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Mechanical stress in tree roots induces the production of reaction wood (RW) and the formation of new branch roots, both functioning to avoid anchorage failure and limb damage. The vascular cambium (VC) is the factor responsible for the onset of these responses as shown by their occurrence when all primary tissues and the root tips are removed. The data presented confirm that the VC is able to evaluate both the direction and magnitude of the mechanical forces experienced before coordinating the most fitting responses along the root axis whenever and wherever these are necessary. The coordination of these responses requires intense crosstalk between meristematic cells of the VC which may be very distant from the place where the mechanical stress is first detected. Signaling could be facilitated through plasmodesmata between meristematic cells. The mechanism of RW production also seems to be well conserved in the stem and this fact suggests that the VC could behave as a single structure spread along the plant body axis as a means to control the relationship between the plant and its environment. The observation that there are numerous morphological and functional similarities between different meristems and that some important regulatory mechanisms of meristem activity, such as homeostasis, are common to several meristems, supports the hypothesis that not only the VC but all apical, primary and secondary meristems present in the plant body behave as a single interconnected structure. We propose to name this structure "meristematic connectome" given the possibility that the sequence of meristems from root apex to shoot apex could represent a pluricellular network that facilitates long-distance signaling in the plant body. The possibility that the "meristematic connectome" could act as a single structure active in adjusting the plant body to its surrounding environment throughout the life of a plant is now proposed.

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]

Loop-mediated isothermal DNA amplification (LAMP) is an alternative method for the amplification of DNA sequences. It has been applied primarily for the detection of specific targets. We demonstrate the novel use of LAMP to amplify SSR alleles in a set of rice varieties and show the results to be consistent with analysis performed by PCR. Furthermore, we test the sensitivity of the assay and show it to amplify from near single copy target. Key words: rice microsatellite, LAMP, PCR, sensitivity. L'amplification isothermique en boucles (LAMP de l'anglais <>) est une methode alternative pour amplifier des sequences d'ADN. Elle a surtout ete employee pour la detection de cibles specifiques. Les auteurs font la demonstration de l'emploi de la methode LAMP pour l'amplification d'alleles SSR chez une collection de varietes de riz et ils montrent que les resultats concordent avec les resultats d'analyses realisees par PCR. Les auteurs examinent la sensibilite de la methode et ils montrent qu'elle est capable d'amplifier une cible s'approchant du niveau d'une simple copie. Mots-cles : microsatellite de riz, LAMP, PCR, sensibilite. [Traduit par la Redaction], Introduction Since its invention, polymerase chain reaction (PCR) (Saiki et al. 1985) has dominated the molecular biological research landscape on how genetic analysis is performed. At its core is the [...]