Periodic Reporting for period 1 - TOMACOP (Copper homeostasis and the effects of copper deficiency on tomato plants and fruit quality)
Reporting period: 2019-09-01 to 2021-08-31
TOMACOP aimed to study the effects of Cu deficient availability in the soil on plant growth and development and on fruit nutritional status and quality by using tomato (Solanum lycopersicum) as experimental system. Major results indicate that deficient Cu availability had detrimental consequences on plant growth and yield and reduced the micronutritional value, marketability and postharvest quality of the fruit. The characterization of Cu homeostasis-related components and the identification of tissue-specificities in the molecular mechanisms regulating Cu uptake in this species has provided important clues for future biotechnological improvements aimed to solve the challenge facing EU agriculture.
We also studied the molecular mechanisms underlying the Cu deficiency stress response in tomato plants and fruit. Six members of the copper transporters family were identified (SlCOPT1-6) and their secondary and tertiary structures, as well as the potential interaction network and gene expression patters were analyzed. Also, we assayed their functionality through complementation expression assays in yeast. These results point altogether that SlCOPT1 and SlCOPT2 are completely functional and the most ubiquitously expressed COPTs in the plant and fruit tissues. On the other hand, the expression of SlCOPT3 and SlCOPT5 is specialized in stem and fruit tissues. These results are already published (10.1016/j.ijbiomac.2021.10.032) and have been presented in the 6th ABS International Conference through an invited speech. In parallel, we have compared the transcriptome of different tissues (root, stem, leaf and fruit) of plants grown under Cu sufficiency and deficiency conditions. New generation sequencing results uncovered a set of common responses mainly directed to increase the Cu uptake in the root and to enhance its mobilization to upper parts of the plant.The major SlCOPT carrying out such functions was SlCOPT2, which point out this Cu transporter as the most plausible target for biotechnological improvement of Cu intake and distribution in tomato plants through genome-editing technologies. These results will be published in two independent manuscripts. On the other hand, the comparative transcriptomic analysis of the fruit harvested at the red ripe (commercial) ripening stage has revealed that this organ is not regulating a high number of biological processes in response to the Cu deficiency stress. These data are very valuable since they have allowed identifying fruit-specificities in the regulation of Cu homeostasis-related genes. This has a promising biotechnological potential in order to improve/optimize the micronutritional content of this product, which might has an impact on human diet and hence in human health.
Furthermore, translation of basic research into the breeding of Cu stress-tolerant crops is a very important challenge for food security under global conditions where Cu is either a nutrient lacking in the soil or a toxic element accumulated as consequence of irresponsible use of fertilizers. Because the global population continues to increase, and longevity has also been rapidly increasing, it is not only important for human health to increase food production but also to improve food quality. The successful application of basic knowledge from plant science and genomics will be crucial for future food security and agroindustry in the world. Such translational research for the sustainable production of more healthy and better foods is a visible contribution of plant science not only to European but also to worldwide society.