Boosting Tomato Plant Defenses Against Pests with Phenylalanine

Jim Crocker
8th April, 2024

Boosting Tomato Plant Defenses Against Pests with Phenylalanine

Image Source: Natural Science News, 2024

Key Findings

  • In a study by The Volcani Center, tomato plants treated with phenylalanine resisted the pest Tuta absoluta
  • Treated plants emitted specific volatiles that repelled the leafminer and protected nearby untreated plants
  • This method could offer a sustainable alternative to chemical pesticides in agriculture
In the ongoing battle between farmers and pests, the tomato plant has found itself in a particularly tough spot. The leafminer, Tuta absoluta, is a notorious pest that wreaks havoc on tomato crops across the globe. Traditional chemical pesticides have been the go-to solution, but they are losing their effectiveness as the leafminer rapidly develops resistance. In a groundbreaking study by the Agricultural Research Organization, The Volcani Center[1], scientists have discovered a new way to bolster tomato plants' defenses against this resilient insect. The study found that when tomato plants are treated with solutions of phenylalanine, an amino acid, they become highly resistant to the leafminer. This resistance was consistent across various tomato cultivars, in different environments from greenhouses to open fields, and in multiple geographic locations. The key to this enhanced defense lies in the plant's volatile profile, which changes when phenylalanine is absorbed and metabolized by the tomato leaves. The altered volatile profile is characterized by an increase in three specific benzenoid phenylpropanoid volatiles (BPVs): benzaldehyde, phenylacetaldehyde, and 2-phenylethanol. These BPVs are derivatives of phenylalanine and are known for their repellent properties against pests like the leafminer. Interestingly, this phenylalanine treatment did not affect other volatiles such as terpenes and green leaf volatiles, which also play a role in plant defense. Moreover, the study revealed a remarkable phenomenon: Phe-treated plants could boost the resistance of neighboring, untreated plants. RNA sequencing analysis of these neighboring plants showed an upregulation of genes associated with the plant immune response system. This suggests that the BPVs not only repel pests but also trigger a systemic immune response in surrounding tomato plants. This finding builds on previous research where Bacillus fortis IAGS162 was shown to induce systemic resistance in tomato plants against Fusarium wilt disease through the release of phenylacetic acid (PAA), an ISR determinant[2]. The current study expands on this by demonstrating that phenylalanine-derived BPVs can also mediate plant-insect interactions by inducing defense mechanisms. The study's metabolomic analysis provides a comprehensive view of how external application of phenylalanine can reprogram a plant's metabolic networks, a concept supported by earlier findings on the dynamic reprogramming of plant pathways in response to ISR elicitors[2]. This reprogramming leads to an effective and sustainable defense strategy that could potentially reduce the reliance on chemical pesticides. Furthermore, the study's insights into volatile organic compounds (VOCs) and their role in plant-plant interactions resonate with previous research on how VOCs emitted by plants can affect the growth and reproduction of receiver plants[3]. The current research adds to this by showing that specific VOCs can also play a critical role in plant defense against herbivores. In summary, the research from The Volcani Center offers a promising alternative to chemical pesticides by using phenylalanine to trigger a natural defense mechanism in tomatoes against the leafminer. This approach not only repels the pest but also activates the immune response in both treated and neighboring untreated plants. As we move towards more sustainable agricultural practices, such strategies that harness the plant's own defense systems could be key in managing pests and ensuring food security.

BiochemPlant ScienceAgriculture

References

Main Study

1) Phenylalanine treatment induces tomato resistance to Tuta absoluta via increased accumulation of benzenoid/phenylpropanoid volatiles serving as defense signals.

Published 5th April, 2024

https://doi.org/10.1111/tpj.16745

Related Studies

2) Phenylacetic Acid Is ISR Determinant Produced by Bacillus fortis IAGS162, Which Involves Extensive Re-modulation in Metabolomics of Tomato to Protect against Fusarium Wilt.

https://doi.org/10.3389/fpls.2016.00498

3) Volatile-mediated plant-plant interactions: volatile organic compounds as modulators of receiver plant defence, growth, and reproduction.

https://doi.org/10.1093/jxb/erab487


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