Studio delle variazioni delle comunità microbiche associate a coralli e delle difese immunitarie dell'ospite in risposta ad impatti climatici e antropici: un approccio combinato metagenomica - trascrittomica

Responsabili di progetto

Lucia Bongiorni, Seungshic Yum

Accordo

COREA DEL SUD - NRF - National Research Foundation of Korea

Bando

CNR/NRF 2014-2015

Dipartimento

Scienze del sistema terra e tecnologie per l'ambiente

Area tematica

Scienze del sistema Terra e tecnologie per l'ambiente

Stato del progetto

Nuovo

Proposta di ricerca

Coral reefs represent some of the most diverse ecosystems on Earth. These complexes biological structures deliver ecosystem goods, as for example for tourism and fisheries industries, and services (shoreline protection) providing vital sustenance to hundreds of millions of people in tropical and subtropical countries (Moberg & Folke, 1999, Ecol Econ 29:215-233). As counterpart, temperate and cold-water coral reefs are hotspot of biodiversity by providing protection from currents and predators, nurseries for Juvenile fish, feeding, breeding and spawning areas for numerous fish and shellfish species (Cerrano et al., 2010, Biodiv Conserv 19: 153-167; Bongiorni et al., 2010, Biol Cons 143: 1687-1700; Bo et al., 2012, PLoS ONE 7: e49870).
In the last decades corals have been threatened by overfishing, urban and agricultural runoff and water pollution. The loss of biodiversity is further exacerbated by climate change, ocean acidification and other anthropogenic impacts. Presently, corals are in serious decline. It is estimated that more than 30% of the world's reefs have been so damaged that recovery is no longer expected and close to 60% may be lost by 2030 (Wilkinson, 2004, Global Coral Reef Monit Net Austral Inst Mar Sci ). When degraded, coral reefs lose their original biological and ecological portraits and properties, in many instances, without any prospects of recovery. Environmental impacts are most likely responsible for the alteration or the physiological breakdown of the relationship between the coral host and its endosymbiotic microbial community, called as a whole "coral holobiont". Moreover it has been proposed that coral diseases considered one of the major cause of coral death, with rare exception, are opportunistic infections secondary to exposure to physiological stress (e.g. elevated temperature) that result in reduced host resistance (immune-defences) and unchecked growth of bacteria normally benign and non-pathogenic (Lesser et al., 2007, JEMBE 346 : 36-44).
In the framework of the increasing need for corals conservation strategies, it is important to identify and deal with emerging environmental stress and coral diseases. However many of the fundamental aspects of the coral holobiont-environment relationship remain poorly understood as well as the immune-defence capacity of corals to face environmental challenges. The constant environmental and microbial threats to which corals are subjected in their natural habitats provide means to investigate and understand the physiological principles that govern their defence mechanisms.
Both Italy and Korea are peninsulas surrounded by sea. Italy host a diversified community of temperate corals and several cold-water coral mounds have recently being discovered and mapped (Taviani et al. 2005, Deep coral growth in the Mediterranean Sea: an overview In: Cold-water Corals and Ecosystems, 137-156; Freiwald et al., 2009, Oceanogr.22: 58-74). Korea host high diversity of reef building stony corals (scleractinians, ICRI, 1996) and soft corals which contributes to the survival and maintenance of a rich community of marine animals and represent a renowned attraction for tourism.
This collaborative proposal focus on the discovery and characterization of corals-associated microbial communities and the occurrence of coral photogenic species in different environmental conditions using a metagenomic approach (454 amplicon- sequencing). Shifts in microbial communities' composition can provide insights into the microbial community-level changes that accompany coral stress and potentially facilitate coral disease outbreaks or additionally can help in identify opportunistic/pathogenic species associated with disease. At the same time we plan to detect and characterize expressed genes in corals participating in defence responses against infections and stress due to environmental changes using a transcriptomic approach (DD-PCR or microarray validated by qPCR). The application of the proposed technologies in assessing coral response to environmental change has the potential to advance the field of coral biology and provide valuable management tools for the rapid assessment of coral reef health. Both shift in diversity of the microbial consortia associated to corals and differential gene expression in corals are potential molecular biomarkers for the identification of environmental stressors. This approach may also provide some "keys" by selecting corals genotype, to restore marine populations undergoing grave constraints and biotope unbalances resulting from human activities.
In order to achieve our objectives we plan to focus on two selected species, one dominant in cold-water reefs and one soft coral species common in subtropical environments. In the framework of this proposal we plan to exchange coral materials and organize scientific meetings and collaborative laboratory work both in Italy and Korea. These will generally serve to integrate the state of the art and studies on coral ecosystems and conservation issues and in particular target emerging environmental problems and corals threats for both countries. Discussion will be dedicated to define better strategies to study the coral holobionts responses to differential disturbances and exchange the research techniques and data about the alteration of the microbial communities associated to corals in response to environmental changes, anthropogenic impacts and the relative corals response through the coral gene expression changes. In addition collaborative work will be carried out in both laboratories in order to acquire and exchange technical knowledge between partners.

Obiettivi della ricerca

The proposed joint CNR-NRF research activities are aimed at elucidating:
i) Shifts in coral microbial communities and the occurrence of coral photogenic species in different environmental conditions using a metagenomic approach (454 amplicon - sequencing);
ii) Pattern of genes differentially expressed in corals affected by environmental stressors or in presence of potential parasites/ pathogenic bacteria by using a transcriptomic approach
In order to achieve these objectives the Italian and Korean partners will focus mainly on two target coral species as cases study: a cold-water species and a tropical soft-coral species. Those species will be selected on the base of their dominance in the respective coral communities and their importance for the conservation of both countries' coral-ecosystems.

Ultimo aggiornamento: 07/11/2025