Progetto comune di ricerca

Manipolazione della qualità della luce per ottimizzare la fotosintesi e la produzione di metaboliti secondari di interesse per la protezione delle piante

Responsabili di progetto
Francesco Loreto, Violeta Borisova Velikova
Accordo
BULGARIA - BAS - Bulgarian Academy of Sciences
Bando
CNR/BAS 2013-2015
Dipartimento
Agroalimentare
Area tematica
Scienze bio-agroalimentari
Stato del progetto
Rinnovo
Relazione per il rinnovo
bilateral-bas-cnr-final-report-2010-2012-fl.pdf

Proposta di ricerca

Present state of knowledge in the field, significance and objectives of the joint research: Light is not only an essential energy source for plants but also an important signal, playing a key role  in plant development, biosynthesis of cell components and gene expression throughout the plant life cycle. Light in different spectral regions selectively activates different photoreceptors that induce highly overlapping sets of genes indicating presence of shared signaling components (Lin 2002). Of the various photoreceptors, the most intensively studied is a family of photoreversible red/far-red absorbing chromoproteins called phytochromes (review in Quail et al. 1995). Cryptochromes and phototropins are receptors for UV-A/blue light (Ahmad & Cashmore 1993). Spectral changes evoke different morphogenetic and photosynthetic responses, which can vary among different plant species (Shuerger et al. 1997). For example, red light plays the most important roles in the development of photosynthetic apparatus, is the main determinant of photosynthesis, and influences morphogenesis by light-induced transformations phytochrome system (Urbonaviciute et al. 2007). Blue light is also important for the plants by influencing chlorophyll formation, stomatal opening and photomorphogenesis (Heo et al. 2002). Green light has positive effect on biomass accumulation since it penetrates deeper in leaves and canopies than red and blue light (Terashima et al. 2009). Available studies on the effect of specific wavelengths on plants show that a variety of desired functional or structural changes can be obtained in crop plants by manipulating light quality and quantity (Massa et al. 2008, Pinho 2008). Illumination with specific narrow-band light can lead to modified sugar content (Urbonaviciute et al. 2007), and altered nitrate reductase activity and nitrogen content in the leaves (Pinho 2008). Antioxidant activity, the content of phenols, vitamins, flavonoids, antocyanins, tannins and other secondary metabolites can be manipulated depending on light wavelengths or wavelength ratios (Tegelberg et al. 2004). The possibility of increasing secondary metabolite concentrations by manipulating light quality  is also of increasing interest for human nutrition (Schijlen et al. 2006, Dorais et al. 2008). Light also affects the synthesis and emission of biogenic volatile organic compounds (BVOCs), especially isoprenoids, by plants (Peñuelas & Llusià 2001). BVOCs are predominantly emitted from leaves. They are involved in indirect plant defense against insects (Turlings et al. 1990), pollinator attraction (Reinhard et al. 2004), plant–plant communication (Arimura et al. 2000, Ton et al. 2007, Shulaev et al. 1997), plant–pathogen interactions (Arimura et al. 2000), reactive oxygen species removal (Loreto & Velikova 2001), thermotolerance (Sharkey et al. 2001) and other environmental stress adaptations (Dudareva et al. 2006). Many studies demonstrated that the emissions of isoprenoids are affected by abiotic and biotic stresses, being related to plant protection (Velikova 2008, Dicke & Baldwin 2010, Holopainen & Gershenzon 2010, Loreto & Schnitzler 2010). The main volatile isoprenoid emitted is the hemiterpene isoprene. Plants can emit as isoprene 0.5-2% of the carbon fixed photosynthetically, and a much higher percentage when leaves are stressed and photosynthesis is inhibited (Loreto and Schnitzler 2010). Light intensity is one of the best described external factor controlling BVOC emissions (Kesselmeier et al. 1996, Loreto et al. 1996, Llusià and Peñuelas 2000). Isoprene emission, in particular, is triggered by light, as it is dependent on photosynthesis (Sharkey & Yeh 2001). Generally, the emission of isoprene responds to light similar to photosynthesis, but does not saturate at similar light intensities, a feature that has not been understood so far (Harley et al. 1994, Monson et al. 1995, Sharkey & Loreto 1993). Light quality could affect the profile of BVOCs emitted, altering the BVOC-driven plant-herbivores interactions, e.g. higher FR/R ratios increase the amount of terpenoids attracting insects (Kasperbauer 2004, Schoonhoven et al. 2006). Here it is hypothesized that by manipulating the spectral composition of the light, isoprenoid emissions from plants can be enhanced, in order to improve plant defense against different stress stimuli.  In order to test this idea, innovative industrial technologies will be applied. In particular, studies on light quality are now available thanks to rapidly developing technology of high-quality, high-output light emitting diodes (LED). The main advantage of using LEDs for plants is the possibility of selecting the peak wavelength emission that most closely matches the absorption peak of a selected photoreceptor. Additionally, narrow-band LEDs allow creating a specific spectral distribution. Other benefits are the low power consumption and the low need to dissipate heat in comparison to other light sources, and the consequent more efficient and simpler climatization of LED-illuminated growth chambers and cabinet. These features suggest LEDs will have an important commercial interest, and represent a basic component of future climatization technology.
Background of cooperation and envisaged results and benefit: A variety of desired functional or structural changes in plants, e.g. increasing photosynthesis, modulating plant morphogenesis, controlling the timing of physiological events, stimulating the plant defense system, can be obtained by manipulating light spectral composition (Moe et al. 2006, Roberts & Paul 2006). It is well established that the light quality is highly varying during the day and among the seasons; it depends on clouds, atmospheric clearness and uneven extinction throughout canopies, among the other factors. Since light is a factor triggering and controlling isoprenoid emissions from plants, understanding BVOC emission responses to light quality will allow manipulating hydrocarbon fluxes in the atmosphere, which in turn can influence the global atmospheric carbon budget and the oxidative potential of the troposphere. The work outlined in the proposal will clarify basic questions related to plant response / acclimation to light with different spectral composition, in terms of photosynthesis, BVOC emissions and stress resistance. The proposed research will extend understanding of the relationship between plant development stage, photosynthesis and volatile emissions. The finding may have poten­tial practical application enhancing plant protection through direct and indirect plant defense. Optimal light spectra from physiological and energy viewpoints will be suggested when using artificial lighting systems for plant growing. The collaboration between BAS and CNR on volatile isoprenoids has yielded so far important results. We have conducted collaborative research on the biological role of isoprene and protection against abiotic stresses (ozone, high temperature); on the effect of a future climate scenario - elevated CO2 and temperature and plant stress resistance mediated by volatile secondary metabolites; on the use of isoprenoid emitting species for phytoremediation. These studies led to the several join publications in referred top specialist international journals (Tree Physiology 25:1523-1532, 2005; Plant Cell and Environment 28:318-327, 2005; Functional Plant Biology 33:931-940, 2006; Plant Biology 10:55-64, 2008; Environmental Pollution 157:2629-26-37, 2009 and 159:1058-1066, 2011; Plant Physiology 157:905:916, 2011; Plant Signaling & Behavior 7:1-3, 2012). The BAS and CNR groups have jointly or separately presented recent achievements on some of the most important scientific conferences of the field (Gordon Conferences, European Plant Science Organization, European Science Foundation). The collaboration has also brought to successful participation to cooperation projects funded by the European Commission, FP7 Environment programme, and to an intensive activity of training and transfer of knowledge between the two organizations. The expertise and technical backgrounds in the participating Bulgarian and Italian laboratories are complementary, which warrants the project success. The research of the Bulgarian group is focused on plant physiology, biochemistry, and biophysics. The Bulgarian laboratory has novel facilities for plant cultivation at controlled environmental conditions, some of which will be central for the proposed experiments, and equipments for physiological, biochemical and biophysical studies at field and laboratory level. The Italian group has interdisciplinary, technical and scientific experience about ecophysiology and molecular ecology, focusing on adaptation to abiotic and biotic stressors exacerbated by climate change, and is specifically leading the field on emissions, fluxes, roles and impacts of BVOCs in plant protection against environmental stresses. The Italian laboratory has state-of-the-art mass spectrometry facilities, including a state-of-art high-throughput Proton Transfer Reaction-Time of Flight-Mass Spectrometer (PTR-TOF-MS) for the study of volatile metabolites. The Italian laboratory is also equipped with full instrumentation for the study in vivo and in vitro of plant metabolism and eco-physiology, plant growth facilities and experimental fields. Aside from achievement of the scientific objective of this project, ancillary expected benefits resulting from the cooperation will be (1) exchange of methodological experience in energy-efficient and innovative illumination devices for plant growth facilities, and state-of-the-art, high-throughput technologies enabling volatile compounds monitoring (PTR-TOF-MS); (2) training of young researchers; (2) publication of joint scientific papers, acknowledging BAS-CNR support.
References: Ahmad, Cashmore (1993) Nature 366:162–66; Arimura et al (2000) Nature 406:512–515; Chameides et al (1988) Science 241:1473-1475; Dicke, Baldwin (2010) Trends in Plant Sci 15:167-175; Dorais et al (2008) Phytochem Rev 7:231–250; Dudareva et al (2006) Crit Rev Plant Sci 25:417-440; Harley et al (1994) Plant Physiol 105:279–285; Heo, Lee (2002) Plant Growth Reg 38:225-230; Holopainen, Gershenzon (2010) Trends in Plant Sci 15:176-184; Kasperbauer, Loughrin (2004) Crop Sci 44:198-203; Kesselmeier et al (1996) Atmos Environ 30:1841-1850; Lin (2002) The Plant Cell S207-S225; Llusià, Peñuelas (2000) Amer J Bot 87:133-140; Loreto, Schnitzler (2010) Trends in Plant Sci 15:154-166; Loreto et al (1996) Plant Physiol 110:1317-1322; Loreto, Velikova (2001) Plant Physiol 127:1781–1787; Massa et al (2008) HortScience 43:1951–1956; Moe et al (2006) Acta Horticulturae 711: 35–42; Monson et al (1995) Atmos Environ 29:2989–3002; Peñuelas, Llusià (2001) Biol Plan 44:481–487; Pinho (2008) PhD Thesis; Quail et al (1995) Science 268:675–80; Reinhard (2004) Nature 427:411; Roberts, Paul (2006) New Phytol 170:677-699; Schijlen et al (2006) Plant Biotech J. 4:433–444; Schoonhoven et al (2006) Insect-Plant Biology. 2nd edn.; Sharkey, Loreto (1993) Oecologia 95:328–333; Sharkey, Yeh (2001) Annu Rev Plant Physiol Plant Mol Biol 52:407-4306; Sharkey et al (2001) Plant Physiol 125:2001–2006; Shuerger et al (1997) Ann Bot 79:273-282; Shulaev et al (1997) Nature 385:718–721; Tegelberg et al (2004) Plant, Cell Environ 27:1005–1013; Terashima et al (2009) Plant Cell Physiol 50: 684–697; Ton et al (2007) Plant J 49:16–26; Turlings et al (1990) Science 250:1251–1253; Unsicker et al (2009) Curr Opin Plant Biol 12:479–485; Urbonaviciute et al (2007) University of Agriculture Sodininkyste Ir Darzininkyste 26:157-165; Velikova (2008) J Plant Interactions 3:1-15

Obiettivi della ricerca

The main objective of the proposed project is to examine short-term and long-term effects of light with different spectral content on BVOC emissions from diverse plant species, and the possibility to  improve plant resistance and tolerance to abiotic stress by manipulating (enhancing) the emission.
The specific objectives include studying (1) the relationship between light quality – photosynthesis – BVOC emissions and (2) prospects for minimizing adverse high temperature effects by light quality / BVOC emission control.

Ultimo aggiornamento: 29/03/2024