In plant meristems, stem cells continuously originate daughter cells that eventually differentiate into diverse tissues and organs. As plants are sessile organisms, meristem activity and thus organ development are strongly influenced by environmental conditions.
Understanding how meristems control organ growth adapting it to the environment is a major question in developmental biology.
This project will address this question in Arabidopsis focusing on salt stress as an environmental challenge. As the root is the plant organ that first perceives salt stress, the project specifically concentrates on genetic traits and mechanisms that that adapt the activity of the root meristems to this environmental stress. In particular, the project aims to assess whether the ARR1/GH3.17/PIN5 molecular module, previously identified as crucial in controlling Arabidopsis root meristem development, also mediates meristem response to salt stress in Arabidopsis. As miRNA are important signals in controlling root growth, the project also aims at establishing whether miRNAs, controlling root grow in response to salt stress, exist.
Salt stress is among the major abiotic stresses, severely limiting the yield of crops. It is thus imperative that countries like Italy, where crop production is an important economical resource, develop innovative and efficient approaches to effectively tackle with this issue. This project has therefore a strong scientific content as well as a relevant agronomic significance. The proponents will take advantage of state of the art techniques including the development of a root grow computational modelling.
Continuous organ production, characteristic of plant growth, depends on the activity of stem cells lying within meristems and capable of continuous self-propagation. Developmental events producing different tissues and organs need to be coordinated in a correct spatio-temporal manner, and must also be capable of adequately respond to changing environmental conditions as plants are sessile organisms. Therefore, meristems must be characterized by strong flexibility and fast re-programming to adapt organ growth to the environment: how this is achieved remains a major question in developmental biology.
Our project will address this question by utilizing the root of Arabidopsis as a model system, and salt stress as an environmental challenge.
Roots are particularly tractable in the context of integrating developmental patterning and stress responses, as they are the first organ to sense environmental changes leading to stress, including increases in salinity or toxic soil elements, reduction in available water or shortage of oxygen in hypoxic soils. The response to these stimuli is first set in place by roots, and only later the transmission of signals to the shoot leads to a global plant response. Thus, the capability of the root meristem to sense specific stresses is crucial to plant health. Studying roots has always been limited by the difficulty of accessing and manipulating them. The partecipants already possess all the necessary technical skills and expertise to manipulate this organ.
Our proposal integrates several complementary expertise, resulting in a strong scientific added value. The multidisciplinary nature of the work described will be crucial in tackling the biological problems faced, and will be of significant educational value as it will expose and train young researchers to multiple scientific approaches. We will invest in human capital, and the impact of our proposal will also be measured by the future career development of young scientists employed in this project.
Although this proposal is focused on cutting-edge scientific topics and approaches, and it does not include explicit applied goals, it nevertheless opens the way to important agronomical and biotechnological applications. Indeed, root architecture critically influences water and nutrient uptake efficiency, and consequently the overall performance of (crop) plants. Despite this evidence, plant breeders have not selected genetic traits specifically controlling root development, and they have instead focused almost exclusively on aerial traits since the Green Revolution in the 1960s. The need to improve the ability to adapt to a changing environment in crops by manipulating root architecture is, however, becoming increasingly urgent. The potential impact on world agriculture is such that Jonathan Lynch (2007) has called for a ¿Second Green Revolution¿, which would focus on root development and should be made ¿a priority for plant biology in the 21st century¿. In the next decades, the EU food system will have to change considerably to pursue the objectives set by the European Green Deal in trying to reach a climate neutral footprint by 2050: this goal will have to be achieved through science-based solutions. In this perspective, gaining knowledge and control of the mechanisms that govern the response of root growth to high salt stress would provide important traits and powerful breeding tools to improve plant performances. This is particularly true in the Mediterranean basin, where the effects of climate change and the impact of salinity stress will be stronger than elsewhere. Even more so in Italy, where agricultural practise, are often in areas subject to soil salinization, and where technological innovations in agriculture need to be urgently implemented to keep the pace with other countries.