BpERF1A partnership strengthens drought resilience in birch

 Drought can quickly turn a promising forest seedling into a damaged plant by disrupting water balance and triggering oxidative stress. A new study identifies a molecular control system that helps white birch withstand these pressures. The drought-responsive transcription factor BpERF1A activates protective genes, strengthens antioxidant defenses, raises proline accumulation, and limits damage caused by reactive oxygen species (ROS). It also works with another transcription factor, BpRAV1, to intensify expression of the dehydrin gene BpDHN. Together, these coordinated responses reduced water loss, preserved chlorophyll and fresh weight, and improved recovery after prolonged water deprivation, revealing a potential genetic route toward more drought-resilient forest trees and climate-ready breeding in woody plants. 

As climate change expands drought-prone and degraded landscapes, forestry faces a difficult dual task: restoring ecosystems while maintaining supplies of high-quality timber. Trees cannot escape water shortage, so they depend on layered defenses that regulate water use, stabilize cellular structures, adjust hormone signals, and remove harmful oxidants. Ethylene-responsive factor (ERF) transcription factors (TFs) are known to coordinate stress responses, yet their partners and downstream targets remain less clearly defined in woody species than in annual crops. White birch, Betula platyphylla, is fast-growing and economically useful, but increasingly vulnerable to water scarcity across its planting range. Given these challenges, deeper investigation is needed into the transcriptional networks that enable birch to survive drought.

Researchers at the State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, reported (DOI: 10.1093/hr/uhag133) the findings on April 7, 2026, in Horticulture Research. The team combined drought-response transcriptomics, stable and transient genetic transformation, physiological measurements, promoter-binding assays, and protein-interaction analyses to map how BpERF1A controls drought acclimation in white birch. Their results place BpERF1A at the center of a regulatory module that activates dehydrin and jasmonate-related defenses while cooperating with BpRAV1 to strengthen reactive oxygen species removal, membrane stability, and cellular protection during sustained water shortage.

The researchers first found that the gene BpERF1A was strongly induced by polyethylene glycol 6000 (PEG6000)-simulated drought, with expression peaking after 12 hours in roots and leaves. They then produced birch lines that overexpressed or suppressed BpERF1A. After 15 days without watering, overexpression lines retained more chlorophyll and fresh weight, lost water more slowly, and showed less membrane injury than wild-type (WT) plants, whereas suppression lines were more sensitive. These plants also accumulated less hydrogen peroxide and superoxide while displaying higher superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities, together with increased proline, an important osmoprotective compound.

Mechanistic tests showed that the BpERF1A protein directly bound G-box elements in the promoters of BpDHN, encoding a dehydrin, and BpAOS, encoding allene oxide synthase. Chromatin immunoprecipitation-polymerase chain reaction (ChIP-PCR), yeast one-hybrid (Y1H), electrophoretic mobility shift assay (EMSA), and dual-luciferase (dual-LUC) analyses confirmed binding and transcriptional activation. Overexpressing BpDHN improved drought tolerance and ROS scavenging, while transient overexpression of BpAOS strengthened antioxidant activity and reduced membrane lipid peroxidation. Yeast two-hybrid (Y2H), bimolecular fluorescence complementation (BiFC), and luciferase complementation imaging further showed that BpERF1A and BpRAV1 form a heterodimer whose combined action activates the BpDHN promoter more strongly than either protein alone.

The authors said the findings reveal how a woody plant can connect stress sensing, gene control, antioxidant protection, and hormone-linked defense within one coordinated system. They said BpERF1A does more than switch on individual drought-response genes: by partnering with BpRAV1, it amplifies a protective program centered on dehydrin production and reactive oxygen species removal. In their view, this cooperation helps explain how perennial trees may sustain cellular protection during extended water shortage, while also identifying specific genes and protein interactions that can be tested systematically in future forest-breeding programs.

The BpERF1A-BpRAV1 regulatory module provides candidate targets for developing birch varieties better suited to dry, semi-arid, or degraded planting sites. In the longer term, the same strategy could guide marker-assisted selection, genomic selection, or carefully evaluated genetic engineering in other forest species, potentially improving plantation survival, ecological restoration, and timber stability under increasing drought pressure. The findings remain an experimental foundation rather than a ready-to-deploy forestry solution: performance must still be validated in mature trees, diverse genetic backgrounds, natural soils, and multi-year field conditions. Researchers will also need to examine growth trade-offs, water-use efficiency, environmental interactions, long-term stability, and regulatory requirements before practical application at scale.

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References

DOI

10.1093/hr/uhag133

Original Source URL

https://doi.org/10.1093/hr/uhag133

Funding information

This research was supported by the National Key Research and Development Program of China (2021YFD2200304).

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.