Project description:Plants reorganize their root architecture to avoid growth into unfavorable regions of the rhizosphere. In a screen based on chimeric repressor gene-silencing technology, we identified the Arabidopsis thaliana GeBP-LIKE 4 (GPL4) transcription factor as an inhibitor of root growth that is induced rapidly in root tips in response to cadmium (Cd). We tested the hypothesis that GPL4 functions in the root avoidance of Cd by analyzing root proliferation in split medium, in which only half of the medium contained toxic concentrations of Cd. The wild-type (WT) plants exhibited root avoidance by inhibiting root growth in the Cd side but increasing root biomass in the control side. By contrast, GPL4-suppression lines exhibited nearly comparable root growth in the Cd and control sides and accumulated more Cd in the shoots than did the WT. GPL4 suppression also altered the root avoidance of toxic concentrations of other essential metals, modulated the expression of many genes related to oxidative stress, and consistently decreased reactive oxygen species concentrations. We suggest that GPL4 inhibits the growth of roots exposed to toxic metals by modulating reactive oxygen species concentrations, thereby allowing roots to colonize noncontaminated regions of the rhizosphere.thereby re-allocating root biomass toward non-contaminated rhizosphere areas and minimizing root exposure to toxic metals.
Project description:The pyrite mine of Lousal, Grândola, Portugal, was discovered in 1882 and extensively exploited from 1900 until its closure in 1988 when the mining ores were not viable economically. Aiming at becoming a cultural-touristic center, the mining area was rehabilitated raising a Mining Museum and a Science Centre along with the reopening of a mining gallery for public access. In recent times, aerobiological studies on subterranean environments such as caves, mines and archeological necropolis revealed to be an important source of novel bacteria, from which their biotechnological potential are under study. Here we present a Pseudomonas sp. isolated from the mine air with potential secondary metabolite biosynthesis, resistance to antibiotics and virulence factors.
Project description:A DNA microarray analysis detected large-scale changes of gene expression in response to Cd stress with a substantial difference between the two barley genotypes differing in Cd tolerance and accumulation. Cd stress led to higher expression of genes involved in transport, carbohydrate metabolism and signal transduction in the low-grain-Cd-accumulating genotype. Novel transporter genes such as zinc transporter genes were identified as being associated with low Cd accumulation. We used microarrays to understand the mechanism of low Cd accumulation in crops which is crucial for sustainable safe food production in Cd-contaminated soils.
Project description:Cadmium (Cd) is a highly toxic and carcinogenic pollutant that poses a threat to human and animal health by affecting several major organ systems. Urbanization and human activities have led to significant increases in Cd concentration in the environment, including in agroecosystems. To protect against the harmful effects of Cd, efforts are being made to promote safe crop production and to clean up Cd-contaminated agricultural lands and water, reducing Cd exposure through the consumption of contaminated agricultural products. There is a need for management strategies that can improve plant Cd tolerance and reduce Cd accumulation in crop plant tissues, all of which involve understanding the impacts of Cd on plant physiology and metabolism. Grafting, a longstanding plant propagation technique, has been shown to be a useful approach for studying the effects of Cd on plants, including insights into the signaling between organs and organ-specific modulation of plant performance under this form of environmental stress. In this review, we aim to highlight the current state of knowledge on the use of grafting to gain insights into Cd-induced effects as well as its potential applicability in safe crop production and phytoremediation. In particular, we emphasize the utility of heterograft systems for assessment of Cd accumulation, biochemical and molecular responses, and tolerance in crop and other plant species under Cd exposure, as well as potential intergenerational effects. We outline our perspectives and future directions for research in this area and the potential practical applicability of plant grafting, with attention to the most obvious gaps in knowledge. We aim at inspiring researchers to explore the potential of grafting for modulating Cd tolerance and accumulation and for understanding the mechanisms of Cd-induced responses in plants for both agricultural safety and phytoremediation purposes. Finally, it is important to bear in mind that although we have address Cd in this review, the idea can be applied to the large majority of abiotic and biotic stressors.