Sucrose is essential for plant growth and development, serving as both an energy carrier and a regulator of cellular processes. In fruits like tomatoes, sugar metabolism critically shapes flavor, texture, and postharvest quality. However, the detailed mechanisms linking sucrose breakdown to fruit ripening and stress responses have remained elusive. Previous studies highlighted the importance of sugar transporters and enzymes like sucrose synthase and cell wall invertase but left gaps in understanding the role of vacuolar invertases during ripening. Due to these challenges, a deeper exploration of vacuolar invertase function in tomatoes is necessary to improve fruit quality and shelf stability.
A research team from Sichuan University and collaborating institutions published a study (DOI: 10.1093/hr/uhae283) on October 2, 2024, in Horticulture Research, detailing the role of the vacuolar invertase gene SlVI in regulating tomato fruit quality. Using CRISPR/Cas9 gene editing and overexpression techniques, the researchers demonstrated that manipulating SlVI alters sugar accumulation, strengthens fruit firmness, and boosts resistance to fungal pathogens. Their work provides new genetic targets for breeding better-tasting, longer-lasting tomato varieties, offering promising strategies to reduce postharvest losses.
The team found that SlVI is specifically activated during tomato fruit ripening. Overexpressing SlVI led to larger leaves and earlier flowering, but did not significantly improve fruit quality. In contrast, SlVI knockout lines exhibited remarkable postharvest benefits: sucrose content increased approximately 16-fold compared to wild-type fruit, while glucose and fructose levels dropped, reflecting inhibited sucrose hydrolysis. Knockout fruits also showed improved firmness, attributed to denser cell structures and elevated levels of cellulose, hemicellulose, and protopectin in the cell wall. Additionally, the knockout fruits accumulated more naringenin, a beneficial flavonoid linked to enhanced stress resistance. Transcriptome analyses revealed downregulation of starch degradation genes and upregulation of genes involved in flavonoid biosynthesis, cell wall strengthening, and cuticle formation. These molecular shifts explain the observed improvements in shelf life and resistance to Botrytis cinerea infection. Overall, the study illustrates how precise modulation of sugar metabolism can transform both the eating quality and storability of tomato fruits.
“Our findings highlight the pivotal role of sugar metabolism not only in shaping fruit taste but also in controlling structural integrity and disease resistance after harvest,” said Dr. Mingchun Liu, lead author of the study. “By targeting SlVI, we demonstrate a powerful strategy to simultaneously enhance flavor, texture, and shelf life, offering valuable tools for breeding next-generation fruit crops that meet both consumer expectations and supply chain demands.”
The discovery of SlVI's role in tomato postharvest physiology opens new avenues for crop improvement. By editing this gene, breeders can develop tomato varieties with naturally higher sucrose content, firmer textures, and greater fungal resistance—traits highly desirable for commercial production and global food security. Moreover, the principles uncovered here could extend to other fruit crops, inspiring broader applications in agricultural biotechnology. Future research will focus on fine-tuning SlVI regulation to optimize the balance between fruit sweetness, texture, and resilience under various storage and transportation conditions.
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References
DOI
10.1093/hr/uhae283
Original Source URL
https://doi.org/10.1093/hr/uhae283
Funding information
This work was supported in part by the National Natural Science Foundation of China (No.32102409, No.32172643, No.32172271), the Science and Technology Planning Project of Guangxi (GuikeAA22068088-1), the Institutional Research Funding of Sichuan University (2022SCUNL105), the Applied Basic Research Category of Science and Technology Program of Sichuan Province (2021YFQ0071; 2022YFSY0059-1; 2021YFYZ0010-5-LH), and the Technology Innovation and Application Development Program of Chongqing (cstc2021jscx-cylhX0001).
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.