Anthocyanins and terpenoids play central roles in fruit coloration, flavor, aroma, and nutritional value, yet manipulating their biosynthesis often leads to undesirable growth defects because these pathways are tightly linked to plant hormones. Cytokinins are known regulators of both plant development and secondary metabolism, but increasing cytokinin activity typically alters plant architecture and growth rates. Meanwhile, a lesser-studied group of cytokinin-related genes—tRNA-type isopentenyl transferases—are thought to serve basic, housekeeping functions rather than regulatory roles. Whether such genes could influence fruit metabolic quality without affecting growth remained unclear. Based on these challenges, it is necessary to conduct in-depth research on alternative genetic routes to enhance fruit quality while maintaining normal plant development.
Researchers from Nanjing Agricultural University and the University of Connecticut reported (DOI: 10.1093/hr/uhaf130) on May 26, 2025, in Horticulture Research that overexpressing the housekeeping gene FveIPT2 in woodland strawberry dramatically improves fruit quality. Using transgenic plants, the team showed that boosting this tRNA-type cytokinin-related gene significantly increased anthocyanin and terpenoid accumulation in ripe fruits, while leaving plant growth, fruit size, and sugar levels unchanged. The work challenges traditional views of housekeeping genes and highlights their untapped potential in crop quality improvement.
The researchers engineered strawberry plants to overexpress FveIPT2, a gene involved in tRNA modification and associated with cis-zeatin cytokinin production. Unlike classical cytokinin-related genes that strongly influence growth, FveIPT2 overexpression caused only minimal changes in overall cytokinin levels and produced no visible developmental abnormalities. Plants flowered and fruited normally, and fruit weight, shape, and sugar content remained unchanged.
Despite this physiological stability, the metabolic profile of the fruits changed markedly. Total anthocyanin, flavonoid, and phenolic contents increased significantly, resulting in deeper red coloration. Metabolomic analyses identified strong increases in nine specific anthocyanins, including cyanidin- and pelargonidin-derived compounds that contribute to pigmentation and antioxidant activity. At the same time, nearly half of all detected terpenoids were elevated, including monoterpenoids, sesquiterpenoids, and triterpenoids.
Notably, aromatic compounds linked to pleasant floral notes, such as linalool, increased, while compounds associated with harsher resinous odors decreased. Gene expression analyses confirmed the upregulation of key biosynthetic, regulatory, and transport genes involved in anthocyanin and terpenoid pathways. Together, these results demonstrate that FveIPT2 selectively enhances fruit metabolic quality without activating classical cytokinin signaling pathways or disturbing plant growth.
“This study shows that genes we usually think of as ‘housekeeping’ can have surprisingly specific and valuable effects,” the researchers noted. “By targeting a tRNA-type gene rather than classical hormone regulators, we were able to improve fruit color, aroma, and nutritional compounds without the growth penalties that often accompany metabolic engineering. These findings suggest that basic cellular pathways may quietly shape fruit quality, offering breeders new tools that are both effective and biologically gentle.”
The discovery positions FveIPT2 as a promising genetic target for fruit quality improvement in strawberries and potentially other horticultural crops. Because the approach enhances health-promoting pigments and aroma compounds without affecting yield or plant vigor, it may be particularly attractive for breeding programs focused on premium-quality fruits. More broadly, the work challenges the assumption that housekeeping genes play only passive roles in plant biology. By revealing their influence on secondary metabolism, the study opens new directions for crop improvement strategies that balance productivity, flavor, and nutrition—key goals for sustainable and consumer-oriented agriculture.
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References
DOI
10.1093/hr/uhaf130
Original Source URL
https://doi.org/10.1093/hr/uhaf130
Funding information
This work was financially supported by the National Natural Science Foundation of China (Grant No. 31672124).
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.