Genetic Diversity and Population Structure Assessed Using Microsatellite (SSR) Markers from Relict Populations of (Nymphaeaceae).

The genus (Nymphaeaceae) comprises aquatic plant species inhabiting freshwater bodies of the Northern hemisphere temperate regions known as yellow water-lilies. and are the only representatives in the European continent and present different ecologies: the former is a widespread generalist, while the latter is restricted to northern latitudes or high-altitudes due to its requirements for colder and oligotrophic waters. The Central Europe mountainous areas, the Massif Central (France) and the Cantabrian Mountains (north Iberian Peninsula) harbor relict isolated populations endangered by eutrophication and hybridization with .

In Vitro Plant Regeneration in Conifers: The Role of and Gene Families.

Conifers are a group of woody plants with an enormous economic and ecological importance. Breeding programs are necessary to select superior varieties for planting, but they have many limitations due to the biological characteristics of conifers. Somatic embryogenesis (SE) and de novo organogenesis (DNO) from in vitro cultured tissues are two ways of plant mass propagation that help to overcome this problem.

Modulation of plant root growth by nitrogen source-defined regulation of polar auxin transport.

Availability of the essential macronutrient nitrogen in soil plays a critical role in plant growth, development, and impacts agricultural productivity. Plants have evolved different strategies for sensing and responding to heterogeneous nitrogen distribution. Modulation of root system architecture, including primary root growth and branching, is among the most essential plant adaptions to ensure adequate nitrogen acquisition.

The Arabidopsis NRT1.1 transceptor coordinately controls auxin biosynthesis and transport to regulate root branching in response to nitrate.

In agricultural systems, nitrate is the main source of nitrogen available for plants. Besides its role as a nutrient, nitrate has been shown to act as a signal molecule in plant growth, development, and stress responses. In Arabidopsis, the NRT1.

SYNERGISTIC ON AUXIN AND CYTOKININ 1 positively regulates growth and attenuates soil pathogen resistance.

Plants as non-mobile organisms constantly integrate varying environmental signals to flexibly adapt their growth and development. Local fluctuations in water and nutrient availability, sudden changes in temperature or other abiotic and biotic stresses can trigger changes in the growth of plant organs. Multiple mutually interconnected hormonal signaling cascades act as essential endogenous translators of these exogenous signals in the adaptive responses of plants.

Hormonal and gene dynamics in de novo shoot meristem formation during adventitious caulogenesis in cotyledons of Pinus pinea.

Several members of WOX and KNOX gene families and several plant growth regulators, basically cytokinins and auxins, play a key role during adventitious caulogenesis in the conifer Pinus pinea. Similar to Arabidopsis thaliana, Pinus pinea shoot organogenesis is a multistep process. However, there are key differences between both species, which may alter the underlying physiological and genetic programs.

CUP-SHAPED COTYLEDON1 (CUC1) and CUC2 regulate cytokinin homeostasis to determine ovule number in Arabidopsis.

Seeds derive from ovules upon fertilization and therefore the total number of ovules determines the final seed yield, a fundamental trait in crop plants. Among the factors that co-ordinate the process of ovule formation, the transcription factors CUP-SHAPED COTYLEDON 1 (CUC1) and CUC2 and the hormone cytokinin (CK) have a particularly prominent role. Indeed, the absence of both CUC1 and CUC2 causes a severe reduction in ovule number, a phenotype that can be rescued by CK treatment.

Light Controls Cytokinin Signaling via Transcriptional Regulation of Constitutively Active Sensor Histidine Kinase CKI1.

In plants, the multistep phosphorelay (MSP) pathway mediates a range of regulatory processes, including those activated by cytokinins. The cross talk between cytokinin response and light has been known for a long time. However, the molecular mechanism underlying the interaction between light and cytokinin signaling remains elusive.

Nitrate Controls Root Development through Posttranscriptional Regulation of the NRT1.1/NPF6.3 Transporter/Sensor.

Plants are able to modulate root growth and development to optimize their nitrogen nutrition. In Arabidopsis (Arabidopsis thaliana), the adaptive root response to nitrate (NO) depends on the NRT1.1/NPF6.

Cytokinin response factors regulate PIN-FORMED auxin transporters.

Auxin and cytokinin are key endogenous regulators of plant development. Although cytokinin-mediated modulation of auxin distribution is a developmentally crucial hormonal interaction, its molecular basis is largely unknown. Here we show a direct regulatory link between cytokinin signalling and the auxin transport machinery uncovering a mechanistic framework for cytokinin-auxin cross-talk.

Physiological and biochemical responses to severe drought stress of nine Eucalyptus globulus clones: a multivariate approach.

Seasonal drought, typical of temperate and Mediterranean environments, creates problems in establishing plantations and affects development and yield, and it has been widely studied in numerous species. Forestry fast-growing species such as Eucalyptus spp. are an important resource in such environments, selected clones being generally used for production purposes in plantations in these areas.

Systems approaches to study root architecture dynamics.

The plant root system is essential for providing anchorage to the soil, supplying minerals and water, and synthesizing metabolites. It is a dynamic organ modulated by external cues such as environmental signals, water and nutrients availability, salinity and others. Lateral roots (LRs) are initiated from the primary root post-embryonically, after which they progress through discrete developmental stages which can be independently controlled, providing a high level of plasticity during root system formation.

An integrative model of the control of ovule primordia formation.

Upon hormonal signaling, ovules develop as lateral organs from the placenta. Ovule numbers ultimately determine the number of seeds that develop, and thereby contribute to the final seed yield in crop plants. We demonstrate here that CUP-SHAPED COTYLEDON 1 (CUC1), CUC2 and AINTEGUMENTA (ANT) have additive effects on ovule primordia formation.

Spatiotemporal regulation of lateral root organogenesis in Arabidopsis by cytokinin.

The architecture of a plant's root system, established postembryonically, results from both coordinated root growth and lateral root branching. The plant hormones auxin and cytokinin are central endogenous signaling molecules that regulate lateral root organogenesis positively and negatively, respectively. Tight control and mutual balance of their antagonistic activities are particularly important during the early phases of lateral root organogenesis to ensure continuous lateral root initiation (LRI) and proper development of lateral root primordia (LRP).

Rapid responses of C14 clone of Eucalyptus globulus to root drought stress: Time-course of hormonal and physiological signaling.

The responses of juvenile plants of forest crops to drought stress are a key stage in the survival of forest populations. In this work, a suitable experimental system to study the early drought resistance mechanisms and signaling in a drought-tolerant clone (C14) of Eucalyptus globulus Labill is proposed. This system, using hydroponic culture and an osmotic agent, polyethylene glycol 8000, was demonstrated to induce severe stress in the root area, affecting the responses of the plantlets at the aerial level.

Caulogenic induction in cotyledons of stone pine (Pinus pinea): relationship between organogenic response and benzyladenine trends in selected families.

Adventitious bud formation in stone pine cotyledons cultured in the presence of benzyladenine (BA) has been proposed as a model for the study of in vitro shoot organogenesis in conifers. This is because of its advantageous characteristics including the requirement of only one plant growth regulator (BA), the synchronous fashion of its induction, and the homogeneity and low degree of differentiation of cotyledons. Although optimal culture conditions have been developed and are currently in use, we still lack data for BA dynamics in cotyledons cultured under these conditions, and the morphological description of the early induction stages has not, until now, been approached from a histological perspective.

Benzyladenine metabolism and temporal competence of Pinus pinea cotyledons to form buds in vitro.

Germination negatively affects adventitious shoot formation induced by cytokinins in pine cotyledons. To investigate the causes of this decrease in the organogenic response, uptake and metabolism of benzyladenine (BA) were studied in stone pine cotyledons (Pinus pinea) isolated from in vitro germinating embryos and cultured in bud induction medium. As embryos grew, cotyledons showed a progressive decrease in the amount of BA taken up from the medium.