Scutellarin from tomatoes? vacuum method powers synthetic biology in fruit
image: Scutellarin accumulation in vacuum-infiltrated tomato leaves.
Credit: Horticulture Research
Researchers have developed an improved vacuum-infiltration system that overcomes long-standing barriers in tomato genetic engineering. This innovative system enables high-efficiency Agrobacterium-mediated transient expression in both tomato leaves and, for the first time, attached fruits. The system facilitates rapid gene functional analysis and element screening, dramatically shortening experimental timelines. Key outcomes include successful expression of multiple reporter genes, identification of trichome-specific promoters, production of flavonoid-rich tomato lines, and synthesis of the high-value compound scutellarin. By enhancing the speed, reliability, and versatility of gene expression studies, this new method advances both fundamental research and synthetic biology applications in tomato.
Tomato (Solanum lycopersicum) is a globally important crop and a model system for plant molecular biology. However, the development of genetic tools has been hampered by the limitations of stable transformation—an approach that is labor-intensive, slow, and often ineffective in commercial cultivars. While transient expression methods have emerged as a promising alternative, syringe infiltration has limited success due to structural constraints of tomato tissues. Additionally, existing vacuum-infiltration systems are restricted to young or detached tissues, which are prone to decay. Based on these challenges, there is a critical need to develop a robust, high-efficiency transient transformation system suitable for whole plants, including attached fruits.
Scientists from Shanghai Jiao Tong University have published a study (DOI: 10.1093/hr/uhae197) on July 26, 2024, in Horticulture Research, reporting a significant improvement to the vacuum-infiltration method for tomatoes. The team developed a new device and protocol enabling successful Agrobacterium-mediated gene delivery to both tomato leaves and attached fruits. This method was validated using multiple reporter genes and applied to synthetic biology studies, including the production of flavonoids and medicinal compounds. The breakthrough addresses limitations of traditional genetic methods and opens new possibilities in tomato biotechnology.
The improved vacuum-infiltration system was engineered using a custom-built transformation device that ensures uniform Agrobacterium penetration without damaging tissues. The system demonstrated high expression efficiency for multiple fluorescent proteins (EGFP, YFP, CFP, mCherry) and the GUS reporter gene in tomato leaves. Importantly, it enabled the first successful gene expression in attached tomato fruits using the RUBY reporter, which visually confirms betalain pigment production. The study also identified a trichome-specific promoter, AaLTPpro, which effectively directed gene expression in tomato trichomes, highlighting its potential for metabolic engineering. Furthermore, a combination of transcription factors, AmRosea and AmDelila, significantly enhanced flavonoid content in both transiently transformed leaves and stable transgenic plants—though the latter exhibited growth inhibition.
A notable application was the transient biosynthesis of scutellarin, a flavonoid with cardiovascular benefits, through the introduction of three key genes from Erigeron breviscapus: EbFNSII, EbF6H, and EbF7GAT. Ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) confirmed successful production in tomato leaves. These results collectively establish the system as a rapid and reliable platform for gene function analysis and plant synthetic biology.
“This system is a game-changer,” said Prof. Kexuan Tang, the study's senior author. “It not only accelerates the experimental cycle in tomato research but also overcomes technical hurdles that have limited gene expression in fruits. The ability to produce functional compounds like scutellarin in tomato through transient expression paves the way for a new era of edible biofactories and rapid synthetic biology validation.”
The improved vacuum-infiltration system offers a versatile tool for genetic and metabolic studies in tomato, with direct implications for agriculture, nutrition, and pharmaceuticals. It allows rapid screening of gene elements, reducing reliance on stable transformation and expediting synthetic biology workflows. Its compatibility with both model and commercial tomato cultivars expands its utility across research and industry. Notably, the successful transient production of scutellarin demonstrates the system’s potential as a plant-based platform for producing high-value medicinal compounds. Future work may extend this strategy to other plant species, supporting scalable, sustainable, and cost-effective biosynthesis of nutraceuticals and therapeutics.
###
References
DOI
Original Source URL
https://doi.org/10.1093/hr/uhae197
Funding information
This work was supported, in whole or in part, by the National Key R&D Program of China (grant number: 2018YFA0900600), and the Bill & Melinda Gates Foundation (grant number: INV-027291).
About Horticulture Research
Horticulture Research is an open access journal of Nanjing Agricultural University and ranked number one in the Horticulture category of the Journal Citation Reports ™ from Clarivate, 2023. The journal is committed to publishing original research articles, reviews, perspectives, comments, correspondence articles and letters to the editor related to all major horticultural plants and disciplines, including biotechnology, breeding, cellular and molecular biology, evolution, genetics, inter-species interactions, physiology, and the origination and domestication of crops.