In vitro and in silico analysis of two genes (A2-1 and G1-1) differentially regulated during dormancy and sprouting in potato tubers

Summary Two cDNAs, corresponding to genes differentially regulated during dormancy and sprouting in potato tubers, cultivar Désirée, were isolated: i) G1-1 corresponded to a gene that was turned off during dormancy and turned on during early phases of sprouting; ii) A2-1 corresponded to a gene activated during dormancy and strongly repressed during the transition from dormancy to sprouting. When induced, both genes were expressed at low level. Full-length cDNAs and genomic clones were isolated and characterized. G1-1 was a short gene, 452 bp long, containing an intronless open reading frame, coding for a putative protein of 64 aminoacids. Sequence analysis showed that G1-1 was homologous to an expressed sequence tag (EST) ofArabidopsis thaliana. A2-1 full-length cDNA was 1577 bp long and contained an open reading frame coding for a putative protein of 383 aminoacids, which contained a Walker box binding domain, common to a multifunctional family of intracellular ATPases.     

Silencing of G1-1 and A2-1 genes. Effects on general plant phenotype and on tuber dormancy inSolanum tuberosum L.

Summary We have evaluated the effect that the, silencing of two genes specifically expressed in conditions of dormancy (A2-1) and sprouting (G1-1) had on tuber dormancy. For this purpose potato plants (Solanum tuberosum L. cv. Désirée) were transformed with the antisense of the genes G1-1 and A2-1 under the control of constitutive 35S CaMV promoter. A first generation of transgenic plants was propagated from axenic stem cuttings and a second generation by tuber planting. The plants obtined were analyzed for the length of dormancy, plant morphology and agronomic characteristics. Statistical analysis of dormancy in lines obtained from the original transformants for the antisense of G1-1 gene showed a significant increase in length as compared with different types of control plants, with few effects on plant vegetative habit and tuber production. In contrast, results obtained on A2-1 antisense transformed plants did not reveal any significant change on the length of dormancy. Here we report small-scale field trials performed with the aim to select and regenerate commercially exploitable potato plants with a stable transgene-dependent phenotype, affecting the length of dormancy.     

Antibiotic Resistance in Salmonella Isolated from Tegus (Tupinambis spp.)

In recent years, an increase in human clinical cases of reptile-associated salmonellosis has been identified, and it has been attributed to the increased popularity of these animals as pets. Limited information is available regarding the distribution of Salmonella spp. serotypes in different reptile species and the antimicrobial resistance patterns of Salmonella spp. isolated from pet reptiles. This article describes the prevalence of Salmonella spp., distribution of serotypes, and antibiotic susceptibility patterns from isolates cultured from cloacal swabs obtained from 14 tegu lizards (Tupinambis spp.). Eighteen strains of Salmonella belonging to different serotypes were obtained from the 14 tegu lizards. Of the 18 Salmonella spp. isolates, 8 (44.4%) were from Salmonella subspecies I, with a majority of isolates belonging to the Eastbourne serotype (3 strains), Nottingham serotype (2 strains), and Brancaster serotype (2 strains), and only 1 belonging to the Apapa serotype. Less common serotypes were detected in 5 isolates, including 2 each belonging to Salmonella subspecies II and IIIb, respectively, and 1 to Salmonella subspecies IIIa. The serotype of 5 other Salmonella isolates could not be determined. All 18 isolates were resistant to at least 6 of the antimicrobial drugs tested. These results confirm the potential zoonotic risk from handling reptiles, suggesting that measures to educate the reptile-owning public are necessary.     

Robust and sensitive monoclonal enzyme-linked immunosorbent assay for the herbicide molinate

This paper reports on the generation of monoclonal antibodies and the development of a new enzyme-linked immunosorbent assay (ELISA) for the detection of molinate (S-ethyl hexahydroazepine-1-carbothioate). Hybridoma cells were generated using spleen and lymph node cells from a mouse immunized with S-2-carboxyethyl hexahydroazepine-1-carbothioate conjugated to keyhole limpet hemocyanin. After screening with a competitive ELISA, two monoclonal antibodies, mAbs 16C11 and 14D7, with IC(50) values of 82 +/- 2 and 173 +/- 8 ng/mL, respectively, were selected. MAb 16C11 can detect molinate concentrations of 1 ng/mL with no cross-reactivity to any other thiocarbamate pesticides; however, it was susceptible to the presence of organic solvents and to variation in buffer ionic strength. MAb 14D7 tolerated concentrations up to 5% of propylene glycol and 12.5% of acetonitrile in the assay buffer. The sensitivity of mAb 14D7 was further improved by decreasing the amount of coating antigen in the ELISA; the final inhibition assay showed an IC(50) of 69.2 +/- 1.4 ng/mL. In summary, mAb14D7 provided a more sensitive and robust assay, as compared with previous polyclonal antibody-based assays, with the additional advantage of being based upon a consistent and unlimited source of a defined reagent.     

Assessment of genetic diversity in emmer (Triticum dicoccon Schrank) × durum wheat (Triticum durum Desf.) derived lines and their parents using mapped and unmapped molecular markers

In the last few years, the renewed interest for emmer wheat (Triticum dicoccon Schrank) in Italy has stimulated breeding programs for this crop releasing improved genotypes obtained not only by selection from landraces, but even by crosses with durum wheat (Triticum durum Desf.) varieties. The purpose of this work has been to uncover the genetic make-up of some emmer × durum derivatives, specifically by comparing the differences from their parents. Genetic diversity of advanced breeding lines and varieties derived from a durum × emmer cross has been evaluated on the basis of AFLP and SSR markers in comparison with the corresponding emmer and durum wheat parent for addressing the seminal question of how much ‘wild’ variation remains after selection for agronomic type.     

Reducing the incidence of cereal head infection and mycotoxins in small grain cereal species

Reducing the level of infection of cereal heads caused by Fusarium and associated mycotoxin accumulation in grains is of a high priority in order to secure the yield, agronomic performance, and food and feed safety from field to table. Strategies to tackle the problem have been proposed at many levels, including greater knowledge of the biology of toxigenic fungi and of plant–pathogen interactions, monitoring activities which extend from the field to the end-products, pre-breeding, breeding and transgenesis to develop new resistant plant varieties, crop protection based on synthetic or natural molecules, biocontrol of fungal populations, the development and use of models that take into account the climatic conditions, and the adoption of technological protocols for reducing or inactivating mycotoxins. This review article highlights that the problem is very complex but that the scientific community continues to produce important knowledge and potential solutions.     

Access to land,livestock production and ecosystem conservation in the Brazilian Campos biome: The natural grasslands dilemma

How to improve access to land and livestock production in synergy with ecosystem conservation? The paradigm occurring in natural grasslands of the Southern Brazilian Campos biome is used to illustrate the dilemma. This paper aims to contribute by addressing the technical bases being used by legislations concerning access to land and incentive to production and their consequences for natural grassland systems. Current policies have a production-oriented focus trying to promote livestock productivity by setting minimum stocking rates to be applied in grasslands. The unexpected results are overgrazing and reduction of natural grasslands, so the dilemma production versus conservation emerges. There is a need for adapting access to land legislations to the new environmental functions expected for natural grasslands, which warrant a conservation-oriented approach according to their multifunctional role. Integrated measures are proposed, which could be helpful in resolving the conflicting compromises regarding the inducement of production and the promotion of natural resources conservation.