How Azelaic Acid Helps Tomatoes Resist Fungal Infections

Greg Howard
19th July, 2024

How Azelaic Acid Helps Tomatoes Resist Fungal Infections

Treatment with azelaic acid significantly reduced the severity of disease in tomato (Solanum lycopersicum) plants infected with the fungus Alternaria solani, demonstrating its ability to induce resistance.

Image adapted from: Haghpanah et al. / CC BY (Source)

Key Findings

  • Researchers in Iran studied how azelaic acid (Aza) affects tomato plants' defense against the fungal disease early blight
  • Aza-treated tomato plants showed increased activity of enzymes that reduce oxidative stress, helping them manage harmful reactive oxygen species better than untreated plants
  • Aza treatment enhanced the expression of key defense genes, boosting the plant's immune response through complex interactions between different signaling pathways
Tomato plants, a vital crop worldwide, often face significant challenges from fungal diseases, including early blight caused by Alternaria solani. Researchers at the Agricultural Research, Education and Extension Organization (AREEO), Iran, have investigated the impact of azelaic acid (Aza) on tomato plant responses to A. solani infection[1]. This study's findings could pave the way for more effective disease management strategies, enhancing tomato crop resilience and productivity. In this study, tomato plants were treated with Aza before being infected with A. solani. The researchers then analyzed the plants' antioxidant, biochemical, and molecular responses to understand how Aza influences disease resistance. The results revealed that Aza-treated plants exhibited notable changes in their defense mechanisms compared to untreated, control plants. One of the key findings was the increase in peroxidase (POD) and catalase (CAT) activities in Aza-treated plants during the early stages of A. solani infection. These enzymes play crucial roles in mitigating oxidative stress by breaking down harmful reactive oxygen species (ROS) like hydrogen peroxide (H2O2). In control plants, H2O2 and malondialdehyde (MDA) levels rose significantly after pathogen infection, indicating increased oxidative damage. However, in Aza-treated plants, the enhanced POD and CAT activities helped manage ROS levels more effectively, reducing oxidative stress and damage. The study also explored gene expression changes induced by Aza treatment and pathogen infection. Notably, the expression of SlPDF1.2, a marker gene for the jasmonic acid/ethylene (JA/ET) signaling pathway, increased 4.2-fold upon pathogen infection. This suggests that Aza primes the JA/ET pathway, enhancing the plant's defense against A. solani. Additionally, the expression of SlNPR1, a key gene in the salicylic acid (SA) pathway, showed a delayed increase at 96 hours post-infection (hpi). This delay indicates a complex interplay between the JA and SA pathways in response to Aza treatment. Phytohormone analysis further supported these findings. In Aza-treated plants, JA levels increased following pathogen infection, while SA accumulation was significantly higher in plant tissues with disease development. This dual modulation of the SA and JA pathways underscores the multifaceted nature of Aza-induced resistance. These results align with previous studies highlighting the role of various compounds in enhancing plant immunity. For instance, β-Aminobutyric acid (BABA) has been shown to increase nitric oxide (NO) accumulation, boosting resistance against Botrytis cinerea in tomato plants[2]. Similarly, potassium phosphite (KPhi) has been found to prime potato plants for a more robust defense response against Phytophthora infestans by enhancing hydrogen peroxide and superoxide anion production[3]. Both studies emphasize the importance of priming plant defense mechanisms through biochemical and molecular changes. The current study's findings contribute to the growing body of knowledge on systemic acquired resistance (SAR) in plants. By elucidating the mechanisms through which Aza modulates SA and JA pathways, this research provides valuable insights into developing more effective strategies for managing fungal diseases in tomato crops. The integration of such findings with existing knowledge on plant immunity could lead to the development of tomato cultivars with enhanced resistance to multiple pathogens, ultimately improving crop yield and sustainability.

AgricultureBiochemPlant Science

References

Main Study

1) New insights into azelaic acid-induced resistance against Alternaria Solani in tomato plants.

Published 19th July, 2024

https://doi.org/10.1186/s12870-024-05397-7

Related Studies

2) Nitric Oxide Plays an Important Role in β-Aminobutyric Acid-Induced Resistance to Botrytis cinerea in Tomato Plants.

https://doi.org/10.5423/PPJ.OA.11.2019.0274

3) Potassium phosphite primes defense responses in potato against Phytophthora infestans.

https://doi.org/10.1016/j.jplph.2012.05.005


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