Ascorbate peroxidase and catalase activities and their genetic regulation in plants subjected to drought and salinity stresses

Hydrogen peroxide (H2O2), an important relatively stable non-radical reactive oxygen species (ROS) is produced by normal aerobic metabolism in plants. At low concentrations, H2O2 acts as a signal molecule involved in the regulation of specific biological/physiological processes (photosynthetic functions, cell cycle, growth and development, plant responses to biotic and abiotic stresses). Oxidative stress and eventual cell death in plants can be caused by excess H2O2 accumulation. Since stress factors provoke enhanced production of H2O2 in plants, severe damage to biomolecules can be possible due to elevated and non-metabolized cellular H2O2. Plants are endowed with H2O2-metabolizing enzymes such as catalases (CAT), ascorbate peroxidases (APX), some peroxiredoxins, glutathione/thioredoxin peroxidases, and glutathione sulfo-transferases. However, the most notably distinguished enzymes are CAT and APX since the former mainly occurs in peroxisomes and does not require a reductant for catalyzing a dismutation reaction. In particular, APX has a higher affinity for H2O2 and reduces it to H2O in chloroplasts, cytosol, mitochondria and peroxisomes, as well as in the apoplastic space, utilizing ascorbate as specific electron donor. Based on recent reports, this review highlights the role of H2O2 in plants experiencing water deficit and salinity and synthesizes major outcomes of studies on CAT and APX activity and genetic regulation in droughtand salt-stressed plants

“Il lato oscuro della valutazione”: La percezione della valutazione e dell’assessment in un contesto universitario

The aim of this contribution is to focus on the reasons for the rejection of evaluation practices in the field of higher education and to understand how this refusal is connected to the “mechanism of unveiling of the educational system” that the evaluation implements. It attempts to provide an interpretative framework regarding the perception of students (but also university professors) of evaluation practices adopted in the university context, proposing to give an explanation that, although provisional, can contribute to the understanding of the refusal that usually accompanies the evaluation, which becomes not only the spy of a malaise but also that of a malfunctioning of teaching.This perception is an intervening factor, often neglected, but important if we want to fully understand the “how, when and why” the learning and the meaning of teaching are realized,and if we want to reveal the reasoning behind the educational action system with which it is possible to clarify the logics that guide the management of the interventions by the teachers.L’obiettivo di questo contributo è quello di mettere a fuoco le ragioni legate al rifiuto delle pratiche valutative nel campo dell’istruzione superiore e di capire come tale rifiuto sia connesso al “meccanismo di svelamento del sistema didattico” che la valutazione mette in atto.Esso tenta di fornire un quadro interpretativo riguardante la percezione degli studenti (ma anche dei docenti universitari) delle pratiche di valutazione adottate in contesto universitario,proponendosi di dare una spiegazione che, seppur provvisoria, possa offrire un contributo alla comprensione del rifiuto che generalmente accompagna la valutazione, il quale diventa non solo la spia di un malessere ma anche quella di un cattivo funzionamento dell’insegnamento. Tale percezione è un fattore interveniente, spesso trascurato, ma importante se si vuolecomprendere appieno “il come, il quando e il perché” si realizzi l’apprendimento e il senso dell’insegnamento, nonché se si desideri svelare ragionamenti che stanno alla base del sistema d’azione didattico con i quali è possibile chiarire le logiche che guidano la gestione degli interventi da parte dei docenti

Abitudini e atteggiamenti degli studenti “con basso rendimento”: una ricerca osservativa sulle abilità di studio

The research examines the relationship between students with low academic performance and perceived efficacy study in two of the school year, and at the beginning and at the end, to see“at a distance” of twelve months in the absence of specific interventions triggered by the teachers what happens on the level of skills and attitudes towards the study. It was considered appropriate to conduct two surveys to monitor the spontaneous development of study skills in specific learning contexts and subjects with poor performance to better understand the role played by certain factors in the link between goals , habits, and attitudes and school failure in order to allow teachers in training to identify appropriate strategies to intervene in the teaching. The research is part of that strand of literature that sees the possibility of identifying the risk factors relating to the process of acquisition of study skills in students with low mastery and low academicsuccess attending the school in the second grade, regardless of the type of school in question, that have common traits and characteristics on which it appears necessary to intervenewith educationally appropriate training programs related to the study of strategic skills in in order to limit the phenomena of school leavers and drop-out.La ricerca esamina le relazioni tra studenti con basso rendimento scolastico ed efficienza percepita nello studio in due momenti dell’anno scolastico, all’inizio e ed alla fine, per verificare “adistanza” di dodici mesi in assenza di interventi specifici attivati dagli insegnanti cosa accade sul piano delle abilità e atteggiamenti verso lo studio. Si è ritenuto opportuno effettuare due rilevazioniper seguire l’evoluzione spontanea delle abilità di studio in specifici contesti formativi e su soggetti con scarso rendimento per meglio comprendere il ruolo rivestito da alcuni fattori nel legame tra obiettivi, abitudini e atteggiamenti ed insuccesso scolastico al fine di consentire ad insegnanti in formazione continua di individuare strategie opportune per intervenire in sede didattica. La ricerca si inserisce nell’ambito di quel filone di studi che vede la possibilità di individuare i fattori di rischio riguardanti il processo di acquisizione delle abilità di studio in studenti con bassa padronanza e scarso successo scolastico frequentanti la scuola superiore di secondogrado, che, indipendentemente dal tipo di scuola considerato, possiedono tratti e caratteristiche comuni sulle quali appare necessario intervenire didatticamente con adeguati interventiformativi relativi alle abilità strategiche di studio al fine di limitare i fenomeni di dispersione scolastica e di drop-out

Synergistic effect of Trichoderma and chitosan application in tomato for the control of Cucumber mosaic virus infection

Soil and plant environment is characterized by a wide range of microorganisms able to interact with host plants and, in some cases, to differentially induce susceptibility or resistance to pathogens. Plant viruses cause chlorosis and necrosis, so decreasing plant growth and productivity. Differently, many fungi are able to trigger a beneficial relationship with plants. Trichoderma spp. are endophytic symbionts able to modify plants metabolism, increasing nutrient uptake by plants and photosynthetic efficiency, and protecting them from pathogens. A biopolymer able to elicit plant-immunity is chitosan, derived by the deacetylation of chitin, a component of some fungal cell walls. Chitosan improves the host hypersensitive response by the expression of pathogenesis-related proteins and the synthesis of secondary metabolites. Trichoderma harzianum T-22 (T22) induces defense responses against Cucumber mosaic virus Fny (CMV) in Solanum lycopersicum. On this basis, the aim of this work was to determine if the combination T22-chitosan has an antiviral activity against CMV in tomato plants. Plant physiological parameters (gas exchange, chlorophyll content and fluorescence) were followed throughout the experiment. Furthermore, ELISA test was employed to detect CMV. Results indicate that plants treated with T22 and chitosan had a strong attenuation of viral load, a higher chlorophyll content and a better photosynthetic performance compared to the untreated plants. Further investigations are in progress to determine plant antioxidant responses. In conclusion, combined treatment based on T22 and chitosan represents a highly effective strategy against CMV, embracing the criteria of sustainable agricultural practice and public health protection

Response of Two Local Common Bean Ecotypes of “Fagioli di Sarconi” PGI (Phaseolus vulgaris L.) to Seed-Borne Pathogens and Environmental Change

Among foods protected by the European Union with the PGI (Protected Geographical Indication) mark, several ecotypes of “Fagioli di Sarconi” common beans, typical legumes of Basilicata Region, are included. This work aimed to conduct a survey of seed-borne pathogens isolated from “Ciuoto” and “Cannellino rosso”, ecotypes of “Fagioli di Sarconi” common beans, in two years and cultivation areas of the National Park of the Agri Valley, for identifying resistant and climatic changes well-adapted genotypes. Three validated methods were used for the seed-borne pathogens screening. Eighteen fungi were differently found for ecotype and year of observation by the washing test. Saprophyte contaminants pathogens isolated and detected by the blotter test were strongly reduced by 1% sodium hypochlorite treatment. Using the between paper test, specific for detecting Colletotrichum lindemuthianum, the presence of this pathogen for both ecotypes, years and cultivation areas, and also some bacteria were individuated. Therefore, area-, environment- and ecotype-dependent differences were revealed, probably also caused by a different polyphenolic content and thickness of integument of two ecotypes. This study represents a baseline information for further studies, development of forecasting models and management of seed-borne diseases associated with common beans

Hormonal response and root architecture in Arabidopsis thaliana subjected to heavy metals

In this work, specific concentrations of cadmium, copper and zinc in double combination, were supplied for 12 days to growing seedlings of the model species Arabidopsis thaliana. Metal accumulation was measured in roots and shoots. Microscopic analyses revealed that root morphology was affected by metals, and that the root and shoot levels of indole-3-acetic acid, trans-zeatin riboside and dihydrozeatin riboside varied accordingly. Minor modifications in gibberellic acid levels occurred in the Zinc treatments, whereas abscisic acid level did not change after the exposition to metals. Reverse transcription polymerase chain reaction analysis of some genes involved in auxin and cytokinin synthesis (AtAAO, AtNIT and AtIPT) revealed that their expression were not affected by metal treatments. The root morphological alterations that resulted in an increased surface area, due to the formation of root hairs and lateral roots, could be signs of the response to metal stress in terms of a functionally-addressed reorientation of root growth. The root system plasticity observed could be important for better understanding the manner in which the root architecture is shaped by environmental and hormonal stimuli

Beneficial effects of Trichoderma harzianum T-22 in tomato seedlings infected by Cucumber mosaic virus (CMV)

The study of the biochemical and molecular mechanisms deriving from the host-pathogen-antagonist interaction is essential to understand the dynamics of infectious processes and can be useful for the development of new strategies to control phytopathogens, particularly viruses, against which chemical treatments have no effect. In this work, we demonstrate the ability of the rhizospheric fungus Trichoderma harzianum strain T-22 (T22) to induce defense responses in tomato (Solanum lycopersicum var. cerasiforme) against Cucumber mosaic virus (CMV, family Bromoviridae, genus Cucumovirus) strain Fny. A granule formulation containing T22 was used for treating the plants before, simultaneously or after the CMV inoculation, in order to study the molecular and biochemical aspects of the interaction between T22 and tomato against the virus. Reactive oxygen species (ROS) and the genes encoding for ROS scavenging enzymes were investigated. Histochemical analysis revealed a different increase in the superoxide anion (O2 ) and hydrogen peroxide (H2O2) content in plants infected by CMV alone or in the presence of T22, confirming the involvement of ROS in plant defense responses. Gene expression analysis suggested a definite improvement in oxidative stress when plants were treated with T22 after inoculation with CMV. In conclusion, our data indicate that Trichoderma harzianum T-22 stimulates the induction of tomato defense responses against CMV, an action that implies the involvement of ROS, pointing towards its use as a treatment rather than as a preventive measure

Trichoderma harzianum T-22 induces systemic esistance in tomato Infected by Cucumber mosaic virus

Understanding the induction of plant defenses against viruses using biocontrol agents is essential for developing new strategies against these pathogens, given the ineffectiveness of chemical treatments. The ability of Trichoderma harzianum, strain T-22 (T22) to control Cucumber mosaic virus (CMV) in Solanum lycopersicum var. cerasiforme plants and the changes in the physiology of tomato treated/infected with T22/CMV were examined. Plant growth-promoting effects, photosynthetic performance, reactive oxygen species scavenging enzymes, and phytohormones were investigated. T22 improved tomato growth in terms of plant height and improved photosynthesis, total chlorophyll content and plant gas exchange. In contrast, CMV induced a negative effect on dry matter accumulation and inhibited the photosynthetic capacity. The analysis of plant hormones demonstrated that treating with T22 before or simultaneously to CMV infection, led to a systemic resistance by jasmonic acid/ethylene and salicylic acid signaling pathways. Conversely, systemic resistance was abscissic acid-dependent when T22 treatment was administered after the CMV infection. In conclusion, the data reported here indicate that the T22-based strategy may be the most effective measure against CMV

Influence of Cultivation Areas on the Seed-Borne Pathogens on Two Local Common Bean Ecotypes of “Fagioli di Sarconi” PGI (Phaseolus vulgaris L.).

Abstract The “Fagioli di Sarconi” common beans, typical of Basilicata Region (Southern Italy), include different ecotypes protected by the European Union with the mark PGI (Protected Geographical Indication). The study aimed to determine the presence of seed-borne pathogens, isolated from two ecotypes of “Fagioli di Sarconi” common beans, “Ciuoto” and “Cannellino rosso”, in two different cultivation areas during the years 2018 and 2019, for identifying genotypes resistant and well adapted to climatic changes. The seeds were evaluated for seed-borne pathogens screening by using three validated seed health testing methods, according to the 2020 International Rules for seed testing. The washing test identified 18 fungal pathogens, different for ecotype and year of observation; the 1% sodium hypochlorite treatment strongly reduced the contaminants. With the blotter test, several saprophyte pathogens were found. Between paper test, specific for detecting the C. lindemuthianum, revealed the presence of this pathogen for both ecotypes and years, in all areas, and individuated some bacteria, too. In conclusion, this work highlighted differences by the two PGI common bean ecotypes in response to seed-borne pathogens resistance and environmental change due probably to their different thickness and polyphenolic content of integument

Fattori individuali e contestuali del burnout: una ricerca descrittiva sugli insegnanti curricolari e di sostegno

L’obiettivo principale di questo studio è valutare la relazione tra alcuni dei fattori individuali (assertività e strategie di coping) e contestuali (percezione del contesto lavorativo, attaccamento al lavoro, impegno organizzativo, coinvolgimento e soddisfazionelavorativa) che si legano alla comparsa della sindrome del burnout nell’insegnante. Lo studio ha coinvolto un gruppo di insegnanti curriculari (N=35) e un gruppo di insegnanti di sostegno (N=38), a cui sono stati somministrati dei questionari.I risultati confermano quanto emerge in letteratura nazionale e internazionale circa la presenza di evidenti elementi di complessità intrinseca legati alla categoria degli insegnanti di sostegno, più esposti degli altri a pratiche educative impegnative e a un maggior addensamento di emergenze educative, che sembrano predisporli a situazioni di maggiore rischio di esaurimento psico-fisico-sociale