Revolutionizing agriculture and health: Engineering tomatoes for high-yield saffron apocarotenoid production
image: Representative scheme of the carotenoid pathways in tomato and the crocins and picrocrocin pathways from saffron that were introduced into the tomato fruit.
Credit: Horticulture Research
Apocarotenoids, derived from the oxidative cleavage of carotenoids by carotenoid cleavage dioxygenases (CCDs), are crucial for biological functions in plants and animals, though their definition varies among scientific communities. In plant carotenoid biosynthesis, enzymes convert isoprenoids into carotenoids, leading to products like lycopene, lutein, and zeaxanthin, which play roles in photoprotection and detoxification. Zeaxanthin is a precursor for apocarotenoids like crocins in saffron, contributing to its color, taste, and aroma. While saffron cultivation is labor-intensive and costly, advancing metabolic engineering and synthetic biology offer promising solutions for cost-effective production. Current research focuses on extending the carotenoid pathway in alternative hosts like tomatoes, aiming to resolve traditional cultivation's high-cost and environmental challenges, and to explore the potential of these compounds in various industries.
In March 2022, Horticulture Research published a research entitled “Engineering high levels of saffron apocarotenoids in tomato ”.
In this study, researchers harnessed the natural carotenoid accumulation in tomato fruits to produce saffron's distinctive apocarotenoids, aiming to boost the nutraceutical properties of tomato-based products. They employed a combinatorial genetic approach by introducing the saffron genes CsCCD2L, CsUGT2, and UGT709G1 into tomatoes using fruit specific and constitutive promoters to optimize expression. Although not all transgenic lines were viable, those that produced fruits demonstrated higher antioxidant activities and distinct apocarotenoid profiles when compared to wild-type. Detailed analyses revealed that lines differed in the accumulation of crocins, picrocrocin, and other compounds, with certain lines outperforming others based on specific metabolite levels. While the overall carotenoid content in transgenic fruits was reduced, the enhanced accumulation of valuable apocarotenoids like crocins and picrocrocin was a significant trade-off. This transformation also affected the volatile compound profile, introducing novel apocarotenoid-derived volatiles and altering existing ones.
The study extended to evaluate the health benefits and industrial potential of these engineered tomatoes. The transgenic tomatoes not only showed an increased antioxidant capacity but also demonstrated a neuroprotective effect against Alzheimer's in C. elegans, highlighting their potential as a functional food. The researchers also explored the feasibility of using these tomatoes as a cost-effective alternative to traditional saffron production. They found that the engineered tomatoes could potentially offer a substantial reduction in production costs for saffron apocarotenoids, thereby addressing the economic and fraud issues associated with saffron cultivation.
In conclusion, this study successfully utilized tomatoes as a biotechnological platform to produce saffron apocarotenoids, leading to fruits with enhanced nutritional and therapeutic properties. The findings open avenues for using metabolic engineering in crops to produce valuable compounds affordably and sustainably, with broad implications for agriculture, industry, and health.
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References
Authors
Oussama Ahrazem1, Gianfranco Diretto2, José Luis Rambla3, Ángela Rubio-Moraga1, María Lobato-Gómez4, Sarah Frusciante2, Javier Argandoña1, Silvia Presa4, Antonio Granell4,* and Lourdes Gómez-Gómez1,*
Affiliations
1Instituto Botánico, Departamento de Ciencia y Tecnología Agroforestal y Genética, Universidad de Castilla-La Mancha, Campus Universitario s/n, Albacete 02071, Spain
2Italian National Agency for New Technologies, Energy, and Sustainable Development (ENEA), Biotechnology laboratory, Casaccia Research Centre, 00123 Rome, Italy
3Departamento de Ciencias Agrarias y del Medio Natural, Universitat Jaume I, 12006 Castellón de la Plana, Spain
4Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-Universidad Politécnica de València, Valencia 46022, Spain
About Antonio Granell
Antonio Granell is a research professor of the Spanish National Council (CSIC) working at the Instituto de Biología Molecular y Celular de Plantas de Valencia (Spain). Currently, he is a senior group leader at the Plant Genomics and Biotechnology department where he combines the development and characterization of natural genetic diversity panels and breeding populations with reverse genetics and biotechnology to understand the genetic basis of fruit quality traits and to develop tomato varieties and Solanaceae plants as factories for added value products. Special emphasis in the lab has been to use genomic tools to understand fruit ripening and postharvest not only in tomatoes but also in citrus and peaches.