methods have all been used to test soil, water, or plant samples for clubroot. The use of fluorescence microscopy to detect and count pathogen spores in the soil requires significant operator skill and is unlikely to serve as the basis for a routine diagnostic test. By contrast, serologic assays are inexpensive and amenable to high-throughput screening but need to be based on monoclonal antibodies because polyclonal antisera cannot be reproduced and are therefore of limited quantity. Several polymerase chain reaction (PCR)-based assays have also been developed; these are highly specific for P. brassicae and have been well-correlated with disease severity. As such, PCR-based diagnostic tests have been adopted to varying extents in Canada and Australia, but wide implementation has been restricted by sample processing costs. Efforts are underway to develop inexpensive serologic on-farm diagnostic kits and to improve quantification of pathogen inoculum levels through real-time PCR. Proper detection and quantification of P. brassicae will likely play an increasingly important role in the development of effective clubroot management strategies. [ABSTRACT FROM AUTHOR]

Transgenic pakchoi ( Brassica rapa L. ssp. chinensis) plants were obtained in the progeny of plants infiltrated by an Agrobacterium tumefaciens strain carrying a gene for resistance to the herbicide phosphinotricin (Basta). Genetic analysis demonstrates the transmission of the herbicide resistant trait to the progeny. Molecular analyses show that the transgene was inserted in the plant genome and expressed. This work demonstrates that the infiltration transformation method originally devised for Arabidopsis thaliana can be adapted for other crucifer species and opens up the possibility of genetic engineering of pakchoi, an important vegetable plant. [ABSTRACT FROM AUTHOR]

A series of RAPD markers generated by a single 10-mer primer were analyzed by hybridization to amplified and genomic DNA and by sequencing in two Brassica species. Primer B18 produced different profiles of nine major bands each in both Brassica nigra (B genome) and B. napus (AC genomes). Cloning and sequencing of five B18 B. nigra amplification products revealed that they were all unrelated to each other. Only limited stretches of high similarity of up to 69 nucleotides were shared by some of these clones. Hybridization to genomic DNA indicated that only two corresponded to a highly repeated sequence, whereas the rest were low copy sequences. In spite of their lack of homology, when these clones were used as probes to amplified B. nigra DNA, they hybridized to multiple bands in the profile. Hybridization of B. nigra clones for bands of similar sizes in both species, failed to hybridize in B. napus, revealing lack of homology between the DNAs of the two species. Because of these inconsistencies, it is concluded that RAPD markers, although useful for genetical studies, should be used with caution specially when basing homology on cross-hybridization and fragment sizes. [ABSTRACT FROM AUTHOR]

The glucosinolate content of the 3 host plants, viz. yellow sarson, Brassica campestris L. var. yellow sarson, Chinese cabbage, Brassica campestris L. var. pekinensis and taramira, Eruca sativa Lam. var. ITSA differed qualitatively as well as quantitatively mainly with respect to allyl-, methylthiobutyl-, pent-4-enyl-, methyl- and benzyl-glucosinolates. The mean number of total probes on feeding media incorporated with crude extracts containing glucosinolates from 0·25, 0·50 and 1·0 g green parts of taramira per ml of feeding media was 5·8, 6·7 and 8·4, respectively. Such probes in case of yellow sarson and Chinese cabbage were 2·6, 2·2 and 1·5; and 2·6, 2·0 and 3·0, respectively. The mean number of probes on feeding media containing sinigrin (K-allylglucosinolate) at the rate of 0·125, 0·25, 0·50 and 1·0% was 1·9, 3·3, 3·9 and 5·2, respectively. Uptake of feeding media incorporated with extracts containing glucosinolates from taramira, yellow sarson and Chinese cabbage varied from 4·05-9·40, 31·5-52·0 and 30·5-51·3%, respectively. Similarly, the uptake in the case of feeding media containing sinigrin (0·125-1%) varied from 1·6-44·95%). [ABSTRACT FROM AUTHOR]

By manipulating plant variety and predator species, we investigated the interactions of plant and predator traits in determining predation effectiveness. The predators were all coccinellid adults ( Hippodamia convergens, Hippodamia variegata, Coccinella apunctata, and Coccinella septempunctata) and the prey were cabbage aphids ( Brevicoryne brassicae). Foraging behavior of the four predators was observed on four crucifers that differed widely in their structures and surface textures ( Brassica oleracea caulorapa, Brassica campestris, Brassica juncea crispifolia, and Hirschfeldia incana). Predation rates were significantly influenced by plant variety, a result we attribute to direct effects of plant morphology on predator mobility, falling frequency, and prey accessibility. Predation rates did not vary significantly among the ladybirds, although the four species did exhibit distinct foraging strategies as measured by time spent actively foraging, the rate of encountering aphids, and the fraction of aphids encountered that were consumed. The coccinellids also differed in their propensity for flying away from the plant, and in the frequency with which they fell from the plant. We did not detect any significant interaction effects between plant and predator species, suggesting that the main effects of plant and predator species may overwhelm their interactions in this kind of system. Our results suggest that the level of predation upon herbivorous insects may depend more upon plant architecture than on the particular species of natural enemies present. [ABSTRACT FROM AUTHOR]

Plants that are infested by herbivores emit volatile cues that can be used by the natural enemies of the herbivores in their search for hosts. Based on results from behavioral studies, we investigated to what extent intact and herbivore-infested plant species and varieties from the food plant range of Pieris herbivore species differ in the composition of the volatile blends. Parasitoids of Pieris species, Cotesia glomerata and C. rubecula, show differential responses towards various herbivore-infested food plants, whereas differences in responses to plants infested by other herbivore species were less clear. Chemical analysis of the headspace samples of red cabbage, white cabbage, and nasturtium plants that were infested by P. brassicae or P. rapae larvae, or that were intact, yielded 88 compounds including alcohols, ketones, aldehydes, esters, nitriles, terpenoids, sulfides, (iso)thiocyanates, carboxylic acids, and others. The analysis revealed that herbivore-infested plants emit the largest number of compounds in the highest amounts. The plant species affected the volatile blend more than did the herbivore species, and differences between plant varieties were less pronounced than differences between plant species. Differences in headspace composition between plants infested by P. brassicae or P. rapae were mainly of a quantitative nature. Herbivore-infested nasturtium differed considerably from the cabbage varieties in a qualitative way. Headspace compositions of red and white cabbage varieties were comparable to that of the food plant Brussels sprouts ( Brassica oleracea gemmifera cv. Titurel) as determined in earlier studies in our laboratory. With respect to plant response to herbivory, nasturtium differed considerably from the cabbage varieties analyzed so far and shows resemblance with Lima bean, cucumber, and corn. These plant species produce a greater quantity and variety of volatiles under herbivore attack than intact plants. The results of this study are discussed in relation to behavioral observations on C. glomerata and C. rubecula. [ABSTRACT FROM AUTHOR]

The carbon/nutrient balance hypothesis has recently been interpreted to predict that plants grown under elevated CO2 environments will allocate excess carbon to defense, resulting in an increase in carbon-based secondary compounds. A related prediction is that, because plant growth will be increasingly nitrogen-limited under elevated CO2 environments, plants will allocate less nitrogen to defense, resulting in decreased levels of nitrogen-containing secondary compounds. We present the first evidence of decreased investment in nitrogen-containing secondary compounds for a plant grown under elevated CO2. We also present evidence that plant response is species-specific and is not correlated with changes in leaf nitrogen content or leaf carbon–nitrogen ratio. When three crucifers were grown at 724 ± 8 ppm CO2, total foliar glucosinolate content decreased significantly for mustard, but not for radish or turnip. Glucosinolate content of the second and fourth youngest mustard leaves decreased by 45% and 31%, respectively. In contrast, no significant change in total glucosinolate content was observed in turnip or radish leaves, despite significant decreases in leaf nitrogen content. Total glucosinolate content differed significantly among leaves of different age; however, the trend differed among species. For both mustard and turnip, glucosinolate content was significantly higher in older leaves, while the opposite was true for radish. No significant CO2 × leaf age interaction was observed, suggesting that intraplant patterns of allocation to defense will not change for these species. Changes in nitrogen allocation strategy are likely to be species-specific as plants experience increasing atmospheric CO2 levels. The ecological consequences of CO2-induced changes in plant defensive investment remain to be investigated. [ABSTRACT FROM AUTHOR]

EcoRI restriction of the B. nigra rDNA recombinants, isolated from a lambda genomic library, showed that the 3.9-kb fragment corresponded to the Intergenic Spacer (IGS), which was sequenced and found to be 3,928 by in size. Sequence and dot-matrix analyses showed that the organization of the B. nigra rDNA IGS was typical of most rDNA spacers, consisting of a central repetitive region and flanking unique sequences on either side. The repetitive region was composed of two repeat families-RF 'A' and RF 'B.' The B. nigra RF 'A' consisted of a tandem array of three full-length copies of a 106-bp sequence element. RF 'B' was composed of 66 tandemly repeated elements. Each 'B' element was only 21-bp in size and this is the smallest repeat unit identified in plant rDNA to date. The putative transcription initiation site (TIS) was identified as nucleotide position 3,110. Based on the sequence analysis it was suggested that the present organization of the repeat families was generated by successive cycles of deletions and amplifications and was being maintained by homogenization processes such as gene conversion and crossing-over. A detailed comparison of the rDNA IGS sequences of the three diploid Brassica species-namely, B. nigra, B. campestris, and B. oleracea-was carried out. First, comparisons revealed that B. campestris and B. oleracea were close to each other as the repeat families in both showed high sequence homology between each other. Second, the repeat elements in both the species were organized in an interspersed manner. Third, a 52-bp sequence, present just downstream of the repeats in B. campestris, was found to be identical to the B. oleracea repeats, thereby suggesting a common progenitor. On the other hand, in B. nigra no interspersion pattern of organization of repeats was observed. Further, the B. nigra RF 'A' was identified as distinct from the repeat families of B. campestris and B. oleracea. Based on this analysis, it was suggested that during speciation B. campestris and B. oleracea evolved in one lineage whereas B. nigra diverged into a separate lineage. The comparative analysis of the IGS helped in identifying not only conserved ancestral sequence motifs of possible functional significance such as promoters and enhancers, but also sequences which showed variation between the three diploid species and were therefore identified as species-specific sequences. [ABSTRACT FROM AUTHOR]

Using primarily cDNA restriction fragment length polymorphism markers (RFLPs) previously located to Brassica oleracea (cabbage, 2n=18) chromosomes, we initiated a comparative RFLP map in an F population of B. campestris (turnip x mock pak-choi, 2n=20). As with B. oleracea, the genome of B. campestris showed extensive gene duplication, and the majority of detected duplicated loci were unlinked. Only 6 of the 49 identified loci were represented as a single copy, and 3 of these 6 were clustered on a single linkage group showing a distorted segregation ratio. Comparison with B. Oleracea indicates this synteny is conserved between species. Two other linkage groups also appeared syntenic between B. oleracea and B. campestris. One single copy locus appears to have changed synteny between B. oleracea and B. campestris. These observations suggest that B. oleracea and B. campestris share a common ancestor, but that chromosome repatterning has occurred during or after speciation. Within B. campestris, 5 loci appeared duplicated in one parent or the other, and 2 of these were linked. Differentiation through subspecies-specific duplication or deletion events is suggested as one mechansim for the evolution of numerous morphotypes within each of these species. [ABSTRACT FROM AUTHOR]

The effect of short-term high temperature on the expression of self-incompatibility was studied in detached flowers of Brassica oleracea, B. campestris and Raphanus sativus. The expression of self-incompatibility was repressed by treatment of pistils at 40 °C for 15 minutes. Treatment at 50 °C repressed self-incompatibility but it also disturbed pollen tube elongation into stylar tissue. S-glycoproteins did not show any quantitative changes during the intact pistil treatment under 50 °C. Callose was occasionally found in the treated papilla where the self pollen tube penetrated. The repressing effect of the 40 °C treatment was found to be reversible, and this reversibility depended upon the environmental temperature of plant. Plants grown at 15/5 °C (day/night temperature) completely recovered self-incompatibility 2 h after treatment, while those grown at 20/10°, 25/15 °C did not. The reversibility of the expression of self-incompatibility correlated with the distortion of plasma membrane in the papilla. It is considered that high temperature affects the pollen tube penetration system in pistils rather than the recognition system between pistils and pollen. The treatment of dehiscing anthers at 40 °C killed the pollen. [ABSTRACT FROM AUTHOR]

Twenty strains of Xanthomonas campestris pv. campestris (Xcc) were isolated from two major crucifer-growing valleys, Chitwan and Kathmandu in Nepal and characterized by biochemical and pathogenicity tests. Strains were homogeneous in bacteriological characteristics. The ability of a strain to induce high or low disease severity index (DSI) on three host plants, broccoli, cabbage, and cauliflower, was interpreted as virulence. Strains that were associated with high or low virulence were significantly different (P>0.05). No relationship between virulence and biochemical characteristics was observed. [ABSTRACT FROM AUTHOR]