Drought remains one of the most significant threats to global agriculture, reducing yields and jeopardizing food security. In cucumbers, a water-intensive crop, drought stress directly limits productivity, while the number of lateral branches influences market preferences and yield potential. Previous studies identified abscisic acid (ABA) signaling as a key mediator of drought responses and developmental trade-offs, yet the genetic mechanisms coordinating branching and drought tolerance remained unclear. Understanding this regulation is vital for breeding resilient cucumbers that can adapt to varied environmental and market demands. Based on these challenges, in-depth research on the regulation of branching and drought tolerance is needed.
A research team from China Agricultural University has identified the CsTIE1–CsAGL16 regulatory module as a central mechanism coordinating cucumber branching and drought tolerance. The study, published (DOI: 10.1093/hr/uhae279) on October 2, 2024, in Horticulture Research, details how the interaction between CsTIE1 and CsAGL16 influences ABA catabolism, enabling plants to develop favorable shoot architecture while enhancing drought resilience. These discoveries provide new insights into cucumber biology and practical strategies for molecular breeding aimed at sustainable vegetable production.
The researchers first demonstrated that CsTIE1 directly interacts with the MADS-box transcription factor CsAGL16 at the protein level, validated through yeast two-hybrid, luciferase complementation, and co-immunoprecipitation assays. This interaction boosted the transcriptional activation of CsCYP707A4, a gene involved in ABA catabolism, thereby promoting lateral branch outgrowth. Loss-of-function Cstie1 mutants showed nearly 70% reduction in branch length and fewer branches overall, while CsAGL16 overexpression compensated for this defect, restoring branching vigor. Beyond development, drought assays revealed that Csagl16 mutants wilted severely with survival rates as low as 27%, whereas overexpression lines reached survival rates above 74%. Enhanced drought tolerance was linked to improved stomatal closure, expanded root systems, and elevated antioxidant enzyme activities, reducing oxidative damage. Similarly, Cstie1 mutants exhibited compromised drought resistance, but introducing CsAGL16 overexpression partially rescued this weakness. Together, these findings confirm that the CsTIE1–CsAGL16 module acts as a dual regulator, balancing vegetative growth with stress adaptation in cucumber.
“Understanding how crops simultaneously manage growth and stress tolerance is critical for future food security,” said Jianyu Zhao, senior author of the study. “Our discovery that CsTIE1 and CsAGL16 coordinate both branching patterns and drought responses highlights a genetic ‘switch’ that breeders can target. This dual-function module not only explains a long-standing biological question in cucumbers but also offers practical strategies to develop varieties tailored for regions facing water scarcity without compromising productivity.”
The identification of the CsTIE1–CsAGL16 module provides a valuable genetic resource for cucumber breeding programs. By fine-tuning this pathway, breeders can create drought-tolerant cultivars with shoot architectures suited to different markets—whether for high-branching varieties favored in processing or low-branching cultivars for fresh consumption. Beyond cucumbers, the study suggests that similar regulatory modules may exist in other crops, opening avenues for broader application in vegetable and fruit breeding. Integrating these insights into molecular breeding strategies will accelerate the development of climate-resilient horticultural varieties, reducing yield losses and ensuring sustainable food supply under increasingly variable environments.
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References
DOI
10.1093/hr/uhae279
Original Source URL
https://doi.org/10.1093/hr/uhae279
Funding information
This work was supported by grants from the National Natural Science Foundation of China (32025033 and 32372699), Pinduoduo-China Agricultural University Research Fund (PC2023B01002) and The Construction of Beijing Science and Technology Innovation and Service Capacity in Top Subjects (CEFF-PXM2019_014207_000032).
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.