1,720,989 research outputs found
A plant spermine oxidase/dehydrogenase regulated by the proteasome and polyamines
No full textPolyamine oxidases (PAOs) are flavin-dependent enzymes involved in polyamine catabolism. In Arabidopsis five PAO genes (AtPAO1-AtPAO5) have been identified which present some common characteristics, but also important differences in primary structure, substrate specificity, subcellular localization, and tissue-specific expression pattern, differences which may suggest distinct physiological roles. In the present work, AtPAO5, the only so far uncharacterized AtPAO which is specifically expressed in the vascular system, was partially purified from 35S::AtPAO5-6His Arabidopsis transgenic plants and biochemically characterized. Data presented here allow AtPAO5 to be classified as a spermine dehydrogenase. It is also shown that AtPAO5 oxidizes the polyamines spermine, thermospermine, and N1-acetylspermine, the latter being the best in vitro substrate of the recombinant enzyme. AtPAO5 also oxidizes these polyamines in vivo, as was evidenced by analysis of polyamine levels in the 35S::AtPAO5-6His Arabidopsis transgenic plants, as well as in a loss-of-function atpao5 mutant. Furthermore, subcellular localization studies indicate that AtPAO5 is a cytosolic protein undergoing proteasomal control. Positive regulation of AtPAO5 expression by polyamines at the transcriptional and post-transcriptional level is also shown. These data provide new insights into the catalytic properties of the PAO gene family and the complex regulatory network controlling polyamine metabolism. © The Author 2014
Globe artichoke in vitro conservation protocol to meet germplasm preservation and production management
No full textA reliable and reproducible genotype-independent protocol for slow-growth storage of globe artichoke was established for the first time to meet two needs: genetic resources conservation and labour costs reduction in commercial laboratories. Plant responses to in vitro storage, genetic stability and field performance were the parameters used to evaluate the germplasm conservation conditions. Slow-growth storage was assessed, in our study, to preserve different artichoke genotypes for 12 months. Growth reduction was achieved supplementing osmotic agents, mannitol/sorbitol to the media. After 12 months of storage, culture survival across genotypes ranged from 65 to 85% and all the media tested supported 100% regrowth. Since associated in vitro stress can cause genetic instability, mother plants grown in the field and in vitro conserved plants were evaluated by means of molecular markers. Protocol suitability was further validated by a field test using an approved list of plant descriptor for globe artichoke. As far as we know there are no published reports on in vitro conservation protocol for globe artichoke applied to different genotypes and validated by an appropriate field test
Exploration to use of globe artichoke cell cultures as bioactive compounds production
No full textThe growing interest in foods rich in nutraceutical compounds has focused the attention of researchers towards the globe artichoke (Cynara cardunculus var. scolymus), by virtue of its high content in polyphenols (caffeoylquinic acids and flavones) and inulin, compounds with a high antioxidant capacity and prebiotic effects. The present study investigates the possibility to produce bioactive compounds from globe artichoke using an in vitro system to overcome the limitation of extracting useful metabolites from in vivo natural resources. To this end, experimental conditions for the establishment of globe artichoke cell cultures from leaf explants of a biochemically characterized late genotype were defined. High-producing callus/cell lines were isolated and selected. Cell cultures were analyzed for total polyphenol (TPC) and total caffeoylquinic acids (TCQA) content. The high TPC found in cell suspension cultures (about 25 g kg-1 of dry matter) of globe artichoke leaves highlighted the possibility of using this approach as innovative source of natural antioxidants by the pharmaceutical and food industry
Genetic fidelity of micropropagated globe artichoke plantlets
No full textIn vitro plant propagation and maintenance could face genetic mutation occurring during in vitro phases. The objective of the present study was to evaluate the genetic fidelity in micropropagated plantlets of globe artichoke. Leaves from both in vivo (mother plants in the field) and from in vitro material (multiplicated shoots) were analyzed over two years to determine intraclonal variation and to evaluate the influence of the number of subcultures on the generation of somaclonal variants. In this study, the usefulness of two different DNA-based techniques, inter simple sequence repeats (ISSR) and simple sequence repeat (SSR) markers was evaluated, in assessing the genetic stability of micropropagated plants of six ecotypes. Eight primers were successfully used to amplify the DNA demonstrating a different ability to detect genetic variation. ISSR techniques are efficient markers in showing the occurrence of the genetic changes that occur during the micropropagation process of globe artichoke. We conclude that when the tissue culture technique is used, the analysis of somaclonal variability could require more than one DNA-based technique; different markers detect different genome regions and have different polymorphic ability, as our results showed for SSR and ISSR markers. The consequences on breeding activities of present results are discussed
A validated slow-growth in vitro conservation protocol for globe artichoke germplasm: A cost-effective tool to preserve from wild to elite genotypes
No full textA reliable and reproducible genotype-independent protocol for slow-growth storage of globe artichoke was established for the first time to meet two needs: genetic resources conservation and labour costs reduction in commercial laboratories. Growth reduction was achieved by supplementing osmotic agents to the media. Plant responses to in vitro storage, genetic stability and field performance were the parameters used to evaluate the germplasm conservation conditions. Forty-nine treatments were applied, as the result of seven genotypes with seven media. After 12 months of storage, culture survival across genotypes ranged from 65% to 85% and all the media tested supported 100% regrowth. All genotypes regained their full growth potential within two months. Genetic stability between mother plants grown in the field and in vitro conserved plantlets at 6 and 12 months of storage was assessed by molecular markers to identify the most suitable storage media.Protocol suitability was validated by a field test using an approved list of plant descriptors for globe artichoke. Morphological data highlighted that the slight genetic instability detected by molecular markers did not affect significantly plants morphology and their agronomic traits.The results indicate that the minimal growth medium of choice for globe artichoke conservation is the one where the seven genotypes displayed phenotypes similar to the control, coupled with the lowest percentage of changes (2.43%) at a molecular level. As far as we know there are no published reports on in vitro conservation protocolfor globe artichoke applied to different genotypes and validated by an appropriate field test. © 2015 Elsevier B.V
Gauging the genetic changes occurring across globe artichoke micropropagation towards an appropriate variety registration and nursery production
No full textMicropropagation of globe artichoke is an alternative method for production of large-scale vegetative material, particularly for spring cultivars. In spite of the widespread use of in vitro propagated material both for artichoke large-scale commercial production and for germplasm preservation, there is a lack of information about the consequences of in vitro propagation on genetic stability of globe artichoke. In the present work leaves from mother plants grown in the field and from in vitro multiplicated shoots were analyzed over two years to determine genetic stability and to evaluate the influence of the number of subcultures on the generation of somaclonal variants. Genetic stability was assessed using ISSR and SSR molecular markers on four ecotypes and two lines derived by crosses. The primers used exhibited a varying ability to detect genetic variation as shown by their polymorphic information content (PIC) values. It was found that ISSRs can be applied effectively in the evaluation of genetic stability/variability, including in vitro, detected by an automated sequencer. The technique was effective in detecting changes occurring during the micropropagation process. Statistically significant differences were revealed among clones, i.e. there were clones accumulating a greater amount of changes while others showed a lower degree of changes during subculture. Nevertheless, the general trend of changes across the subculture was similar, reaching a maximum rate between the 2nd and 4th subcultures. These results are important to both the theoretical and practical points of view, for breeders in order to proceed for variety registration, and their implications are discussed. © 2013 Elsevier B.V
Distinct Effects of p19 RNA Silencing Suppressor on Small RNA Mediated Pathways in Plants
No full textRNA silencing is one of the main defense mechanisms employed by plants to fight viruses. In change, viruses have evolved silencing suppressor proteins to neutralize antiviral silencing. Since the endogenous and antiviral functions of RNA silencing pathway rely on common components, it was suggested that viral suppressors interfere with endogenous silencing pathway contributing to viral symptom development. In this work, we aimed to understand the effects of the tombusviral p19 suppressor on endogenous and antiviral silencing during genuine virus infection. We showed that ectopically expressed p19 sequesters endogenous small RNAs (sRNAs) in the absence, but not in the presence of virus infection. Our presented data question the generalized model in which the sequestration of endogenous sRNAs by the viral suppressor contributes to the viral symptom development. We further showed that p19 preferentially binds the perfectly paired ds-viral small interfering RNAs (vsiRNAs) but does not select based on their sequence or the type of the 5’ nucleotide. Finally, co-immunoprecipitation of sRNAs with AGO1 or AGO2 from virus-infected plants revealed that p19 specifically impairs vsiRNA loading into AGO1 but not AGO2. Our findings, coupled with the fact that p19-expressing wild type Cymbidium ringspot virus (CymRSV) overcomes the Nicotiana benthamiana silencing based defense killing the host, suggest that AGO1 is the main effector of antiviral silencing in this host-virus combination. © 2016 Kontra et al
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