<i>Medicago truncatula</i> functional genomics: an invaluable resource for studies on agriculture sustainability

Legume functional genomics has moved many steps forward in the last two decades thanks to the improvement of genomics technologies and to the efforts of the research community. Tools for functional genomics studies are now available in Lotus japonicus, Medicago truncatula and soybean. In this chapter we focus on M.truncatula, as a model species for forage legumes, on the main achievements obtained due to the reported resources and on the future perspectives for the study of gene function in this species

Medicago truncatula Functional Genomics - An Invaluable Resource for Studies on Agriculture Sustainability

© 2012 Panara et al., licensee InTech. This is an open access chapter distributed under the terms of th

EFFECTS OF SUPPORT STRUCTURE DYNAMICS ON CENTRIFUGAL COMPRESSOR ROTOR RESPONSE

LectureAccurate modeling of complicated dynamic phenomena characterizing rotating machineries represents a critical aspect in the rotor dynamic field. A correct prediction of rotor behavior is fundamental to identify safe operating conditions avoiding unstable operating range that may lead to erroneous project solution or possible unwanted consequences for the plant. Considering generic rotating machineries as mainly partitioned in four components (rotors, bearings, stator and supporting structure), most research activities have been addressed so far with strong focus more on the single components rather than on the whole system assembly. The importance of a combined analysis of rotors and elastic supporting structure (Kruger 2013) arises with the continuous development of turbo machinery applications, in particular in the Oil & Gas field, where a wide variety of solutions, such as off-shore installations or modularized turbo compression and turbo generator trains, lead to the need of a more complete study not only limited to the rotor-bearing system

EFFECTS OF SUPPORT STRUCTURE DYNAMICS ON CENTRIFUGAL COMPRESSOR ROTOR RESPONSE

LectureAccurate modeling of complicated dynamic phenomena characterizing rotating machineries represents a critical aspect in the rotor dynamic field. A correct prediction of rotor behavior is fundamental to identify safe operating conditions avoiding unstable operating range that may lead to erroneous project solution or possible unwanted consequences for the plant. Considering generic rotating machineries as mainly partitioned in four components (rotors, bearings, stator and supporting structure), most research activities have been addressed so far with strong focus more on the single components rather than on the whole system assembly. The importance of a combined analysis of rotors and elastic supporting structure (Kruger 2013) arises with the continuous development of turbo machinery applications, in particular in the Oil & Gas field, where a wide variety of solutions, such as off-shore installations or modularized turbo compression and turbo generator trains, lead to the need of a more complete study not only limited to the rotor-bearing system

An Italian functional genomic resource for Medicago truncatula

Background: Medicago truncatula is a model species for legumes. Its functional genomics have been considerably boosted in recent years due to initiatives based both in Europe and US. Collections of mutants are becoming increasingly available and this will help unravel the genetic control of important traits for many species of legumes. Findings: Our report is on the production of three complementary mutant collections of the model species Medicago truncatula produced in Italy in the frame of a national genomic initiative. Well established strategies were used: Tnt1 mutagenesis, TILLING and activation tagging. Both forward and reverse genetics screenings proved the efficiency of the mutagenesis approaches adopted, enabling the isolation of interesting mutants which are in course of characterization. We anticipate that the reported collections will be complementary to the recently established functional genomics tools developed for Medicago truncatula both in Europe and in the United States

Structural and immunological similarities between high molecular weight zinc ion-dependent p-nitrophenylphosphatase and fructose-1,6-bisphosphate aldolase from bovine liver

High molecular weight zinc ion-dependent acid p-nitrophenylphosphatase (HMW-ZnAPase) was purified from bovine liver to homogeneity as judged by native and sodium dodecyl sulfate polyacrylamide gel electrophoresis. The partial sequence of the purified enzyme electroblotted on PVDF membrane reveals a 95% sequence homology with human and bovine liver fructose-1,6-bisphosphate aldolase isozyme B (FALD B). FALD B was isolated from bovine liver using an affinity elution from phosphocellulose column. FALD B from bovine liver shows a native and subunit molecular weight that is indistinguishable from that of HMW-ZnAPase. In addition, an affinity purified antiserum raised in rabbits against purified HMW-ZnAPase cross-reacts with bovine liver FALD B and rabbit muscle isozymes. Despite these similarities, HMW-ZnAPase does not show FALD activity and bovine liver FALD does not display any zinc ion-p-nitrophenylphosphatase activity. These results suggested the existence of structural and immunological similarities between bovine liver HMW-ZnAPase and FALD B. Differences in some amino acid residues in enzyme activity indicate that they may be involved in different biochemical functions. © 2001 Elsevier Science B.V

Functional Characterization of MtrGSTF7, a Glutathione S-Transferase Essential for Anthocyanin Accumulation in Medicago truncatula

Flavonoids are essential compounds widespread in plants and exert many functions such as defence, definition of organ colour and protection against stresses. In Medicago truncatula, flavonoid biosynthesis and accumulation is finely regulated in terms of tissue specificity and induction by external factors, such as cold and other stresses. Among flavonoids, anthocyanin precursors are synthesised in the cytoplasm, transported to the tonoplast, then imported into the vacuole for further modifications and storage. In the present work, we functionally characterised MtrGSTF7, a phi-class glutathione S-transferase involved in anthocyanin transport to the tonoplast. The mtrgstf7 mutant completely lost the ability to accumulate anthocyanins in leaves both under control and anthocyanin inductive conditions. On the contrary, this mutant showed an increase in the levels of soluble proanthocyanidins (Pas) in their seeds with respect to the wild type. By complementation and expression data analysis, we showed that, differently from A. thaliana and similarly to V. vinifera, transport of anthocyanin and proanthocyanidins is likely carried out by different GSTs belonging to the phi-class. Such functional diversification likely results from the plant need to finely tune the accumulation of diverse classes of flavonoids according to the target organs and developmental stages

Genome-Wide Identification of Histone Modification Gene Families in the Model Legume <i>Medicago truncatula</i> and Their Expression Analysis in Nodules

Histone methylation and acetylation are key processes in the epigenetic regulation of plant growth, development, and responses to environmental stimuli. The genes encoding for the enzymes that are responsible for these chromatin post-translational modifications, referred to as histone modification genes (HMGs), have been poorly investigated in Leguminosae species, despite their importance for establishment and activity of nitrogen-fixing nodules. In silico analysis of Medicago truncatula HMGs identified 81 histone methyltransferases, 46 histone demethylases, 64 histone acetyltransferases, and 15 histone deacetylases. MtHMGs were analyzed for their structure and domain composition, and some combinations that were not yet reported in other plant species were identified. Genes have been retrieved from M. truncatula A17 and R108 genotypes as well as M. sativa CADL and Zhongmu No.1; the gene number and distribution were compared with Arabidopsis thaliana. Furthermore, by analyzing the expression data that were obtained at various developmental stages and in different zones of nitrogen-fixing nodules, we identified MtHMG loci that could be involved in nodule development and function. This work sets a reference for HMG genomic organization in legumes which will be useful for functional investigation that is aimed at elucidating HMGs involvement in nodule development and symbiotic nitrogen fixation

Comparative transcriptomics between high and low rubber producing Taraxacum kok-saghyz R. plants

Abstract Background Taraxacum kok-saghyz R. (Tks) is a promising alternative species to Hevea brasiliensis for production of high quality natural rubber (NR). A comparative transcriptome analysis of plants with differential production of NR will contribute to elucidate which genes are involved in the synthesis, regulation and accumulation of this natural polymer and could help to develop Tks into a rubber crop. Results We measured rubber content in the latex of 90 individual Tks plants from 9 accessions, observing a high degree of variability. We carried out de novo root transcriptome sequencing, assembly, annotation and comparison of gene expression of plants with the lower (LR plants) and the higher rubber content (HR plants). The transcriptome analysis also included one plant that did not expel latex, in principle depleted of latex transcripts. Moreover, the transcription of some genes well known to play a major role in rubber biosynthesis, was probed by qRT-PCR. Our analysis showed a high modulation of genes involved in the synthesis of NR between LR and HR plants, and evidenced that genes involved in sesquiterpenoids, monoterpenoids and phenylpropanoid biosynthesis are upregulated in LR plants. Conclusions Our results show that a higher amount of rubber in the latex in HR plants is positively correlated with high expression levels of a number of genes directly involved in rubber synthesis showing that NR production is highly controlled at transcriptional level. On the other hand, lower amounts of rubber in LR plants is related with higher expression of genes involved in the synthesis of other secondary metabolites that, we hypothesize, may compete towards NR biosynthesis. This dataset represents a fundamental genomic resource for the study of Tks and the comprehension of the synthesis of NR and other biochemically and pharmacologically relevant compounds in the Taraxacum genus

Modulation of Aspirin-Insensitive Eicosanoid Biosynthesis by 6-Methylprednisolone in Unstable Angina

Background—The evidence that inflammation plays a pivotal role in the pathophysiology of acute coronary syndromes prompted us to investigate the effects of glucocorticoid treatment on leukotriene (LT) C4and thromboxane (TX) A2biosynthesis in unstable angina.Methods and Results—Urinary LTE4and 11-dehydro-TXB2were significantly higher in 12 patients with unstable angina than in 12 patients with stable angina and 12 patients with nonischemic chest pain. Furthermore, we randomized the unstable angina patients to receive intravenous 6-methylprednisolone (6-MP; 1 mg/kg BID for 2 days) or matching placebo and collected 12 consecutive 6-hour urine samples before and during the infusions. LTE4excretion showed a time-dependent decrease in the 6-MP group but did not decrease during placebo. Furthermore, during myocardial ischemia, LTE4was significantly higher before 6-MP infusion than during steroid therapy. In contrast, 11-dehydro-TXB2did not differ significantly during 6-MP versus placebo. Myocardial ischemia elicited by stress test in the stable angina patients was not accompanied by any change in LTE4and 11-dehydro-TXB2, thus ruling out a role of ischemia per se in the induction of increased eicosanoid production.Conclusions—Increased production of vasoactive LT and TX may occur in unstable angina despite conventional antithrombotic and antianginal treatment. Glucocorticoids can suppress LTC4biosynthesis in the short term and may provide an interesting tool to explore the pathophysiological significance of inflammatory cell activation in this setting