Danilo Santoro
Ciclo: XXXIV
Data inizio: 31/10/2018
Curriculum: Agroalimentari
Borsa: UniCT
Titolo tesi: Transcriptional dynamics of Arundo donax L. ecotypes to long-term salt and cadmium treatments by unigene-based RNA-Seq
Abstract: Global energy demand has been under intense pressure over the last few years, thus many research efforts have been made in many countries in order to evaluate and pose sustainable strategies. Sustainable biomass production by bioenergy crop on non-arable lands can play a crucial role not only in reducing global Greenhouse gas (GHGs) emission responsible for climate change but also providing a significant contribution to satisfy the increasing demand of sustainable energy production without any further risks on food security. The second generation of biofuels, which comes from living organisms, called bioenergy crops, have been considered better biomass producers than food crops, in fact they reach higher ethanol yields per unit of cultivated area. Among them, Arundo donax L. is the most promising species for bioenergy production in the Mediterranean basin due to its high yield, low input requirements and its capability to grow on marginal land and in adverse environmental conditions. Although the capability of A. donax to withstand a wide range of abiotic stresses condition has been reported worldwide, the investigation at molecular level is just at the beginning. Considering the impact of soil salinization on agricultural areas situated in the Mediterranean basin as well as the lack of information about the molecular mechanism involved in A. donax response to salt stress, we de novo sequenced, assembled and analysed the leaf transcriptome of two A. donax clones (G2 and G34) subjected to two levels of long-term salt stress treatment (namely, S3 severe and S4 extreme). The picture that emerges from the identified genes related to salt stress response in G2 is consistent with a dose-dependent response to salt, it also suggests a deep re-programming of the transcriptomic machinery in the case of S4 extreme salt stress condition, whereby a dramatic switch from C3 to C4 Calvin cycle likely occurred. Although A. donax propagates itself vegetatively by rhizomes and stem cutting nodes, variation in gene expression between G2 and G34 ecotypes occurred not only in salt treated but also in untreated samples. Indeed, the severe salt treatment in G34 ecotype resulted in a lower number of DEGs when compared to the same condition in G2 ecotype, indicating a lower re-adjusting of the gene expression. Nevertheless, the comparative analysis between S4 (extreme salt stress) G2 with S3 (severe salt stress) G34 conditions outlines a similar response and suggests that G34 ecotype tries to deal with stress condition as soon as S3 salt dose is applied. Moreover, given the ongoing increase of contaminated soils as well as the remarkable resistance of A. donax to heavy metals, we carried out a global de novo transcriptomic analysis in leaves and roots of G10 A. donax ecotype subjected to cadmium stress condition. By analysing the differential gene expression data, clear organ-specific differences emerged leading to the identification of specifically up-regulated genes in the Cd-treated roots compared to Cd-treated leaves. It is worthwhile to note that the obtained transcriptomic data indicate that after Cd uptake by plant roots, it is likely that only a small portion reaches the upper arial plant parts, since a low number of DEGs were retrieved in leaf tissue under cadmium treatment indicating a major role of roots in Cd detoxification. Based on transcriptomic data, the long-term exposure to Cd induced the expression of signaling molecules devoted to induce a downstream signal cascade activated by the phytohormone ethylene. In addition, the results showed a strong regulation of oxidative-responsive genes followed by the induction of transcripts involved in cell wall remodelling and lignification in Cd-treated roots. The identification of candidate genes involved in salt- and cadmium stress response constitute an important database resource towards the characterization of the molecular basis for the high resistance of A. donax to unfavourable environmental conditions. Many of the unigenes identified have the potential to be used for improving several important traits and for developing A. donax varieties with enhanced productivity and tolerance to different environmental scenarios. In addition, the identified SSRs addressed many challenges to discover molecular markers suitable for marked-assisted selection (MAS) in the breeding programs, to elucidate the interspecific phenotypic variation within A. donax ecotypes. Globally, these results support the cultivation of A. donax ecotypes in contaminated soils in order to only to avoid the competition with food crops but mainly to fulfil the sustainable energy demand.
Tutor: Lo Piero
Data Conseguimento Titolo: 08/04/2022
Linkedin: Indicate il link
Email: danilosantoro92@hotmail.it
Periodi all'estero- Sede e data: Universitat Politecnica de Valencia, Instituto de Biologia Molecular y Celular de Plantas (IBMCP). Tutor: Dott. Diego Vicente Orzáez Calatayud. Data: 01/06/2021 - 19/12/2021
Esperienze post-Dottorato ed attuale occupazione: Post Doc Fellow (da 02/2022 fino a 12/2022) presso Alzheimer's Center Institute at Temple University (Philadelphia, PA, USA). Borsa di ricerca di 12 mesi presso Di3A. Vincitore di un assegno di ricerca biennale presso l’Università di Perugia (2023-2025)