In the context of climate changes, clarifying the causes underlying tree phenotypic plasticity and adaptation is crucial. Studies suggest a role of epigenetic mechanisms in response to external stimuli, raising the question whether such processes can promote acclimation of trees exposed to adverse climate conditions. Recently, we revealed an environmental epigenetic footprint in the shoot apical meristem (SAM) which could partially be transmitted mitotically, for several months, up until the winter-dormant bud in field conditions. Here, we extended our previous analysis to the leaves of the same P. deltoides×P. nigra clones. We aimed at estimating the range of developmentally, genetically, and environmentally induced variations on DNA methylation. We showed that only the first leaves emerging from the SAM displayed variations of DNA methylation under changing water conditions. We also found that these variations are genotype- and pedoclimatic site-dependent. Altogether, our data raised questions and perspectives on the direct acquisition, the maintenance of environmentally induced DNA methylation changes, and their mitotic transmission from the SAM to the first emerging leaves.

• MeSH
• genotyp MeSH
• listy rostlin genetika   MeSH
• meristém genetika   růst a vývoj   MeSH
• metylace DNA genetika   MeSH
• Populus genetika   růst a vývoj   MeSH
• stromy genetika   růst a vývoj   MeSH
• životní prostředí * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The cytokinin response factors (CRFs) are a group of related AP2/ERF transcription factors that are transcriptionally induced by cytokinin. Here we explore the role of the CRFs in Arabidopsis thaliana growth and development by analyzing lines with decreased and increased CRF function. While single crf mutations have no appreciable phenotypes, disruption of multiple CRFs results in larger rosettes, delayed leaf senescence, a smaller root apical meristem (RAM), reduced primary and lateral root growth, and, in etiolated seedlings, shorter hypocotyls. In contrast, overexpression of CRFs generally results in the opposite phenotypes. The crf1,2,5,6 quadruple mutant is embryo lethal, indicating that CRF function is essential for embryo development. Disruption of the CRFs results in partially insensitivity to cytokinin in a root elongation assay and affects the basal expression of a significant number of cytokinin-regulated genes, including the type-A ARRs, although it does not impair the cytokinin induction of the type-A ARRs. Genes encoding homeobox transcription factors are mis-expressed in the crf1,3,5,6 mutant, including STIMPY/WOX9 that is required for root and shoot apical meristem maintenance roots and which has previously been linked to cytokinin. These results indicate that the CRF transcription factors play important roles in multiple aspects of plant growth and development, in part through a complex interaction with cytokinin signaling.

• MeSH
• Arabidopsis genetika   růst a vývoj   fyziologie   MeSH
• cytokininy metabolismus   MeSH
• exprese genu MeSH
• fenotyp MeSH
• homeodoménové proteiny genetika   metabolismus   MeSH
• kořeny rostlin genetika   růst a vývoj   fyziologie   MeSH
• meristém genetika   růst a vývoj   fyziologie   MeSH
• mutace MeSH
• proteiny huseníčku genetika   metabolismus   MeSH
• regulace genové exprese u rostlin MeSH
• regulátory růstu rostlin metabolismus   MeSH
• semenáček genetika   růst a vývoj   fyziologie   MeSH
• signální transdukce * MeSH
• transkripční faktory genetika   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH

Plant architecture is one of the key factors that affect plant survival and productivity. Plant body structure is established through the iterative initiation and outgrowth of lateral organs, which are derived from the shoot apical meristem and root apical meristem, after embryogenesis. Here we report that ADP1, a putative MATE (multidrug and toxic compound extrusion) transporter, plays an essential role in regulating lateral organ outgrowth, and thus in maintaining normal architecture of Arabidopsis. Elevated expression levels of ADP1 resulted in accelerated plant growth rate, and increased the numbers of axillary branches and flowers. Our molecular and genetic evidence demonstrated that the phenotypes of plants over-expressing ADP1 were caused by reduction of local auxin levels in the meristematic regions. We further discovered that this reduction was probably due to decreased levels of auxin biosynthesis in the local meristematic regions based on the measured reduction in IAA levels and the gene expression data. Simultaneous inactivation of ADP1 and its three closest homologs led to growth retardation, relative reduction of lateral organ number and slightly elevated auxin level. Our results indicated that ADP1-mediated regulation of the local auxin level in meristematic regions is an essential determinant for plant architecture maintenance by restraining the outgrowth of lateral organs.

• MeSH
• Arabidopsis genetika   růst a vývoj   MeSH
• kořeny rostlin genetika   růst a vývoj   metabolismus   MeSH
• květy genetika   růst a vývoj   MeSH
• kyseliny indoloctové metabolismus   MeSH
• meristém růst a vývoj   metabolismus   MeSH
• proteiny huseníčku genetika   metabolismus   MeSH
• proteiny přenášející organické kationty genetika   MeSH
• regulace genové exprese u rostlin MeSH
• výhonky rostlin genetika   růst a vývoj   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

BACKGROUND AND AIMS: The maize lrt1 (lateral rootless1) mutant is impaired in its development of lateral roots during early post-embryonic development. The aim of this study was to characterize, in detail, the influences that the mutation exerts on lateral root initiation and the subsequent developments, as well as to describe the behaviour of the entire plant under variable environmental conditions. METHODS: Mutant lrt1 plants were cultivated under different conditions of hydroponics, and in between sheets of moist paper. Cleared whole mounts and anatomical sections were used in combination with both selected staining procedures and histochemical tests to follow root development. Root surface permeability tests and the biochemical quantification of lignin were performed to complement the structural data. KEY RESULTS: The data presented suggest a redefinition of lrt1 function in lateral roots as a promoter of later development; however, neither the complete absence of lateral roots nor the frequency of their initiation is linked to lrt1 function. The developmental effects of lrt1 are under strong environmental influences. Mutant primordia are affected in structure, growth and emergence; and the majority of primordia terminate their growth during this last step, or shortly thereafter. The lateral roots are impaired in the maintenance of the root apical meristem. The primary root shows disturbances in the organization of both epidermal and subepidermal layers. The lrt1-related cell-wall modifications include: lignification in peripheral layers, the deposition of polyphenolic substances and a higher activity of peroxidase. CONCLUSIONS: The present study provides novel insights into the function of the lrt1 gene in root system development. The lrt1 gene participates in the spatial distribution of initiation, but not in its frequency. Later, the development of lateral roots is strongly affected. The effect of the lrt1 mutation is not as obvious in the primary root, with no influences observed on the root apical meristem structure and maintenance; however, development of the epidermis and cortex are impaired.

• MeSH
• buněčná stěna metabolismus   MeSH
• epidermis rostlin anatomie a histologie   genetika   růst a vývoj   MeSH
• hydroponie MeSH
• kořeny rostlin cytologie   genetika   růst a vývoj   MeSH
• kukuřice setá cytologie   genetika   růst a vývoj   MeSH
• lignin metabolismus   MeSH
• meristém cytologie   genetika   růst a vývoj   MeSH
• mutace MeSH
• polyfenoly metabolismus   MeSH
• regulace genové exprese u rostlin * MeSH
• rostlinné proteiny genetika   metabolismus   MeSH
• semenáček cytologie   genetika   růst a vývoj   MeSH
• výhonky rostlin cytologie   genetika   růst a vývoj   MeSH
• vývojová regulace genové exprese MeSH
• životní prostředí MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

To maintain the activity of meristems is an absolute requirement for plant growth and development, and the role of the plant hormones auxin and cytokinin in apical meristem function is well established. Only little attention has been given, however, to the function of the reactive oxygen species (ROS) gradient along meristematic tissues and its interplay with hormonal regulatory networks. The interdependency between auxin-related, cytokinin-related and ROS-related circuits controls primary growth and development while modulating plant morphology in response to detrimental environmental factors. Because ROS interaction with redox-active compounds significantly affects the cellular redox gradient, the latter constitutes an interface for crosstalk between hormone and ROS signalling pathways. This review focuses on the mechanisms underlying ROS-dependent interactions with redox and hormonal components in shoot and root apical meristems which are crucial for meristems maintenance when plants are exposed to environmental hardships. We also emphasize the importance of cell type and the subcellular compartmentalization of ROS and redox networks to obtain a holistic understanding of how apical meristems adapt to stress.

• MeSH
• cytokininy metabolismus   MeSH
• homeostáza MeSH
• kyseliny indoloctové metabolismus   MeSH
• oxidace-redukce MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• vývoj rostlin * MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Parallel research on multiple model organisms shows that while some principles of telomere biology are conserved among all eukaryotic kingdoms, we also find some deviations that reflect different evolutionary paths and life strategies, which may have diversified after the establishment of telomerase as a primary mechanism for telomere maintenance. Much more than animals, plants have to cope with environmental stressors, including genotoxic factors, due to their sessile lifestyle. This is, in principle, made possible by an increased capacity and efficiency of the molecular systems ensuring maintenance of genome stability, as well as a higher tolerance to genome instability. Furthermore, plant ontogenesis differs from that of animals in which tissue differentiation and telomerase silencing occur during early embryonic development, and the "telomere clock" in somatic cells may act as a preventive measure against carcinogenesis. This does not happen in plants, where growth and ontogenesis occur through the serial division of apical meristems consisting of a small group of stem cells that generate a linear series of cells, which differentiate into an array of cell types that make a shoot and root. Flowers, as generative plant organs, initiate from the shoot apical meristem in mature plants which is incompatible with the human-like developmental telomere shortening. In this review, we discuss differences between human and plant telomere biology and the implications for aging, genome stability, and cell and organism survival. In particular, we provide a comprehensive comparative overview of telomere proteins acting in humans and in Arabidopsis thaliana model plant, and discuss distinct epigenetic features of telomeric chromatin in these species.

• Publikační typ
• časopisecké články MeSH
• přehledy MeSH