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Abstract: Phyllostictine A is a powerful toxin produced by Phyllosticta cirsii, a potential mycoherbicide of Cirsium arvense. To support its potential use as a natural herbicide, toxin production has been studied using different media and cultural conditions. The toxin content in the crude extracts has been determined by using a HPLC method set up for this purpose. Furthermore, its phytotoxicity has been evaluated on tobacco protoplasts by flow cytometric analysis, and on C. arvense protoplasts, by fluorescence microscopy. The best cultural conditions found allowed to produce more than 28mgml−1 of toxin in culture filtrate. The pure metabolite proved to have rapid dose-dependant toxic effects on host and no-host plant protoplasts. [Copyright &y& Elsevier]

Abstract: Italian lentil landraces are principally cultivated for self or local consumption. Most of them are disappearing, particularly macrosperma types by being less required by the market. A pre-requisite for the conservation and the efficient use of genetic resources is the better understanding of the extent and the distribution of the existing genetic variation, useful for future breeding programmes. Our study was undertaken to analyse and quantify the genetic diversity within and among three macrosperma Italian lentil landraces (Onano, Altamura and Villalba), using fluorescent AFLP markers. AFLP markers generated information to differentiate among closely related genotypes and group within the same cluster individuals belonging to the same landrace. The total genetic diversity (H T), the genetic diversity within population (H S) and the extent of differentiation between populations (D ST) were 0.198, 0.155 and 0.043, respectively. The fixation index (G ST =0.219) showed that about 78% of the observed total genetic variation can be attributed to within population differences and around 22% is due to differences among populations. The gene flow estimate (N m =1.774) and the mean genetic distance value (0.077) suggested narrow genetic base among the analysed populations, confirming the tendency of Italian lentil landraces to group together. The present study showed that fluorescence-based AFLP technique is a biotechnological tool that can provide significant insights for research in genetic diversity of lentil landraces and their subsequent conservation and utilization in breeding programs. [Copyright &y& Elsevier]

One of the most important goals in the genetic improvement of lemon in the Mediterranean area is certainly the obtainment of new genotypes tolerant or resistant to mal secco disease. Two lemon cybrids (one diploid and one autotetraploid) with an intermediate degree of resistance to mal secco disease, spontaneously obtained by symmetric protoplast fusion between ‘Valencia’ orange and ‘Femminello’ lemon, were used as mother plants in backcrosses with a diploid clone of ‘Femminello’ lemon tolerant to the mal secco disease (LTMS) to improve tolerance and fruit quality. Since ‘Femminello’ lemon normally reproduces apomictically by nucellar embryony, an embryo-rescue technique was applied 105 days after pollination to recover zygotic embryos. Sixty-six plantlets were regenerated as follows: 20 from the 4nX2n cross and 46 from the 2nX2n cross. In order to distinguish zygotic embryos from nucellars, flow cytometry was applied on all the 66 plantlets; and a modified amplified fragment-length polymorphism (AFLP) technique and microsatellite analysis were carried out on a sample of 20 seedlings (six triploids and 14 diploids). Here, we report the usefulness and reliability of the tested techniques and discuss the results obtained. Flow cytometry (FCM) was useful only in inter-ploid crosses, identifying six triploids, four of which were also detected by simple sequence repeat (SSR) analysis and only two by modified AFLP. Among the 14 tested diploids, five zygotic genotypes were identified by SSR and four by modified AFLP. In our hands, the SSR technique appeared to be more suitable than modified AFLP. [Copyright &y& Elsevier]