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PLANT PHYSIOLOGY and MOLECULAR BIOLOGY
DiSAFA, University of Torino

Plant physiology and molecular biology

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Grapevine fruit ripening and stress biology

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Grapevine is the most widespread fruit crop worldwide and its fruits are rich in health-promoting flavonoids. They play essential roles in adaptation to environmental and biotic stress, and are important determinants of the quality of plant-derived foods because of their antioxidant and therapeutic properties. Most of the genes that allow flavonoid diversity are not known. We focus our research on the identification and regulation of anthocyanin decorating genes (methyl- and acyltransferases) in grapevine (V. vinifera L). Global change is affecting the exposure of grapes to abiotic and biotic stress, endangering yield and quality in the European traditional growing areas. We are identifying novel markers of resistance to drought stress, in particular microRNAs targeting genes involved in growth and stress resistance. Furthermore, we are involved in the identification of genes affected by flavescence dorée phytoplasma infection in field and in controlled conditions, with the aim of unravelling potential mechanisms inducing recovery from this very serious grape disease.

 Water transport in plants

Water moves through plants following apoplastic and symplastic routes and encounters a series of resistances. The sum of these resistances determines water transport rates, which in turn control water availability to the plant organs, and growth and survival of the plant. Resistances to water flow in roots, shoots and leaves are due to structural factors (transport across cell walls and membranes, xylem embolization) and are finely regulated.

We are interested in the effect of agronomic and environmental factors on shoot water conductivity in woody plants, particularly grapevine. We study how water stress and shoot positioning modify shoot hydraulic conductivity, in relation to hormonal signaling (auxin from the apex, ABA from the root). We perform plant water physiology measurements to assess water potential, gas exchange, sap flow and hydraulic conductivity. Furthermore we work on the role of membrane intrinsic proteins (MIPs) or aquaporins in cellular water transport. To this aim we are characterizing aquaporin genes of V. vinifera L., and their physiological function and expression pattern in grapevine. In addition, we have overexpressed the aquaporin VvPIP2;4N in grapevines to demonstrate its functions in watered and in droughted conditions.

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Dynamics and role of strigolactones in plant development under abiotic stress

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Strigolactones are a family of carotenoid-derived plant metabolites with a multitude of functions, both in the plant and in the biotic environment surrounding it. Structurally they all share an ABC-ring system connected via an enol-ether bridge to a butenolide ring named D. Exuded in soil, they stimulate seed germination of root-parasitic weeds; however their most prominent and recently discovered role is as hormones influencing whole-plant morphology and development, especially in response to stress. In the root, they are involved in the accommodation process for symbiotic N-fixing bacteria and mycorrhizal fungi, and they also stimulate hyphal branching in soil. Thus, strigolactones indirectly improve plant mineral nutrition, and because of their influence on plant morphology, they are key resource allocators in response to environmental changes - namely under limited water and nutrient availability. This strongly suggests the possibility that their manipulation, or at least a fine understanding of their biology, would allow to steer their metabolism to improve plant yield in stressful environments.

Our current research interests on the topic include strigolactone perception, role and metabolism under osmotic stress. We are working on the cell biology, molecular and structural details of perception by collaborating with organic chemists, crystallographers, and drug designers. We also aim at understanding what the local and systemic changes of strigolactone levels - that we observe in different organs of plants undergoing osmotic stress - mean for whole-plant hormonal balance (namely, in the cross-talk with abscisic acid). Finally, we are trying to feed our knowledge into crop management practices that will improve plant performances and yield under stress.med D. Exuded in soil, they stimulate seed germination of root-parasitic weeds; however their most prominent and recently discovered role is as hormones influencing whole-plant morphology and development, especially in response to stress. In the root, they are involved in the accommodation process for symbiotic N-fixing bacteria and mycorrhizal fungi, and they also stimulate hyphal branching in soil. Thus, strigolactones indirectly improve plant mineral nutrition, and because of their influence on plant morphology, they are key resource allocators in response to environmental changes - namely under limited water and nutrient availability. This strongly suggests the possibility that their manipulation, or at least a fine understanding of their biology, would allow to steer their metabolism to improve plant yield in stressful environments.

Research tools

Our research toolbox merges physiological, analytical, biochemical, and molecular tools. We assess physiological plant status by gas exchange, chlorophyll fluorimetry, conductance measurements. Analytical techniques such as HPLC-DAD and GC-MS are employed to measure concentrations of secondary metabolites and plant hormones. In vitro activity analysis of recombinant proteins is applied for characterization of enzymes. Targeted and non-targeted gene expression studies employ qRT-PCR and analysis of RNAseq outputs. Reverse genetic studies using custom transformed plant genotypes, and available Arabidopsis and tomato mutants, are performed in order to characterize gene function.

Research group

upload_schubert.gif Andrea Schubert: professor of Plant Physiology. His research interests include molecular and physiological aspects of water transport and water stress, stress-responsive sRNAs and gene regulation, and biosynthesis of flavonoids in grapevine. He is also concerned with the regulation of such pathways under condition of osmotic and biotic stress and with their implications in the optimization of plant growing and fruit processing techniques. Co-founder of Grape Srl and of Strigolab Srl.
upload_lovisolo.gif Claudio Lovisolo: associate Professor in Plant Physiology. He is an expert in plant ecophysiological studies and plant hydraulics and has experience in the isolation and functional characterization of plant water channels. His studies focus mainly on grapevine adaptation to abiotic stress and hormone (abscisic acid, strigolactone) signaling in droughted plants.
upload_cardinale.gif Francesca Cardinale: researcher in Plant Physiology. She has expertise in molecular plant physiology and pathology, biotechnology, stress signal transduction. Her current studies focus on strigolactones, with emphasis on cell type/organ specificity and long-range stress signalling, and on the receptor protein and downstream signalling events both in Arabidopsis thaliana and Lycopersicon esculentum. She is co-charter member of StrigoLab S.r.l. (www.strigolab.eu).
  Francesca Secchi: researcher in Plant Physiology. She has expertise in molecular plant physiology. Her current research focuses on whole woody plant water relations, sugar metabolism, structure and function of plant vascular network and abiotic plant stress biology.
upload_pagliarani.gif Chiara Pagliarani: post-Doc. She is a plant biotechnologist expert in molecular analyses of grapevine responses to environmental stress. Her research activities are focused on the characterization of stress-responsive small RNAs in diverse grapevine genotypes, and in the identification of transcripts affected by flavescence dorée infection in grapevine. She is co-charter member and CEO of Grape srl (www.grapesrl.it).
upload_visentin.gif Ivan Visentin: post-Doc. He is an expert in molecular biotechnology of plants and plant pathogens. He is currently investigating the molecular determinants of organ specificity in strigolactone metabolism, and strigolactone effect on abscisic acid metabolism, transport and sensitivity. He is co-charter member and CEO of StrigoLab S.r.l. (www.strigolab.eu).
upload_vitali.gif Marco Vitali: PhD. He has experience in gas exchange, chlorophyll fluorescence and leaf hydraulics measurements. His research field is grapevine ecophysiology, he investigates responses to climate change, pathological constraints, and to environmental stress.
upload_ferrero.gif Manuela Ferrero: PhD student. She is a plant biotechnologist, her activity is focused on the study of enzymes involved in the metabolism of Vitis vinifera secondary metabolites, which are important for their nutraceutical properties.

Prodotti della ricerca

Hugueney Ph., Provenzano S., Verriès C., Ferrandino A., Meudec E., Batelli G., Mrdinoglu D., Cheynier V., Schubert A., Ageorges A.
A novel cation-dependent O-methyltransferase involved in anthocyanin methylation in grapevine
http://hdl.handle.net/2318/73469

Carra A, Mica E, Gambino G, Pindo P, Moser C, Pè M, Schubert A
Cloning and characterization of small non-coding RNAs from grape
http://hdl.handle.net/2318/58934

..... (under updating)

 

 

Tag: plant physiology, molecular biology

Ultimo aggiornamento: 27/12/2016 17:20