OeBAS and CYP716C67 catalyze the biosynthesis of health-beneficial triterpenoids in olive (Olea europaea) fruits.

The bioactive properties of olive (Olea europaea) fruits and olive oil are largely attributed to terpenoid compounds, including diverse triterpenoids such as oleanolic, maslinic and ursolic acids, erythrodiol, and uvaol. They have applications in the agri-food, cosmetics, and pharmaceutical industries. Some key steps involved in the biosynthesis of these compounds are still unknown.

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

Flavonoids are essential compounds widespread in plants and exert many functions such as defence, definition of organ colour and protection against stresses. In , 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.

Genome-Wide Identification of Histone Modification Gene Families in the Model Legume 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 species, despite their importance for establishment and activity of nitrogen-fixing nodules. In silico analysis of HMGs identified 81 histone methyltransferases, 46 histone demethylases, 64 histone acetyltransferases, and 15 histone deacetylases.

Two bi-functional cytochrome P450 CYP72 enzymes from olive (Olea europaea) catalyze the oxidative C-C bond cleavage in the biosynthesis of secoxy-iridoids - flavor and quality determinants in olive oil.

Olive (Olea europaea) is an important crop in Europe, with high cultural, economic and nutritional significance. Olive oil flavor and quality depend on phenolic secoiridoids, but the biosynthetic pathway of these iridoids remains largely uncharacterized. We discovered two bifunctional cytochrome P450 enzymes, catalyzing the rare oxidative C-C bond cleavage of 7-epi-loganin to produce oleoside methyl ester (OeOMES) and secoxyloganin (OeSXS), both through a ketologanin intermediary.

Metabolic and transcriptional changes associated with the use of Ascophyllum nodosum extracts as tools to improve the quality of wine grapes (Vitis vinifera cv. Sangiovese) and their tolerance to biotic stress.

Background: Recent studies report that Ascophyllum nodosum extracts, once applied on the canopy of different crops, deliver positive effects, increasing yield, inducing tolerance to biotic stress, and improving the quality of products. However, the mechanisms of action are still unclear. In this research, vines subjected to multiple foliar applications of an A.

T-DNA Insertional Mutagenesis and Activation Tagging in Medicago truncatula.

The development of plant genetic transformation techniques has greatly enhanced our capacity to investigate and understand gene function. Since T-DNA constructs insert randomly in genomes, in principle, it is possible to construct a population of individuals harboring one or more T-DNA inserted in any region of the genome. Such populations can be screened following two approaches: (1) given a mutant phenotype, one could find the gene subtending the phenotypic alteration (forward approach), or (2) given a gene of interest, one could identify the phenotypic effect of its expression perturbation (reverse approach).

An apomixis-linked ORC3-like pseudogene is associated with silencing of its functional homolog in apomictic Paspalum simplex.

Apomixis in plants consists of asexual reproduction by seeds. Here we characterized at structural and functional levels an apomixis-linked sequence of Paspalum simplex homologous to subunit 3 of the ORIGIN RECOGNITION COMPLEX (ORC3). ORC is a multiprotein complex which controls DNA replication and cell differentiation in eukaryotes.

CYP72A67 Catalyzes a Key Oxidative Step in Medicago truncatula Hemolytic Saponin Biosynthesis.

In the Medicago genus, triterpenic saponins are bioactive secondary metabolites constitutively synthesized in the aerial and subterranean parts of plants via the isoprenoid pathway. Exploitation of saponins as pharmaceutics, agrochemicals and in the food and cosmetic industries has raised interest in identifying the enzymes involved in their synthesis. We have identified a cytochrome P450 (CYP72A67) involved in hemolytic sapogenin biosynthesis by a reverse genetic TILLING approach in a Medicago truncatula ethylmethanesulfonate (EMS) mutagenized collection.

Reverse genetics in Medicago truncatula using a TILLING mutant collection.

Medicago truncatula is one of the model species for legume molecular genetics. In the last decade different types of mutant populations have been created in this species that can be screened by forward and reverse-genetic approaches to identify and functionally characterize genes of interest. TILLING is a reverse-genetic method combining random chemical mutagenesis and a PCR-based screen to identify point mutations in regions of interest.

Involvement of protein kinases and calcium in the NO-signalling cascade for defence-gene induction in ozonated tobacco plants.

This study analyses the signalling pathways triggered by nitric oxide (NO) in response to ozone (O(3)) fumigation of tobacco plants, with particular attention to protein kinase cascades and free cytosolic Ca(2+) in defence-gene activation. NO was visualized with the NO probe DAF-FM. Using a pharmacological approach, the effects of different inhibitors on the expression profiles of NO-dependent defence genes were monitored using RT-PCR.

Medicago truncatula CYP716A12 is a multifunctional oxidase involved in the biosynthesis of hemolytic saponins.

Saponins, a group of glycosidic compounds present in several plant species, have aglycone moieties that are formed using triterpenoid or steroidal skeletons. In spite of their importance as antimicrobial compounds and their possible benefits for human health, knowledge of the genetic control of saponin biosynthesis is still poorly understood. In the Medicago genus, the hemolytic activity of saponins is related to the nature of their aglycone moieties.

The Arabidopsis thaliana cysteine-rich receptor-like kinase CRK20 modulates host responses to Pseudomonas syringae pv. tomato DC3000 infection.

In plants, the cysteine-rich repeat kinases (CRKs) are a sub-family of receptor-like protein kinases that contain the DUF26 motif in their extracellular domains. It has been shown that in Arabidopsis thaliana, CRK20 is transcriptionally induced by pathogens, salicylic acid and ozone (O(3)). However, its role in responses to biotic and abiotic stress remains to be elucidated.

Specific expression of apomixis-linked alleles revealed by comparative transcriptomic analysis of sexual and apomictic Paspalum simplex Morong flowers.

Apomixis is defined as clonal reproduction by seed. A comparative transcriptomic analysis was undertaken between apomictic and sexual genotypes of Paspalum simplex Morong to identify apomixis-related polymorphisms at the level of mRNA. cDNA-AFLP (amplified fragment length polymorphism) profiling of apomictic and sexual flowers at several stages of development yielded 202 amplicons that showed several kinds of expression specificities.

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.

Do pathogen-specific defense mechanisms contribute to wound-induced resistance in tomato?

A network of shared intermediates/components and/or common molecular outputs in biotic and abiotic stress signaling has long been known, but the possibility of effective influence between differently triggered stresses (co-protection) is less studied. Recent observations show that wounding induces transient protection in tomato (Solanum lycopersicum L.) to four pathogens with a range of lifestyles, locally and systemically.

Wounding induces resistance to pathogens with different lifestyles in tomato: role of ethylene in cross-protection.

Many reports point to the existence of a network of regulatory signalling occurring in plants during the interaction with micro-organisms (biotic stress) and abiotic stresses such as wounding. However, the focus is on shared intermediates/components and/or common molecular outputs in differently triggered signalling pathways, and not on the degree and modes of effective influence between abiotic and biotic stresses nor the range of true plant-pathogen interactions open to such influence. We report on local and systemic wound-induced protection in tomato (Solanum lycopersicum L.

Delay of leaf senescence in Medicago sativa transformed with the ipt gene controlled by the senescence-specific promoter SAG12.

We report the successfull delay of leaf senescence in Medicago sativa. A highly regenerable clone of alfalfa was transformed with the construct SAG12-IPT, an approach that has already proved efficient in other crops. Several independent transformants were obtained as determined by Southern analysis and all the transformants expressed the transgene as measured by RT-PCR.

Molecular cytogenetics and DNA sequence analysis of an apomixis-linked BAC in Paspalum simplex reveal a non pericentromere location and partial microcolinearity with rice.

Apomixis in plants is a form of clonal reproduction through seeds. A BAC clone linked to apomictic reproduction in Paspalum simplex was used to locate the apomixis locus on meiotic chromosome preparations. Fluorescent in situ hybridisation revealed the existence of a single locus embedded in a heterochromatin-poor region not adjacent to the centromere.

Comparative mapping reveals partial conservation of synteny at the apomixis locus in Paspalum spp.

In plants, gametophytic apomixis is a form of asexual reproduction that leads to the formation of seed-derived offspring that are genetically identical to the mother plant. A common set of RFLP markers, including five rice anchor markers previously shown to be linked to apomixis in Paspalum simplex, were used to detect linkage with apomixis in P. notatum and P.

Plant regeneration from callus of apomictic and sexual lines of Paspalum simplex and RFLP analysis of regenerated plants.

Culture conditions have been established for the induction of callus from different explants of Paspalum simplex. Fast-growing calli were obtained from hypocotyls and roots excised from 5-day-old seedlings on culture medium containing 2,4-dichlorophenoxyacetic acid and kinetin. Rapid plant regeneration from both apomictic and sexual lines was achieved when the medium was supplemented with alpha-naphthaleneacetic acid and benzylaminopurine.

A topoisomerase II-dependent checkpoint in G2-phase plant cells can be bypassed by ectopic expression of mitotic cyclin B2.

DNA topoisomerase II is required for mitotic chromosome condensation and segregation. Here we characterize the effects of inhibiting DNA topoisomerase II activity in plant cells using the non-DNA damaging topoisomerase II inhibitor ICRF-193. We report that ICRF-193 abrogated chromosome condensation in cultured alfalfa (Medicago sativa L.

A novel tobacco mitogen-activated protein (MAP) kinase kinase, NtMEK1, activates the cell cycle-regulated p43Ntf6 MAP kinase.

Two-hybrid screening of a tobacco BY-2 cell suspension cDNA library using the p43(Ntf6) mitogen-activated protein (MAP) kinase as bait resulted in the isolation of a cDNA encoding a protein with features characteristic of a MAP kinase kinase (MEK), which has been called NtMEK1. Two-hybrid interaction analysis and pull-down experiments showed a physical interaction between NtMEK1 and the tobacco MAP kinases p43(Ntf6) and p45(Ntf4), but not p43(Ntf3). In kinase assays NtMEK1 preferentially phosphorylated p43(Ntf6).

Distinct osmo-sensing protein kinase pathways are involved in signalling moderate and severe hyper-osmotic stress.

Plant growth is severely affected by hyper-osmotic salt conditions. Although a number of salt-induced genes have been isolated, the sensing and signal transduction of salt stress is little understood. We provide evidence that alfalfa cells have two osmo-sensing protein kinase pathways that are able to distinguish between moderate and extreme hyper-osmotic conditions.

Regulation of cell division and the cytoskeleton by mitogen-activated protein kinases in higher plants.

The microtubule-associated protein 2 kinase (MAP2-kinase), now better known as mitogen-activated protein kinase (MAPK), was initially discovered in association with the cytoskeleton, and was later also implicated in cell division. The importance of mitogenic stimulation in plant development roused interest in finding the plant homologues of MAPKs. However, data on plant MAPKs in cell division are rather sparse and fragmentary.

A MAP kinase is activated late in plant mitosis and becomes localized to the plane of cell division.

In eukaryotes, mitogen-activated protein kinases (MAPKs) are part of signaling modules that transmit diverse stimuli, such as mitogens, developmental cues, or various stresses. Here, we report a novel alfalfa MAPK, Medicago MAP kinase 3 (MMK3). Using an MMK3-specific antibody, we detected the MMK3 protein and its associated activity only in dividing cells.