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Background:The production of a new lateral root from parental root primary tissues has been investigated extensively, and the most important regulatory mechanisms are now well known. A first regulatory mechanism is based on the synthesis of small peptides which interact ectopically with membrane receptors to elicit a modulation of transcription factor target genes. A second mechanism involves a complex cross-talk between plant hormones. It is known that lateral roots are formed even in parental root portions characterized by the presence of secondary tissues, but there is not yet agreement about the putative tissue source providing the cells competent to become founder cells of a new root primordium. Scope:We suggest models of possible regulatory mechanisms for inducing specific root vascular cambium (VC) stem cells to abandon their activity in the production of xylem and phloem elements and to start instead the construction of a new lateral root primordium. Considering the ontogenic nature of the VC, the models which we suggest are the result of a comparative review of mechanisms known to control the activity of stem cells in the root apical meristem, procambium and VC. Stem cells in the root meristems can inherit various competences to play different roles, and their fate could be decided in response to cross-talk between endogenous and exogenous signals. Conclusions:We have found a high degree of relatedness among the regulatory mechanisms controlling the various root meristems. This fact suggests that competence to form new lateral roots can be inherited by some stem cells of the VC lineage. This kind of competence could be represented by a sensitivity of specific stem cells to factors such as those presented in our models.

The urbanization process, which began with the Industrial Revolution, has undergone a considerable increase over the past few decades. Urbanization strongly affects ecological processes, often deleteriously, because it is associated with a decrease in green spaces (areas of land covered by vegetation), loss of natural habitats, increased rates of species extinction, a greater prevalence of invasive and exotic species, and anthropogenic pollutant accumulation. In urban environments, green spaces play a key role by providing many ecological benefits and contributing to human psychophysical well-being. It is known that interactions between plants and microorganisms that occur in the rhizosphere are of paramount importance for plant health, soil fertility, and the correct functioning of plant ecosystems. The growing diffusion of DNA sequencing technologies and "omics" analyses has provided increasing information about the composition, structure, and function of the rhizomicrobiota. However, despite the considerable amount of data on rhizosphere communities and their interactions with plants in natural/rural contexts, current knowledge on microbial communities associated with plant roots in urban soils is still very scarce. The present review discusses both plant–microbe dynamics and factors that drive the composition of the rhizomicrobiota in poorly investigated urban settings and the potential use of beneficial microbes as an innovative biological tool to face the challenges that anthropized environments and climate change impose. Unravelling urban biodiversity will contribute to green space management, preservation, and development and, ultimately, to public health and safety. [ABSTRACT FROM AUTHOR]

Common bean landraces, besides contributing to the preservation of the social and cultural identity of the local communities of the production area, typically display adaptability to adverse agro-climatic conditions. This adapted germplasm is a repository of the gene pool and also shows typical phytochemical profiles, representing an essential source of bioactive components. However, genetic erosion is progressively affecting this genetic material, creating serious threats to its cultivation in marginal rural areas and use as a source of biodiversity and bioproducts. In the present work, a comprehensive approach was used to characterize the seed morpho-colorimetric traits, genetic diversity, and NMR metabolomic profiles of three Italian common bean landraces. Specific physiological and biochemical features (antioxidant molecules, osmolytes, structural reorganization of photosynthetic pigment, etc.), together with the accumulation of distinctive metabolites, contribute to the description of the observed diversity among the landraces in terms of the salt stress response and antiproliferative abilities on intestinal human cancer cells. This information could be useful in establishing their value in terms of environmental and/or human health "service", both essential to translating landraces into competitive products, a prerequisite for envisioning appropriate strategies for their conservation and a driving force for the revitalization of marginal rural areas. [ABSTRACT FROM AUTHOR]

Climate challenges impose the need for successful afforestation strategies which will increase the amount of carbon sequestered from the atmosphere. In practice, this means evaluation of suitable plant species and management practices for the long-term effects to prove beneficial. In the present study we employed a clasmometric approach to look into biomass partitioning in two tree species, Populus sibirica and Ulmus pumila, which have been included in the formation of the Green Belt project in Asia. Comparing the total biomass comprised of the above ground (AG) and below ground (BG) biomass of trees grown in different irrigation and fertilization regimes, we aim to better understand where the two species invest more biomass as a tool to deal with the environmental challenges. The results suggest that these two tree species prioritize different aspects of development when faced with various challenges. U. pumilia tends to be more resistant to drought making it favorable for the semi-arid and arid regions. P. sibirica is more sensitive to the lack of water but shows greater potential in terms of biomass production (especially AG biomass) and, therefore, overall higher C-sequestration. The fertilization treatments made no significant impact on tree development on Mongolian steppe soil. [ABSTRACT FROM AUTHOR]

Plant growth and development are affected by several environmental factors, among which soil nutrient availability. Biochar addition to soil is recognized to exert beneficial effects on soil fertility and thus plant growth; furthermore, it is a promising option for climate change mitigation. However, multi-species studies and meta-analyses have indicated considerable variations in biochar responses among plant species. To date, information on the biochar effect on plants, especially at molecular level, is still scarce. Using a multi-target approach with a model plant such as tomato, we demonstrate that biochar has a negligible effect on soil nutrient content and plant growth, even if it misbalances the plant photosynthetic machinery, as well as mechanisms recognizing pathogen-derived molecules. Ethylene could be one of the signal-molecule driving the alteration of tomato-pathogen recognition signaling by inactivation of vesicle trafficking. All these modifications could be at the basis of the increased susceptibility of biochar-treated plants to pathogen attack. Further organ-specific and tissue-specific multi-level studies, from high-resolution internal processes towards high-throughput external phenotyping, coupled with powerful biostatistic and informatic analysis, will help to decipher, in a network-type fashion, all the factors and signaling mechanisms related to the complex interaction between different plant, soil and biochar types. [ABSTRACT FROM AUTHOR]