Cassava gene MeFER4 found to heighten stress sensitivity in transgenic plants

While initially believed to enhance drought and oxidative stress tolerance, overexpression of MeFER4 in Arabidopsis led to increased sensitivity to multiple abiotic stresses, including drought, salinity, osmotic stress, and oxidative damage. The gene influenced reactive oxygen species (ROS) levels and altered the expression of key antioxidant enzymes. These findings suggest that MeFER4 plays a complex role in oxidative stress regulation and highlights the importance of fine-tuning gene expression for future crop improvement strategies targeting stress resilience.

Abiotic stresses such as drought, salinity, and oxidative damage threaten global crop yields, especially in regions where staple crops like cassava are vital for food security. One key factor in stress tolerance is the regulation of ROS, which accumulate under stress and damage cellular structures. Ferritin proteins, known for iron storage, also contribute to ROS homeostasis by limiting iron-catalyzed ROS formation. In cassava, the MeFER4 gene encodes a ferritin-like protein and has been previously associated with stress markers. However, the exact function of MeFER4 in stress adaptation remained unclear. Due to these challenges, it is essential to conduct detailed investigations into the molecular pathways governed by MeFER4.

A study (DOI: 10.48130/tp-0025-0010) published in Tropical Plants on 03 April 2025 by Wenquan Wang, Xiaohui Yu & Xin Guo’s team, Hainan University, opens new avenues for developing stress-resilient crops by targeting ROS homeostasis pathways.

In this study, researchers employed a suite of molecular and physiological techniques to investigate the role of the cassava ferritin-like gene MeFER4 in regulating plant stress responses. MeFER4 was first mapped to Chromosome 8 of the cassava genome, where structural analysis revealed conserved ferritin domains linked to iron storage and oxidative stress control. Genome-wide association studies (GWAS) connected MeFER4 to key drought-related traits, including malondialdehyde (MDA), proline, and antioxidant enzyme activities. Expression profiling showed that MeFER4 is upregulated in cassava leaves under drought conditions and is localized in the chloroplast. To further probe its function, the researchers generated Arabidopsis lines overexpressing MeFER4. These transgenic lines exhibited significantly increased sensitivity to drought stress, showing greater wilting, reduced survival rates, and higher ROS accumulation. The overexpression lines also displayed hypersensitivity to abscisic acid (ABA), H₂O₂, and methyl viologen, with consistently elevated ROS levels and altered expression of stress-related genes. Notably, under salinity and osmotic stress, MeFER4-overexpressing plants showed severe leaf damage and disrupted expression of transcription factors and antioxidant genes. Molecular assays, including yeast two-hybrid, split-luciferase complementation, and BiFC, confirmed that MeFER4 physically interacts with key antioxidant enzymes APX1 and APX3. These findings suggest that MeFER4 modulates redox balance by forming complexes with ROS-scavenging enzymes. However, overexpression disrupts this balance, amplifying oxidative stress signals and compromising stress tolerance. The study reveals MeFER4 as a complex regulator of abiotic stress responses and underscores the need for precise modulation of its activity in future crop improvement efforts.

While MeFER4 was initially considered a candidate gene for improving drought tolerance in cassava, its overexpression in Arabidopsis revealed risks associated with disrupting antioxidant defenses. Moving forward, fine-tuning MeFER4 expression—either through tissue-specific promoters or inducible systems—may help achieve stress resilience without compromising plant health. This work highlights the intricate trade-offs in engineering plant stress tolerance and underscores the need for precise genetic strategies.

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References

DOI

10.48130/tp-0025-0010

Original Source URL

https://doi.org/10.48130/tp-0025-0010

Funding information

This research was supported by the Hainan Provincial Natural Science Foundation of China (324MS122), the National Natural Science Foundation of China (32360458), the startup funds for the Hainan University E-class Talents (XJ2300007513), and the China Agriculture Research System (CARS-11-HNCYH), both of which made this research possible.

About Tropical Plants

Tropical Plants (e-ISSN 2833-9851) is the official journal of Hainan University and published by Maximum Academic Press. Tropical Plants undergoes rigorous peer review and is published in open-access format to enable swift dissemination of research findings, facilitate exchange of academic knowledge and encourage academic discourse on innovative technologies and issues emerging in tropical plant research.