1,721,003 research outputs found
The maize PIN gene family of auxin transporters
Full text linkAuxin is a key regulator of plant development and its differential distribution in plant tissues, established by a polar cell to cell transport, can trigger a wide range of developmental processes. A few members of the two families of auxin efflux transport proteins, PIN-formed (PIN and P-glycoprotein (ABCB/PGP, have so far been characterized in maize. Nine new Zea mays auxin efflux carriers PIN family members and two maize PIN-like genes have now been identified. Four members of PIN1 (named ZmPIN1a-d cluster, one gene homologous to AtPIN2 (ZmPIN2, three orthologs of PIN5 (ZmPIN5a-c, one gene paired with AtPIN8 (ZmPIN8, and three monocot-specific PINs (ZmPIN9, ZmPIN10a, and ZmPIN10b were cloned and the phylogenetic relationships between early-land plants, monocots, and eudicots PIN proteins investigated, including the new maize PIN proteins. Tissue-specific expression patterns of the 12 maize PIN genes, 2 PIN-like genes and ZmABCB1, an ABCB auxin efflux carrier, were analyzed together with protein localization and auxin accumulation patterns in normal conditions and in response to drug applications. ZmPIN gene transcripts have overlapping expression domains in the root apex, during male and female inflorescence differentiation and kernel development. However, some PIN family members have specific tissue localization: ZmPIN1d transcript marks the L1 layer of the shoot apical meristem and inflorescence meristem during the flowering transition and the monocot-specific ZmPIN9 is expressed in the root endodermis and pericycle. The phylogenetic and gene structure analyses together with the expression pattern of the ZmPIN gene family indicate that subfunctionalization of some maize PINs can be associated to the differentiation and development of monocot-specific organs and tissues and might have occurred after the divergence between dicots and monocots. © 2012 Forestan, Farinati and Varotto
Unraveling the role of PIN auxin efflux carriers in mediating polar auxin transport and accumulation in Zea mays: phylogenetic analysis, expression patterns and subcellular trafficking
No full textPersistently High Levels of Coagulation Factor XI as a Risk Factor for Venous Thrombosis
Full text linkCoagulation factor XI (FXI) promotes fibrin formation and inhibits fibrinolysis. Elevated plasma FXI levels, limited to a single measurement, are associated with a higher thrombotic risk. Our case-control study aimed to identify the effect of persistently increased plasma FXI levels on the risk of deep vein thrombosis (DVT). All patients evaluated between January 2016 and January 2018 for a first episode of proximal DVT of the lower extremity were considered for enrolment. Plasma FXI levels were measured at least 1 month after the discontinuation of anticoagulant treatment (T1). The patients with increased plasma FXI levels (>90th percentile of controls) were tested again 3 months later (T2). Among the 200 enrolled patients (M/F 114/86, age range 26-87 years), 47 patients had increased plasma FXI levels at T1 and16 patients had persistently increased plasma FXI levels at T2. The adjusted odds ratio for DVT was 2.4 (95% CI, 1.3 to 5.5, p < 0.001) for patients with increased FXI levels at T1 and 5.2 (95% CI, 2.3 to 13.2, p < 0.001) for patients with persistently high FXI levels at T2. Elevated FXI levels constitute a risk factor for deep vein thrombosis, and this risk nearly doubled in patients with persistently increased plasma FXI levels. Larger prospective studies are needed to confirm our findings
UNDERSTANDING EPIALLELES FORMATION IN RESPONSE TO ENVIRONMENTAL CUES AND THEIR HERITABILITY IN PLANTS
No full textEpigenetics is defined as the study of heritable
traits that do not depend on the primary DNA sequence.
The discovery of epigenetic mechanisms acting
on chromatin to regulate global gene expression has revealed
how heritable variation need not be sequencebased.
Particularly, environmental factors can induce novel
variation through the activation of specific epigenetic
mechanisms that determine mutations of spatial and temporal
pattern of gene expression. The carriers of epigenetic
information are identified in DNA methylation, histone
tails post-translation modifications and histone variants.
Specific combinations of these marks can influence
chromatin structure that in turn affects transcription and
genome stability. The environment can induce various
types of epigenetic changes leading to alternative gene
expression patterns, which can either be restricted to somatic
and vegetative tissues or propagated through mitotic
cell divisions. Of particular interest is the distinction between
transient and stable changes in epigenetic marks
and the formation and maintenance of epialles. Epigenetic
alleles or epialleles show different distribution of epigenetic
marks in their sequence and can exhibit distinct
phenotypes. The search for natural occurring epialles and
the understanding of the mechanisms leading to their formation
and maintenance, particularly in response to environmental
cues, is a great challenge for the future
De novo identification of sRNA loci and non-coding RNAs by high-throughput sequencing
No full textNon-coding RNA transcripts, such as long non-coding RNAs, miRNAs, siRNAs, and transposon-originating transcripts, are involved in the regulation of RNA stability, protein translation, and/or the modulation of chromatin states. RNA-Seq can be used to catalog this diversity of novel transcripts and a joint analysis of these transcriptomic data can provide useful insights into epigenetic regulation of dynamic responses such as the stress response, which may not be deciphered from individual analysis of single transcript categories. Here, we present a protocol that allows the identification and analysis of small RNAs and long non-coding RNAs, together with the comparison of these species between different sample types
Biodiversity of local Italian grapevine cultivars detected by SSR markers
No full textGrapevine cultivation is an age-old tradition in the Veneto region of Italy where many ancient cultivars are still grown. Some of these cultivars are recognised as producing important Controlled Designations of Origin (D.O.C.) wines, while other local types have been lost through substitution by international cultivars. Despite the large number of ancient cultivars present in the Veneto region, many are not registered in the Italian Ampelographic Catalogue and therefore risk extinction. Moreover, synonyms and homonyms have often become popular at the local level, thus rendering correct varietal identification tricky. Our aim was to characterize ancient local cultivars to preserve the germoplasm and investigate their genetic relationships. Genetic variability was assessed in 18 local varieties using nuclear simple sequence repeat (SSR) markers to identify the most similar groups and verify if these groupings are in agreement with the known history of the cultivars
ZmPIN1a and ZmPIN1b encode two novel putative candidates for polar auxin transport and plant architecture determination of maize
No full textShoot apical meristems produce organs in a highly stereotypic pattern that involves auxin. Auxin is supposed to be actively transported from cell to cell by influx (AUXIN/LIKE AUXIN proteins) and efflux (PIN-FORMED proteins) membrane carriers. Current hypotheses propose that, at the meristem surface, PIN proteins create patterns of auxin gradients that, in turn, create patterns of gene expression and morphogenesis. These hypotheses are entirely based on work in Arabidopsis (Arabidopsis thaliana). To verify whether these models also apply to other species, we studied the behavior of PIN proteins during maize (Zea mays) development. We identified two novel putative orthologs of AtPIN1 in maize and analyzed their expression pattern during development. The expression studies were complemented by immunolocalization studies using an anti-AtPIN1 antibody. Interestingly, the maize proteins visualized by this antibody are almost exclusively localized in subepidermal meristematic layers. Both tassel and ear were characterized by a compact group of cells, just below the surface, carrying PIN. In contrast to or to complement what was shown in Arabidopsis, these results point to the importance of internally localized cells in the patterning process. We chose the barren inflorescence2 (bif2) maize mutant to study the role of auxin polar fluxes in inflorescence development. In severe alleles of bif2, the tassel and the ear present altered ZmPIN1a and ZmPIN1b protein expression and localization patterns. In particular, the compact groups of cells in the tassel and ear of the mutant were missing. We conclude that BIF2 is important for PIN organization and could play a role in the establishment of polar auxin fluxes in maize inflorescence, indirectly modulating the process of axillary meristem formation and development. © 2006 American Society of Plant Biologists
Transcriptomic analysis reveals a role for 24-EpiBrassinolide in modulating plant growth in maize seedlings.
No full textMeta-analysis of RNA-Seq studies reveals genes with dominant functions during flower bud endo- to eco-dormancy transition in Prunus species
Full text linkAbstract In deciduous fruit trees, entrance into dormancy occurs in later summer/fall, concomitantly with the shortening of day length and decrease in temperature. Dormancy can be divided into endodormancy, ecodormancy and paradormancy. In Prunus species flower buds, entrance into the dormant stage occurs when the apical meristem is partially differentiated; during dormancy, flower verticils continue their growth and differentiation. Each species and/or cultivar requires exposure to low winter temperature followed by warm temperatures, quantified as chilling and heat requirements, to remove the physiological blocks that inhibit budburst. A comprehensive meta-analysis of transcriptomic studies on flower buds of sweet cherry, apricot and peach was conducted, by investigating the gene expression profiles during bud endo- to ecodormancy transition in genotypes differing in chilling requirements. Conserved and distinctive expression patterns were observed, allowing the identification of gene specifically associated with endodormancy or ecodormancy. In addition to the MADS-box transcription factor family, hormone-related genes, chromatin modifiers, macro- and micro-gametogenesis related genes and environmental integrators, were identified as novel biomarker candidates for flower bud development during winter in stone fruits. In parallel, flower bud differentiation processes were associated to dormancy progression and termination and to environmental factors triggering dormancy phase-specific gene expression
The Role of PIN Auxin Efflux Carriers in Polar Auxin Transport and Accumulation and Their Effect on Shaping Maize Development
No full textn plants, proper seed development and the continuing post-embryonic organogenesis both require that different cell types are correctly differentiated in response to internal and external stimuli. Among internal stimuli, plant hormones and particularly auxin and its polar transport (PAT) have been shown to regulate a multitude of plant physiological processes during vegetative and reproductive development. Although our current auxin knowledge is almost based on the results from researches on the eudicot Arabidopsis thaliana, during the last few years, many studies tried to transfer this knowledge from model to crop species, maize in particular. Applications of auxin transport inhibitors, mutant characterization, and molecular and cell biology approaches, facilitated by the sequencing of the maize genome, allowed the identification of genes involved in auxin metabolism, signaling, and particularly in polar auxin transport. PIN auxin efflux carriers have been shown to play an essential role in regulating PAT during both seed and post-embryonic development in maize. In this review, we provide a summary of the recent findings on PIN-mediated polar auxin transport during maize development. Similarities and differences between maize and Arabidopsis are analyzed and discussed, also considering that their different plant architecture depends on the differentiation of structures whose development is controlled by auxins
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