Silvia Fornale

CRAG Centre for Research in Agricultural Genomics | CRAG · Department of Molecular Genetics

The plant cell wall is a plastic structure of variable composition that constitutes the first line of defense against environmental challenges. Lodging and drought are two stressful conditions that severely impact on maize yield. In a previous work, we characterized the cell walls of two maize inbreds susceptible (EA2024) or resistant (B73) to stal...

Maize (Zea mays L.) is one of the most important crops worldwide in terms of production, providing a huge reservoir of biomass for being used as biofuel and/or animal feedstock. In this respect, it has been widely shown that stover assimilation and saccharification yield are compromised by the recalcitrance of maize biomass. This matter can be appr...

Lodging is one of the causes of maize (Zea mays L.) production losses worldwide and, at least, the resistance to stalk lodging has been positively correlated with stalk strength. In order to elucidate the putative relationship between cell wall, stalk strength and lodging resistance, twelve maize inbreds varying in rind penetration strength and lod...

Caffeoyl Coenzyme A 3-O-Methyltransferase (CCoAOMT) and Caffeic acid-O-Methyltransferase (COMT) are key enzymes in the biosynthesis of coniferyl and sinapyl alcohols, the precursors of guaiacyl (G) and syringyl (S) lignin subunits. The function of these enzymes was characterised in single and double mutant maize plants. In this work, we determined...

Maize lodging represents a significant loss in grain yield. Several studies indicated that the physico-chemical properties of the secondary cell wall are key factors in determining the degree of stalk strength in different maize varieties. Secondary cell wall is a dynamic structure mainly composed of lignin, cellulose and hemicelluloses. However, t...

Lignin is an essential polymer in vascular plants that plays key structural roles in vessels and fibers. Lignification is induced by external inputs such as wounding, but the molecular mechanisms that link this stress to lignification remain largely unknown. In this work, we provide evidence that three maize (Zea mays) lignin repressors, MYB11, MYB...

Coumarate 3-hydroxylase (C3H) catalyzes a key step of the synthesis of the two main lignin subunits, guaiacyl (G) and syringyl (S) in dicotyledonous species. As no functional data are available in regards to this enzyme in monocotyledonous species, we generated C3H1 knock-down maize plants. The results obtained indicate that C3H1 participates in li...

The phenylpropanoid metabolic pathway provides a wide variety of essential compounds for plants. Together with sinapate esters, in Brassicaceae species, flavonoids play an important role in protecting plants against ultraviolet irradiation. Results: In this work we have characterized the Arabidopsis thaliana AtMYB7, the closest homolog of AtMYB4 an...

Cinnamyl alcohol dehydrogenase (CAD) is a key enzyme involved in the last step of monolignol biosynthesis. The effect of CAD down-regulation on lignin production was investigated through a transgenic approach in maize. Transgenic CAD-RNAi plants show a different degree of enzymatic reduction depending on the analyzed tissue and show alterations in...

Few regulators of phenylpropanoids have been identified in monocots having potential as biofuel crops. Here we demonstrate the role of the maize (Zea mays) R2R3-MYB factor ZmMYB31 in the control of the phenylpropanoid pathway. We determined its in vitro consensus DNA-binding sequence as ACC(T)/(A) ACC, and chromatin immunoprecipitation (ChIP) estab...

Few regulators of phenylpropanoids have been identified in monocots having potential as biofuel crops. Here we demonstrate the role of the maize (Zea mays) R2R3-MYB factor ZmMYB31 in the control of the phenylpropanoid pathway. We determined its in vitro consensus DNA-binding sequence as ACC T / A ACC, and chromatin immunoprecipitation (ChIP) establ...

The involvement of the maize ZmMYB42 R2R3-MYB factor in the phenylpropanoid pathway and cell wall structure and composition was investigated by overexpression in Arabidopsis thaliana. ZmMYB42 down-regulates several genes of the lignin pathway and this effect reduces the lignin content in all lignified tissues. In addition, ZmMYB42 plants generate a...

Xyloglucan endotransglucosylase/hydrolases (XTHs; EC 2.4.1.207 and/or EC 3.2.1.151) are enzymes involved in the modification of cell wall structure by cleaving and, often, also re-joining xyloglucan molecules in primary plant cell walls. Using a pool of antibodies raised against an enriched cell wall protein fraction, a new XTH cDNA in maize, ZmXTH...

The maize (Zea mays L.) caffeic acid O-methyl-transferase (COMT) is a key enzyme in the biosynthesis of lignin. In this work we have characterized the involvement of COMT in the lignification process through the study of the molecular mechanisms involved in its regulation. The examination of the maize COMT gene promoter revealed a putative ACIII bo...

In the present study we analysed polyamine metabolism in Arabidopsis thaliana (ecotype Columbia) rosette leaves collected at vegetative and reproductive stages from plants germinated and grown under increasing salt stress (0-75 mM NaCl) conditions. The expression level of the different isoforms of polyamine biosynthetic enzymes was analysed by reve...

Plant laccases are enzymes that have been proposed to participate in the last step of lignin biosynthesis. The polymerisation event remains still much unknown, implicating other enzymes such as peroxidases. To gain more insight in how this polymerisation process takes place in maize, we isolated by differential screening of an elongation maize root...

Here the effect of jasmonic acid, methyljasmonate and Na-orthovanadate on the production of resveratrol was studied in Vitis vinifera cv. Barbera cell suspension cultures. Na-orthovanadate at 0.1 mm and 1 mm concentration was efficient in promoting the production and/or accumulation and release in the culture medium of cis-resveratrol while trans-r...

Transgenic tobacco plants overexpressing the Datura stramonium spermidine synthase (EC 2.5.1.16) cDNA were produced in order to understand the role of this gene in the polyamine metabolism and in particular in affecting spermidine endogenous levels. All the analysed transgenic clones displayed a high Level of overexpression of the exogenous cDNA wi...

In this work we studied putative ornithine decarboxylase activity (ODC, EC 4.1.1.17) in leaves of Arabidopsis thaliana L. (ecotype Columbia) plants at non-flowering stage (about 21 d of culture). Putative ODC activity was higher in the particulate than in the soluble fraction and activity was pH-dependent, increasing linearly with the pH. Inclusion...

Summary • Polyamines have been suggested to counteract oxidative damage in plants. Here, we present a detailed analysis of polyamine accumulation and its relationship to photosynthetic parameters in two tobacco (Nicotiana tabacum) cultivars (ozone-sensitive Bel W3 and ozone-tolerant Bel B) after a single ozone pulse and after a 1-month exposure in...

Putrescine:SAM N-methyltransferase (PMT) catalyses the N-methylation of the diamine putrescine to form N-methylputrescine, the first specific precursor of both tropane and pyridine-type alkaloids, which are present together in the roots of Duboisia plants. The pmt gene of Nicotiana tabacum was placed under the regulation of the CaMV 35S promoter an...

Taxol transport in Taxus baccata L. cell suspension cultures was studied using 〚14C〛-taxol as a tracer. The time course of uptake showed a saturable absorption that reached a maximum within 20 min. The uptake depended on its exogenous concentration and its accumulation was highly stimulated in the presence of 10–15 μM exogenous taxol. The absorbed...

Endogenous polyamine content of the ectomycorrhizal fungus Paxillus involutus, as well as the activity of its biosynthetic enzymes in relation to mycelia ageing were investigated in this work. Polyamines in free, PCA-soluble and insoluble conjugated forms, are present in Paxillus involutus mycelia in relatively high amounts and the ratio of putresc...

 Jasmonic acid (JA) and its methyl ester (MeJA) at concentrations ranging from 0.001 to 10 μM provoked large increases in methylputrescine levels in normal and hairy roots of Hyoscyamus muticus L.; generally, levels of free putrescine and perchloric acid-soluble conjugated putrescine, spermidine and spermine also increased dramatically. More 14C-pu...

In this work, we have investigated polyamine levels (free and conjugated), activities and regulation of biosynthetic enzymes in different organs of Arabidopsis thaliana L. (ecotype Columbia) wild-type. When plants were grown at 0.5 mM spermidine, a different morphology was observed, with shorter stalks and darker green leaves. Spermidine-treated pl...

Inoculation of leaf sections of tobacco, Duboisia hybrid and Datura metel Solanaceae plants with A4 strain of Agrobacterium rhizogenes, induced transformed roots with the capacity to produce putrescine-derived alkaloids. In general, the hairy roots obtained showed two morphologies: typical hairy roots with high capacity to produce alkaloids and cal...

Polyamine content and enzyme activities in the biosynthetic and degradative pathways of polyamine metabolism were investigated in sieve-tube sap, xylem sap and tissues of seedlings and adult plants of Ricinus communis L. Polyamines were present in tissues and translocation fluids of both seedlings and adult plants in relatively high amounts. Only f...