The Peach RGF/GLV Signaling Peptide pCTG134 Is Involved in a Regulatory Circuit That Sustains Auxin and Ethylene Actions

In vascular plants the cell-to-cell interactions coordinating morphogenetic and physiological processes are mediated, among others, by the action of hormones, among which also short mobile peptides were recognized to have roles as signals. Such peptide hormones (PHs) are involved in defense responses, shoot and root growth, meristem homeostasis, organ abscission, nutrient signaling, hormone crosstalk and other developmental processes and act as both short and long distant ligands. In this work, the function of CTG134, a peach gene encoding a ROOT GROWTH FACTOR/GOLVEN-like PH expressed in mesocarp at the onset of ripening, was investigated for its role in mediating an auxin-ethylene crosstalk. In peach fruit, where an auxin-ethylene crosstalk mechanism is necessary to support climacteric ethylene synthesis, CTG134 expression peaked before that of ACS1 and was induced by auxin and 1-methylcyclopropene (1-MCP) treatments, whereas it was minimally affected by ethylene. In addition, the promoter of CTG134 fused with the GUS reporter highlighted activity in plant parts in which the auxin-ethylene interplay is known to occur. Arabidopsis and tobacco plants overexpressing CTG134 showed abnormal root hair growth, similar to wild-type plants treated with a synthetic form of the sulfated peptide. Moreover, in tobacco, lateral root emergence and capsule size were also affected. In Arabidopsis overexpressing lines, molecular surveys demonstrated an impaired hormonal crosstalk, resulting in a re-modulated expression of a set of genes involved in both ethylene and auxin synthesis, transport and perception. These data support the role of pCTG134 as a mediator in an auxin-ethylene regulatory circuit and open the possibility to exploit this class of ligands for the rational design of new and environmental friendly agrochemicals able to cope with a rapidly changing environment

Superossido dismutasi a rame e zinco di pagetopsis macropterus: caratterizzazione della sequenza codificante del cDNA

In questa tesi è presentata l’attività di ricerca che ha avuto come risultato l’amplificazione e il sequenziamento della regione codificante del cDNA di Pagetopsis macropterus. Tale sequenza è stata confrontata con quella di altri teleostei, sia antartici che non antartici, verificando il grado di conservazione di questo enzima, ricercando nuove conferme sull’andamento irregolare dell’evoluzione della superossido dismutasi a rame e zinco e proponendo un’analisi filogenetica che si inserisce in un più vasto studio riguardante la storia evolutiva dei teleostei che popolano l’Oceano Australe.ope

Sviluppo sondaggio post-occupativo WELL Building Standard per edifici residenziali

Il presente studio approfondisce e analizza il comfort e la qualit\ue0 globale degli ambienti interni negli edifici residenziali, basandosi sul protocollo di certificazione WELL Building Standard. Il WELL Building Standard pone al centro dell\u2019attenzione le condizioni di salute e benessere psicofisico di chi occupa un dato spazio costruito. I concetti alla base della certificazione WELL possono essere applicati a tutti i settori dell\u2019edilizia, e a tutte le destinazioni d\u2019uso degli edifici: terziario, istruzione, ospedaliero e al settore residenziale. Questo studio mira a: studiare i parametri e concetti alla base del protocollo WELL che definiscono la qualit\ue0 e il comfort negli ambienti interni; studiare i sondaggi esistenti Post Occupancy Evaluation (POE); e dopo un\u2019attenta analisi, sviluppare un sondaggio post-occupativo residenziale sulla base dei concetti del protocollo WELL Building Standard. Nella prima parte del lavoro sono stati approfonditi i dieci concetti del protocollo WELL come: Aria, Acqua, Alimentazione, Luce, Fitness, Comfort, Mente, Materiali, Comunit\ue0; i sondaggi esistenti (POE); i sondaggi esistenti pre-approvati da WELL; e infine le tematiche del comfort termico e di qualit\ue0 dell\u2019aria negli edifici residenziali. Nella seconda parte dello studio \ue8 stato sviluppato il progetto di ricerca definendo i metodi, le procedure e tempistiche, i tipi di analisi da condurre, individuando i partecipanti e casi studio, e delineando gli strumenti di misura utilizzati per condurre la ricerca. La parte finale di questa ricerca ha previsto una campagna di misurazioni fisiche all\u2019interno degli ambienti di studio, per analizzare e comparare i dati provenienti dai sondaggi in modo da verificare l\u2019influenza degli occupanti nella percezione dei parametri indoor. Nell\u2019ultima parte sono implementati e descritti i tipi di analisi e i risultati ottenuti

Application of Different Circadian Lighting Metrics in a Health Residence

During the last three decades, various scientific researchers analysed the connection between natural elements and human life, both as far as well-being and productivity. This study simulates circadian lighting metrics on elderly occupants in a healthcare residence, with different types of metrics. It presents an application of some metrics that try to quantify the effects of natural light on the human being. Circadian Action Factor, Circadian Stimulus, and Equivalent Melanopic Lux are considered. Starting from the spectral power distribution parameter, the three metrics are compared. The final aim is to build up a standard technique to represent the effect of key design choices on the accomplishment of endorsed circadian framework boost for healthcare residences occupied by elderly people

Ethylene-auxin crosstalk regulates postharvest fruit ripening process in apple

The ripening of climacteric fruits, such as apple, is represented by a series of genetically programmed events orchestrated by the action of several hormones. In this study, we investigated the existence of a hormonal crosstalk between ethylene and auxin during the post-harvest ripening of three internationally known apple cultivars: 'Golden Delicious', 'Granny Smith' and 'Fuji'. The normal climacteric ripening was impaired by the exogenous application of 1-methylcyclopropene (1-MCP) that affected the production of ethylene and the physiological behaviour of specific ethylene-related quality traits, such as fruit texture and the production of volatile organic compounds. The application of 1-MCP induced, moreover, a de-novo accumulation of auxin. The RNA-Seq wide-transcriptome analysis evidenced as the competition at the level of the ethylene receptors induced a cultivar-dependent transcriptional re-programming. The DEGs annotation carried out through the KEGG database identified as most genes were assigned to the plant hormone signaling transduction category, and specifically related to auxin and ethylene. The interplay between these two hormones was further assessed through a candidate gene analysis that highlighted a specific activation of GH3 and ILL genes, encoding key steps in the process of the auxin homeostasis mechanism. Our results showed that a compromised ethylene metabolism at the onset of the climacteric ripening in apple can stimulate, in a cultivar-dependent fashion, an initial de-novo synthesis and de-conjugation of auxin as a tentative to restore a normal ripening progression

Comparative transcriptome and metabolite survey reveal key pathways involved in the control of the chilling injury disorder superficial scald in two apple cultivars, ‘Granny Smith’ and ‘Ladina’

The low temperature normally applied to prevent fruit decay during the storage of apples, can also triggers the onset of a chilling injury disorder known as superficial scald. In this work, the etiology of this disorder and the mechanism of action of two preventing strategies, such as the application of 1-MCP (1-methylcyclopropene) and storage at low oxygen concentration in ‘Granny Smith’ and ‘Ladina’ apple cultivars were investigated. The metabolite assessment highlighted a reorganization of specific metabolites, in particular flavan-3-ols and unsaturated fatty acids, while the genome-wide transcriptomic analysis grouped the DEGs into four functional clusters. The KEGG pathway and GO enrichment analysis, together with the gene-metabolite interactome, showed that the treatment with 1-MCP prevented the development of superficial scald by actively promoting the production of unsaturated fatty acids, especially in ‘Granny Smith’. ‘Ladina’, more susceptible to superficial scald and less responsive to the preventing strategies, was instead characterized by a higher accumulation of very long chain fatty acids. Storage at low oxygen concentration stimulated a higher accumulation of ethanol and acetaldehyde together with the expression of genes involved in anaerobic respiration, such as malate, alcohol dehydrogenase and pyruvate decarboxylase in both cultivars. Low oxygen concentration, likewise 1-MCP, through a direct control on ethylene prevented the onset of superficial scald repressing the expression of PPO, a gene encoding for the polyphenol oxidase enzyme responsible of the oxidation of chlorogenic acid. Moreover, in ‘Granny Smith’ apple, the expression of three members of the VII subgroups of ERF genes, encoding for elements coordinating the acclimation process to hypoxia in plants was observed. The global RNA-Seq pattern also elucidated a specific transcriptomic signature between the two cultivars, disclosing the effect of the different genetic background in the control of this disorder

Functional characterization of a ripening induced RGF-like peptide hormone in peach

In the vascular plants the coordination of developmental processes, cell-cell interactions and physiological processes are mediated by the action of phytohormones, whose chemical structures include simple molecules as olefin (ethylene) and complex steroids as brassinolide. Moreover, little signal peptides were recognized to have a role as phytohormones. Such peptides were involved in defense response, callus growth, meristems homeostasis, root growth, organ abscission and hormone crosstalk. The peach peptide encoded by the ctg134 gene represents a possible candidate as mediator in the interplay between auxin and ethylene. Initially annotated as a gene of unknown function, it drawn attention because of its expression, noted by means of microarray experiments on ripening peach. Indeed, it is induced by ripening, but, unlikely many ripening-associated genes, it is also induced by auxin and 1-methylciclopropene (1-MCP) and repressed by ethylene. Recently it turned out that its sequence is similar to those of RGF (Root Growth Factors) genes, characterized in Arabidopsis thaliana only in 2010. The ctg134 promoter fusion with the GUS reporter gene was used to create transgenic lines in tobacco and Arabidopsis, that displayed a staining pattern associated to cells where an ethylene/auxin crosstalk might occur, such as lateral roots formation and organ abscission. Treatments with exogenous auxin on pctg134::GUS seedlings demonstrated that the promoter is able to respond to low concentrations of auxin and that the response reaches the maximum level within six hours from the begins of the treatment. The ctg134 overexpression in tobacco allowed to observe an increase of the root hair number and growth and the enlargement of capsules size. Both the phenotypes may be due to an enhanced sensitivity to ethylene. This aspect was confirmed by molecular analyses on ACO genes in tobacco seedlings overexpressing the peptide encoded by ctg134. The obtained data seem to confirm that ctg134 is really active in the crosstalk between the two hormones, being induced by auxin and leading to an increased ethylene sensitivity in some tissues. To facilitate the functional analysis of regulatory genes involved in fruit development and ripening, new tools for gene expression were set up by modification of a two-component expression system based on transactivation. This vectors were adapted for specific gene overexpression in tomato fruits and are now available to future functional characterizations of genes involved in ripening processes.Nelle piante superiori la coordinazione delle interazioni cellula-cellula, durante i diversi stadi di sviluppo, è mediata prevalentemente da ormoni vegetali la cui natura chimica spazia da semplici molecole, come l’etilene, a molecole dalla struttura più complessa, come i brassinosteroli. Inoltre sono stati recentemente riconosciuti come importanti segnali intercellulari anche piccoli peptidi, con funzione ormonale, in grado di coordinare e definire specifiche funzioni nelle piante. Questi sono coinvolti in numerosi processi, come le risposte di difesa, la crescita del callo, l’organizzazione del meristema, la crescita delle radici, i fenomeni di abscissione e il cross-talk tra ormoni. In pesco, il peptide codificato dal gene ctg134 rappresenta un possibile candidato come mediatore nell’interazione tra auxina ed etilene. Inizialmente annotato come gene a funzione sconosciuta, il ctg134 è stato identificato mediante esperimenti di microarray condotti nell’ambito di studi sul processo di maturazione della pesca. Ulteriori esperimenti hanno mostrato come tale gene sia indotto dalla maturazione e, diversamente dagli altri geni legati a tale sindrome, sia indotto dall’auxina e dall’1-MCP, ma represso dall’etilene. Recentemente è stato evidenziato come esso presenti numerose similitudini con i peptidi ormonali appartenenti alla classe RGF (Root Growth Factor), caratterizzati in Arabidopsis. Fusioni del promotore con il gene GUS sono state utilizzate per creare linee transgeniche di tabacco e Arabidopsis, nelle quali è stata evidenziata attività del promotore in cellule in cui ci potrebbe essere interazione tra auxina e etilene, come la formazione di radici laterali e l’abscissione di organi. Trattamenti con auxina esogena su germinelli di tabacco pctg134::GUS hanno permesso di evidenziare come la sequenza regolatrice risponda a bassi livelli di auxina esogena e la risposta sia massima entro 6 ore dall’applicazione dell’ormone. La sovraespressione del gene codificante il ctg134 in piante di tabacco ha reso possibile osservare nelle radici un aumento della lunghezza e del numero dei peli radicali e, nella parte riproduttiva, l’ingrossamento dell’ovario. Entrambi i fenotipi potrebbero essere dovuto a un’aumentata sensibilità all’etilene. Questo aspetto è stato confermato dall’analisi dell’espressione dei geni ACO in germinelli di tabacco che sovra-esprimono il peptide codificato dal ctg134. I dati ottenuti sembrano confermare come il ctg134 sia realmente attivo nel cross-talk tra auxina ed etilene, essendo indotto dall’auxina e portando ad un aumento nella sensibilità all’etilene in vari tessuti. Per facilitare l’analisi funzionale di geni regolatori implicati nel processo di sviluppo e maturazione del frutto, sono stati messi a punto nuovi strumenti per la sovra-espressione genica attraverso la modificazione di un sistema di vettori a due componenti basato sul fenomeno della transattivazione. Questi vettori sono stati adattati per ottenere un’espressione specifica nella bacca di pomodoro, e sono ora disponibili per futuri studi di caratterizzazione funzionale di geni coinvolti nel processo di maturazione