For the first time, researchers have detailed a complete molecular circuit where two major plant hormones—ethylene and abscisic acid (ABA)—actively promote each other's production to drive the rapid softening of persimmon fruit. This study uncovers the specific transcription factors and genes that form this self-amplifying loop. The discovery provides a new framework for understanding fruit ripening and offers precise targets for interventions aimed at extending shelf life and reducing postharvest losses.
While it is known that ethylene and abscisic acid (ABA) both play key roles in fruit ripening, how these two hormones interact to regulate the delicate process of softening, particularly in persimmon, has remained a mystery. Previous research has shown they can influence each other, but the exact molecular "switchboard" controlling this crosstalk was unclear. Based on these challenges, there is a clear and pressing need for an in-depth investigation into the specific molecular mechanisms that govern this hormonal interplay during persimmon fruit softening.
A collaborative team of researchers from Northwest A&F University, Northwest University, Baoshan University, and Anhui Agricultural University in China has now solved this puzzle. Their findings, published (DOI: 10.1093/hr/uhag055) in the June 2026 issue of Horticulture Research , reveal a synergistic feedback loop where ethylene triggers ABA production, which in turn ramps up ethylene synthesis, creating a cascade that accelerates the softening process. The research identifies two NAC transcription factors as the master regulators of this dual hormonal pathway.
The team began by confirming that exogenous ethylene and ABA treatments each promoted softening in persimmon fruit. However, the key finding was that they also stimulated the biosynthesis of the other hormone. Ethylene treatment boosted endogenous ABA content, while ABA application advanced the fruit's natural ethylene peak. To find the link, they analyzed the fruit's transcriptome and identified ethylene-induced transcription factors. One, DkNAC26, was found to bind directly to the promoter of the ABA biosynthesis gene DkNCED2+3 ', activating its expression and increasing ABA production. On the flip side, ABA was found to induce a separate transcription factor, DkNAC28. This protein then bound to the promoter of the ethylene biosynthesis gene DkACS1 , activating it and leading to a surge in ethylene production. The authors confirmed these interactions through a suite of molecular assays, including dual-luciferase reporter assays, yeast one-hybrid assays, and electrophoretic mobility shift assays (EMSA). Finally, they validated the system's function by transiently overexpressing these transcription factors in persimmon fruit discs, which led to the predicted increases in ABA and ethylene.
"This is the first time we've been able to draw a complete molecular map showing how ethylene and ABA 'talk' to each other to soften fruit," the authors said. "We found that DkNAC26 acts as a bridge for ethylene to turn on ABA production, while DkNAC28 does the opposite, allowing ABA to boost ethylene. It's a powerful, self-reinforcing loop that quickly drives the fruit to soften." They added that this discovery is like identifying two key gears in a machine; by understanding these gears, we can now think about how to slow them down.
The implications of this discovery are significant for the agricultural industry. By identifying DkNAC26 and DkNAC28 as central regulators of this hormonal feedback loop, the study provides new genetic targets for breeding programs. Selecting persimmon varieties with naturally lower activity of these genes could lead to fruit that softens more slowly, extending their shelf life and reducing spoilage during transport and storage. Furthermore, this knowledge paves the way for developing new, more targeted postharvest treatments, such as specific inhibitors for these transcription factors, that could be applied to control the softening process, ultimately reducing food waste and improving fruit quality for consumers worldwide.
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References
DOI
Original Source URL
https://doi.org/10.1093/hr/uhag055
Funding information
This work was supported by the National Natural Science Foundation of China (32272780), the Yunnan Provincial Young and Middle-aged Academic and Technical Leader Reserve Talent Program (No. 202405 AC350101), the Chinese Universities Scientific Fund (2452022344), and the start-up funds of Northwest A&F University awarded to Q.Z. (Z1090222008) and Y.X. (Z1090124082).
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.
Horticulture Research
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ABA–ethylene crosstalk accelerates persimmon fruit softening via induction of DkNAC26 and DkNAC28
28-Feb-2026
The authors declare that they have no competing interests.