G. Zocchi | Università degli Studi di Milano - State University of Milan (Italy) (original) (raw)

Papers by G. Zocchi

Drought affects grapevine production worldwide. To protect grapevine from water stress, an eco-fr... more Drought affects grapevine production worldwide. To protect grapevine from water stress, an eco-friendly approach was adopted, establishing a large microbial collection from root tissues and rhizosphere of different rootstocks from the vineyards of Le Fracce Farm in Oltrepo Pavese, an area in north Italy that experiences summer drought. Nine strains, endowed with multiple plant growth promoting activities, were assayed under greenhouse conditions on plants grown in the clay-rich soil of the vineyard of origin. Bacteria treated plantlets of SO4 and 420A rootstocks were exposed to water stress (50% of the field water capacity) for over 30 days. Water stress affected uninoculated control plants that presented alterations of physiological parameters, while grapevine plants treated with bacteria appeared healthier with 10-20% higher photosynthetic levels. Plant biomass after 30 days of growth under water stress was 20-40% higher in treated plants than the untreated controls. The data highlight the biotechnological potential of PGP bacteria for protecting grapevine from drought

Plant nutrition for …, 2005

Metabolic responses to Fe deficiency in soybean roots: are there different Strategy I mechanisms?... more Metabolic responses to Fe deficiency in soybean roots: are there different Strategy I mechanisms?/G. Zocchi, P. De Nisi, M. Dell'Orto, L. Espen, P. Marino Gallina.-In: Plant nutrition for food security, human health and environmental protection./CJ Li et al..-[sl]: ...

Egyptian Journal of Agricultural Research

This work was carried out in the Laboratory of tissue culture Arid Land Agriculture Research Unit... more This work was carried out in the Laboratory of tissue culture Arid Land Agriculture Research Unit (ALARU) Faculty of Agriculture Ain Shams University during the two autumn seasons of 2006 and 2008 in two separated experiments. First: Micropropagation of globe artichoke (Cynara scolymus L.).Second: Acclimatization of plantlets produced from tissue culture condition to the open field. First experiment: data cleared that there is a relationship between the size of shoot-tip and the percentage of survival regenerated and the time needed to regenerate shoots however increasing the size of shoot tip explants from 2 to 5 cm led to a gradual increase in both survival and regenerated shoot percentage. And at the same time reduce the number of days needed to configured healthy shoots. Culturing the shoot tips explants in the media containing the ascorbic acid or citric acid led to a reduction of browning percentage. Increasing the levels of both cytokinins (BA and Kn) from 2.5 to 10.0 mg/L was sufficient to enhance the capability of explants to produce more shoots especially at high level but unfortunately the highest level of both cytokinins (10.0 mg/L) led to obtain callus formation beside shoots production which is undesirable. There are relationship between number of subculture and rates of shoots productions. Increasing the number of subcultures till fifth times increased gradually the number of shoot production and decreased shoot length. IBA added to the media for rooting the regenerated shoots encouraged the root formation (number and length|) than IAA treatments. On the other side addition of activated charcoal to the nutrient media is very important for enhancement root formation. Concerning of the second experiment (acclimatization) data reported that culturing the plantlets produced from tissue culture in pots contained vermiculite either alone or in combination with other compounds gave the highest transplants survival percentage (60-90 %) than other substrate treatments.

Agriculture is facing an emerging request of food to satisfy the needs of an increasing world pop... more Agriculture is facing an emerging request of food to satisfy the needs of an increasing world population. Moreover, the increasing frequency of dry periods in many world regions, together with the problems associated with soil salinity and phytopatogen attacks, result in a reduction of crop productivity. A low impact strategy to improve crop productivity without extending agriculture surfaces and using agro-chemicals, is the association of plants with Plant Growth Promoting Bacteria (PGPB) able to stimulate plant growth and to reduce plant disease incidence. Here we show that PGPB isolated from the phytosphere in arid ecosystems can couteract water sress in plants in vivo. PGPB were isolated from olive tree, grapevine and pepper plants from arid and semi-arid regions of the Mediterranean basin. Testing in vitro the isolates for their plant growth promotion (PGP) activities under different stress conditions allowed to identify polyvalent isolates, i.e. those capable of expressing mul...

Vitamin K-like compounds are widely diffused in plants, but their role and function are still par... more Vitamin K-like compounds are widely diffused in plants, but their role and function are still partially unknown. Vitamin K1, phylloquinone, is largely present in thylacoid membranes as an electron carrier inside the PSI redox chain. More recently, it has been found that Vitamins K1 and K3 may also affect the plasmalemma-bound H + -ATPase and some redox proteins including b-type cytochromes. The antioxidant role of Vitamin K is also discussed.

Biochimica et Biophysica Acta (BBA) - Nucleic Acids and Protein Synthesis, 1975

Elongation factor EF1 was found in a low salt homogenate of wheat embryos, either in the 100 000 ... more Elongation factor EF1 was found in a low salt homogenate of wheat embryos, either in the 100 000 × g supernatant or in the ribosome pellet. The ribosome-linked EF1 (EF1R), detached by high salt washing, was purified to electrophoretical homogeneity and its molecular and functional properties compared to those of a purified high molecular weight species of EF1 obtained from cytoplasm (EF1H). The two forms are associations of different polypeptides having in common only the polypeptide which can form the ternary complex with aminoacyl-tRNA and GTP. Whereas EF1 a is able to fulfill all the EF1 functions, EF1H, incubated with ribosomes completely deprived of elongation factors, can catalyze the aminoacyl-tRNA binding to ribosomes, but, in the presence of EF2, forms only a very small amount of poly(Phe).

Frontiers in Plant Science, 2013

Iron uptake in dicots depends on their ability to induce a set of responses in root cells includi... more Iron uptake in dicots depends on their ability to induce a set of responses in root cells including rhizosphere acidification through H + extrusion and apoplastic Fe(III) reduction by Fe(III)-chelate reductase.These responses must be sustained by metabolic rearrangements aimed at providing the required NAD(P)H, ATP and H +. Previous results in Fe-deficient cucumber roots showed that high H + extrusion is accompanied by increased phosphoenolpyruvate carboxylase (PEPC) activity, involved in the cytosol pH-stat; moreover 31 P-NMR analysis revealed increased vacuolar pH and decreased vacuolar [inorganic phosphate (Pi)]. The opposite was found in soybean: low rhizosphere acidification, decreased PEPC activity, vacuole acidification, and increased vacuolar [Pi]. These findings, highlighting a different impact of the Fe deficiency responses on cytosolic pH in the two species, lead to hypothesize different roles for H + and Pi movements across the tonoplast in pH homeostasis. The role of vacuole in cytosolic pH-stat involves the vacuolar H +-ATPase (V-ATPase) and vacuolar H +-pyrophosphatase (V-PPase) activities, which generating the pH and ψ, mediate the transport of solutes, among which Pi, across the tonoplast. Fluxes of Pi itself in its two ionic forms, H 2 PO 4 − predominating in the vacuole and HPO 2 4 − in the cytosol, may be involved in pH homeostasis owing to its pH-dependent protonation/deprotonation reactions. Tonoplast enriched fractions were obtained from cucumber and soybean roots grown with or without Fe. Both V-ATPase and V-PPase activities were analyzed and the enrichment and localization of the corresponding proteins in root tissues were determined by Western blot and immunolocalization. V-ATPase did not change its activity and expression level in response to Fe starvation in both species. V-PPase showed a different behavior: in cucumber roots its activity and abundance were decreased, while in Fe-deficient soybean roots they were increased. The distinct role of the two H + pumps in Pi fluxes between cytoplasm and vacuole in Fe-deficient cucumber and soybean root cells is discussed.

Plant Physiology, 1982

Corn roots or washed corn root tissue exposed to cold shock absorb 20 to 24% more "Ca2" into a no... more Corn roots or washed corn root tissue exposed to cold shock absorb 20 to 24% more "Ca2" into a nonexchangeable phase than control roots. Addition to fusicoccin largely prevents this additional calcium influx. The results are discussed in relation to injury-induced changes in nmebrane permeability of root ceOl membranes.

Plant Biology, 2013

The contribution of antioxidant defence systems in different tolerance to direct and bicarbonate-... more The contribution of antioxidant defence systems in different tolerance to direct and bicarbonate-induced Fe deficiency was evaluated in two pea cultivars (Kelvedon, tolerant and Lincoln, susceptible). Fe deficiency enhanced lipid peroxidation and H2 O2 concentration in roots of both cultivars, particularly in the sensitive one grown under bicarbonate supply. The results obtained on antioxidant activities (SOD, CAT, POD) suggest that H2 O2 accumulation could be due to an overproduction of this ROS and, at the same time, to a poor capacity to detoxify it. Moreover, under bicarbonate supply the activity of POD isoforms was reduced only in the sensitive cultivar, while in the tolerant one a new isoform was detected, suggesting that POD activity might be an important contributor to pea tolerance to Fe deficiency. The presence of bicarbonate also resulted in stimulation of GR, MDHAR and DHAR activities, part of the ASC-GSH pathway, which was higher in the tolerant cultivar than in the sensitive one. Overall, while in the absence of Fe only slight differences were reported between the two cultivars, the adaptation of Kelvedon to the presence of bicarbonate seems to be related to its greater ability to enhance the antioxidant response at the root level.

Journal of Plant Physiology, 2012

The demand for iron in leguminous plants increases during symbiosis, as the metal is utilised for... more The demand for iron in leguminous plants increases during symbiosis, as the metal is utilised for the synthesis of various Fe-containing proteins in both plant and bacteroids. However, the acquisition of this micronutrient is problematic due to its low bioavailability at physiological pH under aerobic conditions. Induction of root Fe(III)-reductase activity is necessary for Fe uptake and can be coupled to the rhizosphere acidification capacity linked to the H+-ATPase activity. Fe uptake is related to the expression of a Fe2+ transporter (IRT1). In order to verify the possible role of nodules in the acquisition of Fe directly from the soil solution, the localization of H+-ATPase and IRT1 was carried out in common bean nodules by immuno-histochemical analysis. The results showed that these proteins were particularly abundant in the central nitrogen-fixing zone of nodules, around the periphery of infected and uninfected cells as well as in the vascular bundle of control nodules. Under Fe deficiency an over-accumulation of H+-ATPase and IRT1 proteins was observed especially around the cortex cells of nodules. The results obtained in this study suggest that the increase in these proteins is differentially localized in nodules of Fedeficient plants when compared to the Fe-sufficient condition and cast new light on the possible involvement of nodules in the direct acquisition of Fe from the nutrient solution. Abbreviations BMbacteroid membraneCZcortex zoneEx Cexternal cortexFC-Rferric chelate reductaseICinfected cellIn Cinternal cortexIRT1iron regulated transporter 1IZinfected zoneLHleghemoglobinNRnitrogenasePBMperibacteroid membranePBSperibacteroid spaceSsiderophoreUCuninfected cellVBvascular bundle Keywords Fe absorptionImmunodetectionIron transporterPhaseolus vulgarisSymbiosis

Journal of Plant Physiology, 2010

Iron deficiency affects the function of the respiratory chain, primarily at the complex I and com... more Iron deficiency affects the function of the respiratory chain, primarily at the complex I and complex II levels. Because plant mitochondria possess alternative NAD(P)H dehydrogenases located in the inner membrane, oxidizing NAD(P)H from both cytosol and matrix, we investigated these activities in mitochondria of Fe-deficient roots. External and internal NAD(P)H dehydrogenase activity increased in Fe-deficient mitochondria. Accordingly, NDB1 protein strongly accumulated, while NDA1 did not show differences in Fe-deficient roots. The data presented support, for the first time, the hypothesis that Fe deficiency induces the alternative NAD(P)H dehydrogenases, bypassing the impaired complex I.

Environmental Microbiology, 2014

This full text was downloaded from iris-Aperto: https://iris.unito.it/ Summary Although drought i... more This full text was downloaded from iris-Aperto: https://iris.unito.it/ Summary Although drought is an increasing problem in agriculture, the contribution of the root-associated bacterial microbiome to plant adaptation to water stress is poorly studied. We investigated if the culturable bacterial microbiome associated with five grapevine rootstocks and the grapevine cultivar Barbera may enhance plant growth under drought stress. Eight isolates, over 510 strains, were tested in vivo for their capacity to support grapevine growth under water stress. The selected strains exhibited a vast array of plant growth promoting (PGP) traits, and confocal microscopy observation of gfp-labelled Acinetobacter and Pseudomonas isolates showed their ability to adhere and colonize both the Arabidopsis and grapevine rhizoplane. Tests on pepper plants fertilized with the selected strains, under both optimal irrigation and drought conditions, showed that PGP activity was a stress-dependent and not a per se feature of the strains. The isolates were capable of increasing shoot and leaf biomass, shoot length, and photosynthetic activity of drought-challenged grapevines, with an enhanced effect in drought-sensitive rootstock. Three isolates were further assayed for PGP capacity under outdoor conditions, exhibiting the ability to increase grapevine root biomass. Overall, the results indicate that PGP bacteria contribute to improve plant adaptation to drought through a water stress-induced promotion ability. Introduction Drought is a major problem in agriculture worldwide. For example, Europe experienced an extreme drought event in 2003, exacerbated by high summer temperatures, which led to a dramatic reduction in primary productivity (Ciais et al., 2005; Palliotti et al., 2009; Olesen et al., 2011). With the predicted increase in reduced rainfall and heat events due to global warming, plant productivity in temperate regions is threatened; water scarcity may lead to reduced plant development, leaf wilting, unbalanced fruit composition and seed maturation (Ciais et al., 2005). Plants respond to dry conditions in several ways, including modification of root architecture (shallow versus deep rooting) and leaf shape. Such responses can differ between perennial trees and annual plants, such as cereals (Vandeleur et al., 2009; Alsina et al., 2011). The former can potentially increase their resistance to drought by increased architectural plasticity of the root system that can explore deeper parts of the soil, while the latter exhibit a more limited plasticity due to a shorter life cycle (Gambetta et al., 2013). From a community perspective, plants can even react through modification of the species composition in the biocoenosis, especially when there are long lasting episodes of climate change (Chaves et al., 2010). Irrigation supports plant growth during drought and is increasingly required even for plants that traditionally are not irrigated, such as grapevine in Northern Italy. In many wine-producing areas, vineyard irrigation is increasingly important to maintain wine yield and quality (Zhang et al., 2012). This is leading to aquifer overexploitation with increased depletion of groundwater, threatening future crop production (Gleeson et al., 2012; Scanlon et al., 2012). Thus, it is urgent to develop sustainable agricultural practices to support productivity, minimizing the threat to water resources. The beneficial microbiome associated with roots and plant tissues, including the so-called plant growth promoting (PGP) bacteria (Marasco et al., 2013a), can contribute to alleviate plant stress by a variety of mechanisms (Hayat et al., 2010; Mapelli et al., 2013). Among them, PGP bacteria can directly enhance micronutrient uptake and affect phytohormone homeostasis, or indirectly stimulate the plant immune system against phytopathogens (Balloi et al., 2010) and improve soil texture and structure (Mapelli et al., 2012). For instance, some PGP bacteria are endowed with the 1-aminocyclopropane-1-carboxylate (ACC) deaminase enzyme (ACCd) (Glick et al., 2007) that can cleave the plant ethylene precursor ACC, thereby lowering the level of ethylene in developing or stressed plants (Glick, 2004). Relatively little information is available concerning grapevine-associated bacteria, although some researches have shown that reproductive organs, including seeds, flowers and berries, can be densely colonized by an endophytic microbiome, including Pseudomonas, Burkholderia and Bacillus spp. (Compant et al., 2011). The endophyte Burkholderia phytofirmans strain PsJN was shown to colonize grapevine rhizosphere and spread to inflorescence tissues through the xylem (Compant et al., 2005; 2008). This beneficial endophyte has a role in the biocontrol of Botrytis cinerea and Pseudomonas syringae (Barka et al., 2002). Besides a priming activity, strain PsJN protects grapevines from chilling, both through scavenging activity against cold stress molecules and affecting plant carbohydrate metabolism (Barka et al., 2006; Fernandez et al., 2012; Theocharis et al., 2012). Despite being a powerful eco-friendly solution to plant growth impairment under adverse conditions, relatively limited attention has

Biologia plantarum, 2012

Cucumber (Cucumis sativus L.) is considered a model plant for the investigation of Fe deficiency ... more Cucumber (Cucumis sativus L.) is considered a model plant for the investigation of Fe deficiency responses, since it strongly exhibits typical strategy I, i.e. increased activities of Fe(III)-chelate reductase, H +-ATPase and iron regulated transporters. In this study, cDNA amplified fragment length polymorphism analysis was employed to identify genes differentially expressed in the root apex following Fe deficiency. The expression patterns of the most interesting transcript derived fragments were validated by semiquantitative reverse transcriptase-polymerase chain reaction. A set of new genes overexpressed under Fe deficiency, such as those coding for calmodulin, SNAP, TIM23 and V-PPase were identified. Furthermore, we also observed that calmodulin protein accumulated in Fe-deficient root apexes.

Journal of Experimental Botany, 2007

Iron deficiency responses were investigated in roots of soybean, a Strategy I plant species. Soyb... more Iron deficiency responses were investigated in roots of soybean, a Strategy I plant species. Soybean responds to iron deficiency by decreasing growth, both at the root and shoot level. Chlorotic symptoms in younger leaves were evident after a few days of iron deficiency, with chlorophyll content being dramatically decreased. Moreover, several important differences were found as compared with other species belonging to the same Strategy I. The main differences are (i) a lower capacity to acidify the hydroponic culture medium, that was also reflected by a lower H +-ATPase activity as determined in a plasma membrane-enriched fraction isolated from the roots; (ii) a drastically reduced activity of the phosphoenolpyruvate carboxylase enzyme; (iii) a decrease in both cytosolic and vacuolar pHs; (iv) an increase in the vacuolar phosphate concentration, and (v) an increased exudation of organic carbon, particularly citrate, phenolics, and amino acids. Apparently, in soybean roots, some of the responses to iron deficiency, such as the acidification of the rhizosphere and other related processes, do not occur or occur only at a lower degree. These results suggest that the biochemical mechanisms induced by this nutritional disorder are differently regulated in this plant. A possible role of inorganic phosphate in the balance of intracellular pHs is also discussed.