98 research outputs found
Analisi comparata del controllo molecolare dell'induzione alla fioritura: ruolo dei geni OsMADS22/OsMADS47 e SVP/AGL24 rispettivamente in riso e Arabidopsis
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Characterization of rem genes involved in the reproductive development of arabidopsis thaliana
No full textThe REM transcriptional factor family belongs to the plant-specific B3 DNA binding domain superfamily, in Arabidopsis thaliana this family is composed of 45 genes preferentially expressed during flower and seed development among which only a few members have been associated to a function. We focused our attention on three homologous members of this family, REM34 , REM35 and REM36, which are expressed in the inflorescence meristem and in the earliest stages of flower development. To uncover their role RNA interference lines for the simultaneous silencing of these three genes were analysed. At the same time, a CRISPR/Cas9 approach was chosen in order to generate single and multiple mutants. The RNAi lines and the CRISPR/Cas9 mutants showed an aberrant phyllotaxis, a higher rate of flower production and, only in the RNAi lines, an arrest in the female gametophyte in the FG1/FG2 phase.
YUCCA1 , which is coexpressed with REM34 and its closest homologs YUC4 , and YUC6 were found to be downregulated in these RNAi lines. These genes code for flavin monooxygenase proteins involved in auxin biosynthesis and their mutation or misregulation phenocopies RNAi lines. All these evidence suggest that REM34 , REM35 and REM36 could be involved in the regulation of auxin biosynthesis at the level of the inflorescence and flower meristem
Crop Reproductive Meristems in the Genomic Era: A Brief Overview
No full textModulation of traits beneficial for cultivation and yield is one of the main goals of crop improvement. One of the targets for enhancing productivity is changing the architecture of inflorescences since in many species it determines fruit and seed yield. Inflorescence shape and organization is genetically established during the early stages of reproductive development and depends on the number, arrangement, activities, and duration of meristems during the reproductive phase of the plant life cycle. Despite the variety of inflorescence architectures observable in nature, many key aspects of inflorescence development are conserved among different species. For instance, the genetic network in charge of specifying the identity of the different reproductive meristems, which can be indeterminate or determinate, seems to be similar among distantly related species. The availability of a large number of published transcriptomic datasets for plants with different inflorescence architectures, allowed us to identify transcription factor gene families that are differentially expressed in determinate and indeterminate reproductive meristems. The data that we review here for Arabidopsis, rice, barley, wheat, and maize, particularly deepens our knowledge of their involvement in meristem identity specification
Molecular mechanism of BASIC PENTACYSTEINE factors and MADS-box transcription factor SVP involved in reproductive development in the model species Arabidopsis thaliana
No full textThe development of flower meristems and fruits are two extremely important agronomical traits. MADS-domain transcription factors (TFs) are key regulators of these processes and we are focusing on how these TFs and their interacting partners control the regulatory network leading to reproductive meristem formation and fruit development in the model plant Arabidopsis thaliana.
An excellent starting point for this research project is the large amount of information and tools that we and other groups have already generated for one of the key players in both vegetative and reproductive meristem development: the MADS-domain TF SHORT VEGETATIVE PHASE (SVP). SVP acts as a repressor of the floral transition in the vegetative meristem and later as a key factor floral meristem identity factor (Gregis et al., 2013). Moreover we have recently characterized the function of the complex composed of SVP and BASIC PENTACYSTEINE factors (BPCs) (Simonini et al., 2012). BPCs are transcription factors with affinity to GA-repeated sequences, involved in transcription regulation through their interaction with other TFs and chromatin modifiers. We showed that BPC binding sites are important for BPC recruitment to the DNA but also for binding of SVP to nearby MADS-domain binding sites (CArG boxes).
We focus our attention on the molecular mechanisms by which SVP and its interaction partners control their targets. MADS-domain factors have been studied deeply from a genetic point of view and are recognised as key controllers of development in plants. However, little is known about the molecular aspects (DNA binding mechanisms, recruitment of complex members etc.).
We are studying two important interconnected research lines that are related to the regulatory mechanisms that underlay reproductive development: (i) the mechanistic molecular aspects of target gene regulation by SVP and its interacting partners BPCs and (ii) the analysis of bpc multiple mutants combinations phenotype and the characterization of their role in fruit development
Causes of death and risk factors among HIV-infected persons in the HAART era: analysis of a large urban cohort
No full textWe aimed to examine the clinical outcome in HIV-1-infected patients after more than 10 years of highly active antiretroviral therapy (HAART)
Assessing the role of REM13, REM34 and REM46 during the transition to the reproductive phase in Arabidopsis thaliana
No full textREM (reproductive meristem) transcription factors have been proposed as regulators of plant reproductive development mainly based on their specific expression patterns in reproductive structures, but their roles are still largely unknown probably because of their redundancy. We selected three REM genes (REM13, REM34 and REM46) for functional analysis, based on their genome position and/or co-expression data. Our results suggest that these genes have a role in flowering time regulation and may modulate cell cycle progression. In addition, protein interaction experiments revealed that REM34 and REM46 interact with each other, suggesting that they might work cooperatively to regulate cell division during inflorescence meristem commitment. Previous attempts of using co-expression data as a guide for functional analysis of REMs were limited by the transcriptomic data available at the time. Our results uncover previously unknown functions of three members of the REM family of Arabidopsis thaliana and open the door to more comprehensive studies of the REM family, where the combination of co-expression analysis followed by functional studies might contribute to uncovering the biological roles of these proteins and the relationship among them
Dairy farmers' attitudes towards grazing. Results from a preliminary survey in Germany
No full textThe generally positive perception of grazed grassland combines aspects of landscape, aesthetic values, biodiversity and concern for animal welfare. Many consumers are in favor of grazing and there is a rising political interest to support farms, which let their cows graze. In order to understand the motivations and the constraints dairy farmers are facing, 46 German dairy farmers were interviewed. Besides questions concerning factors like farm size, milk yield or number of cows, the farmers were asked about their attitudes towards grazing. Farmers, who let their cows graze, generally judge grazing more positive than farmers from non-grazing-farms. On top of that, they denote their knowledge about grazing as good; farmers from non-grazing farms and from siesta-grazing farms describe their knowledge about grazing management as poor. Grazing farms usually have a greater proportion of grassland that is close to the farm
Dairy farmers' attitudes towards grazing. Results from a preliminary survey in Germany
No full textThe generally positive perception of grazed grassland combines aspects of landscape, aesthetic values, biodiversity and concern for animal welfare. Many consumers are in favor of grazing and there is a rising political interest to support farms, which let their cows graze. In order to understand the motivations and the constraints dairy farmers are facing, 46 German dairy farmers were interviewed. Besides questions concerning factors like farm size, milk yield or number of cows, the farmers were asked about their attitudes towards grazing. Farmers, who let their cows graze, generally judge grazing more positive than farmers from non-grazing-farms. On top of that, they denote their knowledge about grazing as good; farmers from non-grazing farms and from siesta-grazing farms describe their knowledge about grazing management as poor. Grazing farms usually have a greater proportion of grassland that is close to the farm
Uncovering genetic and molecular interactions among floral meristem identity genes in Arabidopsis thaliana
No full textThe inflorescence meristem produces floral primordia that remain undifferentiated during the first stages of flower development. Genes controlling floral meristem identity include LEAFY (LFY), APETALA1 (AP1), CAULIFLOWER (CAL), LATE MERISTEM IDENTITY 1 (LMI1), SHORT VEGETATIVE PHASE (SVP) and AGAMOUS-LIKE24 (AGL24). The lfy mutant shows partial reversions of flowers into inflorescence shoot-like structures and this phenotype is enhanced in the lfy ap1 double mutant. Here we show that combining the lfy mutant with agl24 and svp single mutants or with the agl24 svp double mutant enhances the lfy phenotype and that the lfy agl24 svp triple mutant phenocopies the lfy ap1 double mutant. Analysis of the molecular interactions between LFY, AGL24 and SVP showed that LFY is a repressor of AGL24 and SVP, whereas LMI1 is a positive regulator of these genes. Moreover, AGL24 and SVP positively regulate AP1 and LFY by direct binding to their regulatory regions. Since all these genes are important for establishing floral meristem identity, regulatory loops are probably important to maintain the correct relative expression levels of these genes
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