H2020 TOMACOP Project: Copper homeostasis and effects of copper deficiency on tomato plants and fruit quality
- Type Project
- Status Filled
- Execution 2019 -2021
- Assigned Budget 170.121,6 €
- Scope Europeo
- Main source of financing H2020
- Project website TOMACOP
We evaluated physiological and biochemical changes in the plant resulting from plant growth under suboptimal Cu availability through in vitro, hydroponic, and greenhouse assays. Root and shoot length were significantly reduced, as well as dry weight and biomass per plant. Flower number and total yield also decreased as a consequence of Cu-deficient conditions. In terms of external fruit quality and nutritional status, Cu-deficient availability did not alter color evolution during the fruit ripening process, but it accelerated the rate of fruit softening and increased internal acidity after harvest. In turn, this stress increased fruit antioxidant capacity, likely due to increased vitamin C content, but had little effect on total phenolic, flavonoid, and lycopene contents. Furthermore, the incidence of fruit cracking and susceptibility to pathogen infection increased in fruit harvested from plants grown under Cu-deficient conditions. Finally, the contents of micronutrients important for human health, such as Cu and Fe, were modified in response to Cu deficiency stress conditions.
These results have been divided into two different manuscripts and presented at international symposia and several dissemination seminars.
We also studied the molecular mechanisms underlying the Cu deficiency stress response in tomato plants and fruits. Six members of the copper transporter family (SlCOPT1-6) were identified, and their secondary and tertiary structures, potential interaction networks, and gene expression patterns were analyzed. Furthermore, we assessed their functionality using yeast complementation expression assays. These results indicate that SlCOPT1 and SlCOPT2 are fully functional and the most ubiquitously expressed COPTs in plant and fruit tissues. On the other hand, the expression of SlCOPT3 and SlCOPT5 is specialized in stem and fruit tissues. These results have been previously published (10.1016/j.ijbiomac.2021.10.032) and were presented at the 6th International ABS Conference through an invited paper. In parallel, we compared the transcriptome of different tissues (root, stem, leaf and fruit) of plants grown under Cu sufficiency and deficiency conditions.
The results of next-generation sequencing revealed a set of common responses aimed primarily at increasing Cu uptake in the root and enhancing its mobilization to the upper parts of the plant.
The main SlCOPT performing these functions was SlCOPT2, which indicates this Cu transporter as the most plausible target for the biotechnological improvement of Cu uptake and distribution in tomato plants using genome editing technologies. These results will be published in two independent manuscripts. Furthermore, comparative transcriptomic analysis of fruit harvested at the red-ripening (commercial) stage has revealed that this organ does not regulate a large number of biological processes in response to Cu deficiency stress. These data are very valuable, as they have allowed us to identify fruit specificities in the regulation of genes related to Cu homeostasis. This presents promising biotechnological potential to improve/optimize the micronutrient content of this product, which could have an impact on the human diet and, consequently, human health.
Copper (Cu) is a vital micronutrient that acts as a double-edged sword in living beings, as it is an active redox cofactor essential in biological processes, but it is toxic in excess. Suboptimal levels of Cu in the human diet can cause impaired neurological development and metabolic disorders. In plants, Cu plays an important role in key processes. Consequently, plants are also sensitive to the bioavailability of Cu in the soil.
Therefore, low Cu levels can affect pollen development and viability, as well as the regulation of iron deficiency responses, but its toxicity causes DNA damage, chlorosis, and inhibition of root growth, among other symptoms. Since nutritional deficiencies or excesses in plants are transferred to consumers, deciphering the regulatory mechanisms underlying Cu uptake and distribution in edible products is crucial to prevent deficient or toxic levels of Cu in horticultural crops that can ultimately affect human health. Furthermore, in Europe, around 20% of arable land is classified as Cu deficient, which has been compensated for through the use of Cu-enriched fertilizers. However, the EU warns that this practice entails high environmental costs and compromises food safety for consumers.
The objective of TOMACOP was to study the effects of deficient Cu availability in the soil on plant growth and development and on fruit nutritional status and quality using tomato (Solanum lycopersicum) as an experimental system. The main results indicate that deficient Cu availability had detrimental consequences on plant growth and yield and reduced the micronutrient value, marketability, and postharvest quality of the fruit.
The characterization of the components related to Cu homeostasis and the identification of tissue specificities in the molecular mechanisms regulating Cu uptake in this species have provided important clues for future biotechnological improvements aimed at solving the challenge facing EU agriculture.
Copper (Cu) is a vital micronutrient that acts as a double-edged sword in living beings, as it is an active redox cofactor essential in biological processes, but it is toxic in excess. In humans, Cu is acquired through diet, and its deficiency or excess causes significant diseases. Plants are also sensitive to the bioavailability of Cu in the soil, and their nutritional deficiencies or excesses are passed on to consumers.
Therefore, deciphering the regulatory mechanisms underlying Cu uptake and distribution in edible products is crucial to prevent deficient or toxic levels of Cu in horticultural crops that could ultimately affect human health. Furthermore, in Europe, around 20% of arable land is classified as Cu deficient, which has been compensated for through the use of Cu-enriched fertilizers. However, the EU warns that this practice entails high environmental costs and compromises food safety for consumers.
TOMACOP will study the effects of Cu deficiency on plant growth and development, as well as on nutritional status and fruit quality, using tomato (Solanum lycopersicum), one of the most important crops worldwide. The characterization of the components of Cu homeostasis and the identification of tissue specificities in the molecular mechanisms regulating Cu uptake will provide important clues for future biotechnological improvements aimed at addressing this challenge facing EU agriculture.
This proposal addresses a topic of global importance to agriculture and food science through cutting-edge technologies developed during this research. On the one hand, this project provides results that will contribute to optimizing tomato growing conditions and, therefore, reducing the loss of nutritional and external quality of the fruit and, consequently, the loss of economic value of fresh fruit.
Furthermore, the results obtained to date establish basic knowledge on tomato plants and fruits for the future development of biotechnological strategies aimed at improving resilience to Cu deficiency/toxicity. Furthermore, these results open new lines of research focused on disease resistance by improving Cu content in the fruit, which will lead to a reduction in pesticide use and a better understanding of the mechanisms of fruit cracking incidence, which will affect fruit marketing and food waste.
Both applied and basic research components are integral to the strategies the EU is currently promoting, as reflected in Horizon 2020, which designates food security, sustainable agriculture, and resource efficiency as key societal challenges.
Furthermore, the application of basic research to the improvement of crops tolerant to Cu stress represents a crucial challenge for food security in a global context where Cu is either a deficient nutrient in the soil or a toxic element accumulated as a result of irresponsible fertilizer use.
As the world's population continues to grow and life expectancy has also increased rapidly, it is not only important for human health to increase food production but also to improve its quality. The successful application of basic knowledge from plant science and genomics will be crucial for future food security and agroindustry worldwide. This translational research for the sustainable production of healthier, higher-quality food is a visible contribution of plant science not only to European society but also to global society.
- CONSEJO SUPERIOR DE INVESTIGACIONES CIENTIFICAS (CSIC)
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