The subjects of this article are protoplast isolations and protoplast fusions, in particular their history, a review of factors influencing the protoplasts isolation and fusion, selection of hybrid plants and utilization of somatic hybrids in plant breed-ing. Somatic hybridization through protoplast fusion can overcome sexual incompatibility among plant species or genera; transfer genes of resistance to diseases (viral, bacterial, fungal), pests, herbicides and others stress factors; obtain cybrid plants; transfer cytoplasmic male sterility or incease content of secondary metabolites in hybrid plants. The article is focussed mainly on the family Brassicaceae because among representatives are significant crops for the human population. Various successful combination of intraspecific, interspecific and intergeneric protoplast fusion were reported between representatives of the family Brassicaceae with the genus Brassica which belonged to the first agricultural crops used for the isolation of protoplast.

Plutella xylostella (L). Lepidoptera Plutellidae is the principal pest of Brassicaceae in Benin. Plutella populations from different localities in Benin exhibited differences in biological behaviour. The number of eggs per female and length of oviposition period differed significantly between some populations. (Résumé d'auteur)

Over the last decade glucosinolates contained in different tissues of Brassicaceae and their breakdown products, especially isothiocyanates formed after myrosinase-catalyzed hydrolysis, have been considered not only important antitumoral compounds but also as interesting “biopesticides” for controlling soil borne pathogens. This is the reason why the identification and the quantitative determination of each individual glucosinolate contentsin green tissues (leaves, roots, stem) are of great importance. The aim of this paper is to establish a joint protocol containing the guidelines to determine glucosinolate contents in fresh Brassicaceae tissues by HPLC of desulfo-glucosinolates. Some modifications of the ISO 9167-1 method, initially set up for evaluating rapeseed seeds, are proposed and discussed with the objective of optimizing and standardizing glucosinolate analysis in fresh tissues (leaves, roots or stems) of Brassicaceae. Collection, storage and preparation of fresh samples suitable to be analyzed are important steps during which it is necessary to avoid glucosinolate hydrolysis by the endogenous myrosinase-catalyzed reaction. The techniques of extraction and desulfatation of glucosinolates, the choice and purification of the internal standard, and the HPLC conditions (including the relative response factors) are also presented. The possibility of a convenient and simplified use of an alternative isocratic HPLC method for an accurate qualitative and quantitative determination of glucosinolates is also discussed and evaluated. The identification of desulfo-glucosinolates is performed by comparison of their retention times and UV spectra, and by GC-MS analysis of the compounds resulting from myrosinase-catalyzed hydrolysis of glucosinolates.The experience acquired in the field of the preparation of glucosinolate or desulfo-glucosinolate as chromatographic standards, using free and immobilized sulfatase is also presented.

Pollen morphology of 8 species of the genus Arabidopsis (Brassicaceae) from Pakistan hasbeen examined by light microscopy. Pollen grains are usually prolate to subprolate with 3-4colpate, syncolpate and reticulate tectum. However the species show variation in length ofcolpi and thickness of exine.

International audience | Ceutorhynchus assimilis has been selected as a potential biological control agent of Lepidium draba, which is a Eurasian invasive weed in North America. Preliminary studies indicated specificity of this weevil collected in southern France on L. draba. This result was in discord with the pest status of C. assimilis found in the literature. Host-specificity tests based both on field and laboratory experiments showed heterogeneity in the host spectrum of the weevils reared from different host-plants as determined by larval development. However, no distinguishable morphological differences could be visually detected between the populations feeding on different host-plants. All sampled populations of weevils were polyphagous as adults. Weevils reared from L. draba were specific to this plant for their complete larval development. Conversely, populations living on other wild and cultivated Brassicaceae species were not able to use L. draba as a host plant. Such differentiation is further highlighted by other biological aspects such as plant infestation rates, sex-ratio, duration of larval development, and differences in the timing of their life cycles. These results demonstrate that C. assimilis, an insect species formerly considered as a pest of Brassicaceae, is characterized by its host-range variability, with one population being potentially useful in the biological control of L. draba. Moreover, this example points to the need to test multiple populations of biological control agents in assessing risk.

A prototypical characteristic of the Brassicaceae is the presence of the myrosinase-glucosinolate system. Myrosinase, the only known S-glycosidase in plants, degrades glucosinolates, thereby initiating the formation of isothiocyanates, nitriles and other reactive products with biological activities. We have used myrosinase gene promoters from Brassica napus and Arabidopsis thaliana fused to the β-glucuronidase (GUS) reporter gene and introduced into Arabidopsis thaliana, Brassica napus and/or Nicotiana tabacum plants to compare and determine the cell types expressing the myrosinase genes and the GUS expression regulated by these promoters. The A. thaliana TGG1 promoter directs expression to guard cells and phloem myrosin cell idioblasts of transgenic A. thaliana plants. Expression from the same promoter construct in transgenic tobacco plants lacking the myrosinase enzyme system also directs expression to guard cells. The B. napus Myr1.Bn1 promoter directs a cell specific expression to idioblast myrosin cells of immature and mature seeds and myrosin cells of phloem of B. napus. In A. thaliana the B. napus promoter directs expression to guard cells similar to the expression pattern of TGG1. The Myr1.Bn1 signal peptide targets the gene product to the reticular myrosin grains of myrosin cells. Our results indicate that myrosinase gene promoters from Brassicaceae direct cell, organ and developmental specific expression in B. napus, A. thaliana and N. tabacum.

Identification and DNA polymorphism of the kinase domain of S-locus receptor kinase (SRK) which participates in the self-incompatibility of Brassicaceae were analyzed by polymerase chain reaction (PCR)-restriction fragment length polymorphism and nucleotide sequencing. In the PCR experiment, a SRK-specific primer pair (KS 5 and KA 7) of the class Ⅰ amplified a single DNA fragment of about 900 bp from 61 lines out of 134 inbred lines. Four groups were found in a double digestion with HintⅠ and EcoRⅡ using the class Ⅰ SRK-specific primer pairs.

Apomixis in model systems has been of growing interest for many scientists around the world. A limited number of species belonging to Brassicaceae has been described as apomictic and considered as a model system to study molecular biology of apomixis. In this study, we report the use of an ovule-clearing technique to characterize embryo sac development in Arabis gunnisoniana. The embryo sac development was detected by Taraxacum-type diplosporous dyad formation. Hence, the reproductive pathways in Arabis gunnisoniana were revealed by using flow cytometric seed screen (FCSS) analysis. Arabis gunnisoniana appears to display pseudogamous apomixis.

The root-knot nematode Meloidogyne incognita (Kofoid et White) Chitw. is responsible for large yield losses in several horticultural crops. Fumigation with chemicals has been efficient in fighting this soil pest, but it clearly shows a negative environmental impact. Thus, it is necessary to find an environmentally friendly alternative to control this nematode and meet the requirements imposed by world regulation to ban some chemical fumigants in the world after 2005. The glucosinolate-myrosinase system, typical of the Brassicaceae family, appears to be an important natural alternative for the control of several soilborne pests and pathogens. The aim of this study was to evaluate, in vitro, the biocidal activity of 11 glucosinolates and their degradation products on second-stage juveniles of the root-knot nematode M. incognita expressed by the nematicidal (LD50) and immobilization effects, after 24 and 48 h. None of the intact glucosinolates had any biological effect. After myrosinase addition, their hydrolysis products (essentially isothiocyanates) resulted in highly different biocidal activities. Among the hydrolysis products of the tested glucosinolates, 2-phenylethyl, benzyl, 4-methylthiobutyl, and prop-2-enyl isothiocyanate showed the stronger activity, with an LD50 at concentrations of 11, 15, 21, and 34 M, respectively. On the basis of the in vitro test results, new genotypes of Brassicaceae had been selected for high content in the roots of the glucosinolates generating the more active isothiocyanates and their agronomic performances verified in view of a full-field application as catch crop plants. With this aim, the qualitative and quantitative glucosinolate contents in the roots of these potentially nematicidal plants are also reported and discussed.

We used field-collected seeds of Arabidopsis thaliana (Brassicaceae) to simulate a colonization event of plants from diverse locations into a common environment to compare regionally "local" and "foreign" populations of this historically mobile species. Life history varied among regional groups, but most variation was found among populations within regions. While we found significant differences among populations and regional groups for important life-history characters, we did not find significant differences in performance of plants from different populations or regional groups. Rather, we found evidence that differences in life history contributed to the ability of plants from foreign regions to perform comparably to local Kentucky plants. Had plants from different regions not differed in the timing and size of reproduction, we would have seen that Kentucky (local) plants had higher total fitness via greater reproductive success of individuals that survived to reproduce and that Michigan plants would have had the lowest fitness. The populations are comparably adapted to the environment in Kentucky but through different combinations of life-history characters. Therefore, the life-history variation in this mobile species appears to contribute not to fitness differences among populations but rather to success in colonizing new locations.