Plant steroid hormones speed up grape ripening and boost berry quality

By applying epibrassinolide (EBR), a synthetic BR analog, researchers accelerated berry coloration, boosted anthocyanin content, enhanced sugar accumulation, and promoted softening through cell wall modification. Transcriptomic analyses revealed that BRs not only regulate ripening directly but also interact with other hormone networks, including abscisic acid, ethylene, auxin, and cytokinin.

Grapes (Vitis spp.) are globally cultivated for their economic and nutritional value. Their ripening follows a tightly regulated process influenced by several plant hormones. Abscisic acid (ABA) and ethylene are well-known promoters, while auxin and cytokinin generally act as inhibitors. BRs, a class of more than 70 steroid-like molecules, have gained attention for their roles in plant growth, stress tolerance, and fruit development. In grapes, BRs levels naturally increase at the onset of ripening, while chemical inhibition delays véraison, underscoring their importance. Despite this, the gene networks through which BRs orchestrate ripening remain poorly understood. Due to these challenges, deeper research into BR-mediated transcriptional control of grape ripening is needed.

A study (DOI: 10.48130/fia-0025-0024) published in Food Innovation and Advances on 26 June 2025 by Xiangpeng Leng’s & Xudong Zhu’s team, Qingdao Agricultural University, demonstrates how fine-tuning BR pathways can improve grape flavor, appearance, and texture, offering a promising, eco-friendly strategy for viticulture and fruit quality enhancement.

The study employed a multi-tiered strategy combining physiological, biochemical, and molecular analyses to investigate how EBR, a brassinosteroid, regulates grape berry ripening. Exogenous application of EBR significantly accelerated development, with treated clusters achieving full coloration by day 15, accompanied by elevated endogenous BRs at days 5–10. Sugars including glucose and fructose accumulated more rapidly, while titratable acids such as tartaric, malic, and citric declined, enhancing flavor balance. LC–MS profiling revealed a marked increase in total anthocyanins, from ~85.5 to 179.4 mg/kg at day 10 and ~274.9 to 385.4 mg/kg at day 15, dominated by peonidin-3-O-glucoside (~50%) and supported by rising levels of malvidin-3-O-glucoside. Transcriptomic sequencing across four ripening stages generated over 100 Gb of data, identifying thousands of differentially expressed genes enriched in hormone signaling, phenylpropanoid/flavonoid biosynthesis, and carbon metabolism. BRs induced anthocyanin biosynthetic genes (VvPAL, VvCHS, VvF3H, VvUFGT), transport and methylation genes (VvGST, VvAOMT), and modulated sugar/acid metabolism genes while reshaping hormone networks by enhancing ABA and ethylene signaling and suppressing auxin-related transcripts. At the structural level, EBR reduced cellulose and protopectin, elevated water-soluble pectin, and up-regulated VvPME, VvEXP, and VvCEL, promoting berry softening. qRT-PCR validated RNA-seq patterns. Functional confirmation came from strawberry, where transient overexpression of VvDWF4, a key BR biosynthetic enzyme, increased BR content, doubled anthocyanin levels, intensified red coloration, and accelerated softening through cell-wall modification. Collectively, the results provide compelling evidence that BRs orchestrate grape ripening through coordinated regulation of secondary metabolism, hormone cross-talk, and cell-wall dynamics, offering a potential eco-friendly strategy to improve fruit quality.

The discovery positions brassinosteroids as powerful, eco-friendly tools for viticulture and fruit production. Low-dose applications of EBR could serve as a practical method to enhance grape berry quality—improving flavor, visual appeal, and market value while potentially reducing reliance on synthetic chemicals. By fine-tuning hormone cross-talk, growers could achieve more consistent ripening, shorten harvest windows, and improve storage properties. Beyond grapes, the results may apply to other fruit crops such as strawberries, tomatoes, and mangoes, where BRs influence ripening and softening. However, the relatively high cost of natural BRs may limit large-scale application, highlighting the need for affordable synthetic analogs or targeted gene-editing approaches to harness this pathway.

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References

DOI

10.48130/fia-0025-0024

Original Source URL

https://doi.org/10.48130/fia-0025-0024

Funding information

This work was supported by the Key Research and Development Plan of Shandong Province (Grant Nos 2022LZGCQY019, 2023TZXD015 and 2022TZXD0011), the National Natural Science Foundation of China (NSFC) (Grant Nos 32102353, 32202449, and 32202430), the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (Grant No. 24KJB210009), the Natural Science Research Project of Anhui Educational Committee (Grant No. 2024AH051983), the Natural Science Foundation of Jiangsu (Grant No. BK20190542), Shandong Provincial Natural Science Foundation (Grant Nos ZR2021QC005 and ZR2022QC018), Construction of genetic transformation of Grape (Grant No. SDAG2021A03), Inner Mongolia Science Technology Plan (Grant No. 2022YFDZ0029), the Unveiling and Commanding project of the West Coast new area of Qingdao (2022-23) and Qingdao Agricultural University Enterprise Cooperation Projects (Grant No. 660/2424191).

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Food is essential to life and relevant to human health. The rapidly increasing global population presents a major challenge to supply abundant, safe, and healthy food into the future. The open access journal Food Innovation and Advances (e-ISSN 2836-774X), published by Maximum Academic Press in association with China Agricultural University, Zhejiang University and Shenyang Agricultural University, publishes high-quality research results related to innovations and advances in food science and technology. The journal will strive to contribute to food sustainability in the present and future.