Boosting Tomato Genes Helps Plants Handle Cadmium by Managing Metal and Hormones

Jim Crocker
25th June, 2024

Boosting Tomato Genes Helps Plants Handle Cadmium by Managing Metal and Hormones

Image Source: Natural Science News, 2024

Key Findings

  • The study from Harbin Normal University and Heilongjiang Academy of Agricultural Sciences focused on how plants withstand cadmium (Cd) stress
  • Two specific genes in tomatoes, SlJMJ18 and SlJMJ23, were found to respond to heavy metal stress, including Cd
  • Overexpressing SlJMJ18 in plants led to Cd resistance and early flowering, while SlJMJ23 overexpression showed Cd sensitivity initially but greater tolerance later
  • These genes may help plants tolerate Cd by regulating hormone synthesis and increasing phenol content
Cadmium (Cd) is a hazardous element that poses significant risks to plant growth and human health. It is a non-essential element for plants, and even at lower concentrations, Cd can have deleterious effects. Recent research from Harbin Normal University and Heilongjiang Academy of Agricultural Sciences has provided new insights into how plants can withstand Cd stress by focusing on the role of histone demethylase (JHDM) genes[1]. Histone demethylases are enzymes that modify histones, proteins around which DNA is wrapped, thereby influencing gene expression. The study specifically investigated two JHDM genes in tomatoes, SlJMJ18 and SlJMJ23. The expression levels of these genes were evaluated in different tomato tissues under stress from various heavy metals, including Cd, Hg, Pb, and Cu. The findings revealed that both genes were responsive to these stresses, as confirmed by fluorescence quantification and GUS staining techniques. Interestingly, the overexpression of these genes in transgenic Arabidopsis plants showed different responses to Cd stress. The SlJMJ18 overexpression (SlJMJ18-OE) lines consistently displayed Cd resistance but also exhibited an early-flowering phenotype. In contrast, SlJMJ23 overexpression (SlJMJ23-OE) plants were sensitive during the post-germination stage but demonstrated greater tolerance to Cd stress later on. This differential response suggests that these genes play distinct roles in Cd tolerance. The study found that these genes might influence Cd tolerance by regulating the expression of hormone synthesis-related genes and hormone contents, specifically brassinosteroids (BRs) and abscisic acid (ABA). Additionally, SlJMJ23 was found to increase the total phenol content in plants, which may contribute to its role in resisting Cd stress. These findings build on earlier research about Cd's impact on plants. For example, a study on Vicia sativa showed that Cd treatment decreased plant growth and increased reactive oxygen species (ROS) and lipid peroxidation levels, particularly in Cd-sensitive varieties[2]. This earlier study also highlighted the role of lignification and antioxidant enzymatic activity in Cd tolerance. Similarly, the current research underscores the importance of specific genetic factors in enhancing Cd tolerance. Another relevant study discussed the uptake and detoxification mechanisms for heavy metals like Cd and arsenic in plants[3]. This study highlighted the similarities in the toxicology and sequestration machineries for these metals, providing a broader context for understanding how plants manage heavy metal stress. The new research adds to this understanding by identifying specific genes that can be targeted for developing Cd-resistant plants. Moreover, the role of PIB-type ATPases, such as HMA2, in transporting heavy metals across biological membranes has been well-documented[4]. HMA2 is involved in the efflux of Zn2+ and Cd2+ from the cell cytoplasm, maintaining low cytoplasmic levels of these metals. The current study complements this by showing how histone demethylase genes can regulate hormone synthesis and phenol content, providing another layer of complexity in the plant's response to Cd stress. In summary, the research from Harbin Normal University and Heilongjiang Academy of Agricultural Sciences provides valuable insights into the role of histone demethylase genes in Cd tolerance. By understanding how SlJMJ18 and SlJMJ23 regulate hormone synthesis and phenol content, scientists can develop new strategies for creating Cd-resistant plants. This study not only advances our knowledge of plant stress responses but also offers practical applications for improving agricultural productivity and environmental sustainability in Cd-contaminated areas.

GeneticsBiochemPlant Science

References

Main Study

1) Overexpression of Histone Demethylase Gene SlJMJ18 and SlJMJ23 from Tomato Confers Cadmium Tolerance by Regulating Metal Transport and Hormone Synthesis in Arabidopsis.

Published 22nd June, 2024

https://doi.org/10.1016/j.plantsci.2024.112169

Related Studies

2) Cd-induced oxidative stress and lignification in the roots of two Vicia sativa L. varieties with different Cd tolerances.

https://doi.org/10.1016/j.jhazmat.2015.08.052

3) Mechanisms to cope with arsenic or cadmium excess in plants.

https://doi.org/10.1016/j.pbi.2009.05.001

4) Arabidopsis HMA2, a divalent heavy metal-transporting P(IB)-type ATPase, is involved in cytoplasmic Zn2+ homeostasis.

Journal: Plant physiology, Issue: Vol 136, Issue 3, Nov 2004


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