Physiological performance of truffle-colonized host OAK trees and the impact of water and nutrient limitations
The TUBERLINKS project is a highly innovative proposal gathering basic and applied research to optimise management practices for black truffle production. The overall aim of TUBERLINKS is to provide new knowledge on the ecological interactions of truffle forests and plantations, both above- and belowground, and their links with the host-tree physiology, to design optimised, knowledge-based strategies for sustainable management of truffle orchards.
The overarching hypothesis is that understanding the truffle life cycle and the ecology (biodiversity, functioning) of the whole soil-truffle-host system, and of its interactions with the environment (climate, soil, water/nutrient availability), will enable the optimal management of black truffle agro-forestry systems. Three main general hypotheses are proposed:
H1) The development of truffle mycelium generates an area with scarce vegetation around the host tree environment, the "brûlé" or burnt area. We hypothesize that this “truffle environment” mimics a disturbed soil ecosystem where different above- and belowground successional processes can be revealed, affecting the overall ecosystem structure and function.
H2) Truffle requirements for host carbohydrates will determine the trade-offs with the tree-host and companion plants. We hypothesize that the ecophysiological status of the host plant, e.g. Mediterranean oaks, is a major driver of belowground microbial interactions and function, affecting truffle production.
H3) The cultural techniques applied in truffle plantations are mainly based on empirical practices from other crops and can be refined considering the complexity of the plant-fungal-soil interactions. We hypothesize that it is possible to increase truffle yields by optimising cultural practices in truffle orchards through a better understanding of the whole truffle-host-soil system.
To address these hypotheses, the TUBERLINKS project consists of three General Objectives, tightly interlinked:
Objective 1: To study the impact of truffle mycelium on the soil environment (physic-chemistry, biodiversity), its temporal dynamics in wild and managed truffle systems, and to evaluate the functional consequences (carbon flux, nutrient cycling).
Objective 2: To evaluate the physiological performance of truffle-colonised oak trees and the impact of water scarcity (soil- and atmospheric-driven) and nutrient limitation on the host tree-soil-system.
Objective 3: To refine the truffle cultural techniques based on the physiological needs of the host tree and the abiotic/biotic soil dynamics, considering the whole tree-truffle-soil system.
To address these objectives, a variety of tools will be used, from classical ones such as sampling of soil, truffles and other organisms, to molecular and isotopic techniques and cutting-edge remote sensing technologies, both in field trials and in mesocosms designs.
TUBERLINKS will generate new knowledge for a wide range of end-users and stakeholders on: (i) the truffle ecology and biodiversity interactions in wild and managed truffle-producing systems, (ii) the functioning of the soil truffle-environment, considering key biological players and indicators, (iii) the host-tree ecophysiological cues linked to the truffle production, (iv) the susceptibility of truffle agroforestry systems to management and environmental limitations, and (v) the sustainable truffle management taking into account the trade-offs and synergies of the soil-truffle-host complex.