Periodic Reporting for period 2 - EVOfruland (Evolution of genetic network required for fruit and fruit-like structures development of land plants.)
Reporting period: 2023-09-01 to 2025-08-31
Fruits are novel organs that originated with the angiosperms. The fruit is not only complex, but also highly varied in structure and seed dispersal mechanisms across flowering plants (Fig.1). Seed dispersal is pivotal for plants species to survive, maintain a high level of biodiversity and colonize new habitats. Dry and fleshy fruits exploit different strategies to disperse seeds. Fruit diversity encompasses all ontogenetic changes undertaken by the gynoecium after ovule fertilization, already present in the last common ancestors of the flowering plants. Extant Gymnosperms (such as Ginkgo biloba) occupy a key phylogenetic position as sister to the angiosperms and are therefore key to understanding the origin and evolution of reproductive structures within angiosperms. Human and animal nutritional needs are mainly based on the intake of seeds and fruits which are also important sources of other priceless products useful for our well-being. Therefore, a great effort is required to increase plant food production in a world where the population is growing dramatically, and climate changes obviously pose new challenges for food sustainability. Any new insight about mechanisms underpinning fruit and seed formation is fundamental for transfer of the acquired knowledge from model systems to species used to feed the world.
Genomic and transcriptomic analyses during the development of the fruits and fruit-like structures put the basis for studying the conservation and divergence of the fruit gene regulatory network. Comparing molecular data shed more light on the origin and evolution of the fruit, and on the molecular difference between dry and fleshy fruits and fruit-like structures and provided an affordable tools to analyze the expression of genes and perform identification of the molecular/genetic mechanisms that contribute to the phenotypic diversity and adaptation and how they are linked with genome evolution and phylogeny. The spatio-temporal expression of key genes has been obtained for many species under study giving an overview about the time and the tissue of expression, clarifying the complex molecular network that underneath fruit development especially in non-model fruits for which very few studies are available, in spite of their importance as a potential food source compared to the few species we cultivate, also causing a sharp decrease in genetic variability. By comparing the functions of orthologous key regulators, the establishment of conserved and diverged pathways leading to fruit development in the various species with different fruit morphologies and characteristics (dry and fleshy fruit and fruit-like structures) were demonstrated. Moreover, EVOfruland shed light on the timing of the specific gene activity involved in a given species, to understand the spatial and temporal correlation between different genes involved in the development of reproductive structures in the same species. Plant evolution has been shaped by key morphological and developmental novelties that have improved plant's fitness as terrestrial organisms. Describing and discussing the evolution and development of some of these traits, emphasizing those that have allowed seed plants, and especially flowering plants, to diversify and become dominant on Earth, it was possible to hypothesize on the evolutionary paths taken using comparisons between non-model systems versus model systems, in which clearer pathways are described during gynoecium and fruit/fruit-like development. Flower and fruit development requires the precise spatio-temporal coordination and the cooperative action of hormones and genes. Database generated by the partners allowed the description of the overall expression pattern to understand the role of the different hormones involved in this process. An immunolabeling protocol was setup to detect hormones in Arabidopsis fruits and then applied to detect hormones in different species as Ginkgo, tomato. The effect of exogenous hormone applications on different species are crucial as hormonal treatments could be applied to fruit production as the development, the ripening, the maintenance of organoleptic qualities and shelf life of fruits in the market depends on hormonal control. The project provided advancement of knowledge on auxin-cytokinin interaction and its participation during different stages of the gynoecium development, on the role of auxin in Gymnosperm reproductive structure development, on the role of gibberellin in fruit maturation in Arabidopsis and proposed a model of tomato ripening regulation by TFs and ethylene. The hormonal control has deep effects on the cell walls that are dynamic structures whose composition evolves constantly during fruit development. Some work has been carried out to describe how enzymes involved in the biosynthesis, modification and degradation of cell wall components are related to the formation of gynoecium, ovule, seed and fruit development. Comprehensive CW models in the redesign of plant CWs were proposed for agronomically viable production, aiming to improve fundamental commercial traits such as seed and fruit yield, and fruit ripening processes. The integration of molecular, biochemical, developmental, and biophysical studies on a larger scale is fundamental to determine the full potential of CW-modifying agents for the modulation of differentiation processes.In total 40 papers, acknowledging the EVOfruland RISE projects, have been published open access in renown scientific journal in the plant science-plant reproduction fields: 29 research articles, 6 review papers, 3 book chapters, 1 perspective, 1 Editorial). All publications are deposited in platforms connected with Open repositories for EU-funded research outputs from Horizon Europe accordingly to Grant Agreement article 29.2.
The results obtained figure out which components are involved and how they could be interconnected about the evolution of the mechanisms involved in fruit/fruit-like development, providing potential powerful tools to increase the fruit production from a qualitative and quantitative point of view (introduction of neglected or under considered fruit species in the market, targeted crossings to obtain more adaptable varieties with a higher yield). Thus, the impact of the project is relevant taking in account that the scientific achievements obtained pave the way for applied innovative strategies to better face with the challenging environmental conditions in which fruits and seeds for humankind will have to be produced.
In addition results have demonstrated a great potential impact on the society and on younger people (schools and families) partecipating to practical and training activities, conferences and workshops on fruit biodiversity and development, organized at the Botanical Gardens (Fig.2 and 3). These kind of activities collected interests stimulating many questions about fruits that often were not generally known (i.e. exotic fruits, dry fruits) and made aware the general public about the importance to safeguard biodiversity of plants and of the products we get from them that none of us can do without now.
A very strong cohesion has been established among the involved research partners; we are highly motivated in continuing research and in strengthening the partnership in the field of evolution of GRN controlling fruit development.
In addition results have demonstrated a great potential impact on the society and on younger people (schools and families) partecipating to practical and training activities, conferences and workshops on fruit biodiversity and development, organized at the Botanical Gardens (Fig.2 and 3). These kind of activities collected interests stimulating many questions about fruits that often were not generally known (i.e. exotic fruits, dry fruits) and made aware the general public about the importance to safeguard biodiversity of plants and of the products we get from them that none of us can do without now.
A very strong cohesion has been established among the involved research partners; we are highly motivated in continuing research and in strengthening the partnership in the field of evolution of GRN controlling fruit development.