A herbivore that manipulates plant defence

Area of Science:

• Plant-herbivore interactions
• Plant immunology
• Invasive species ecology

Background:

• Phytopathogens and herbivores trigger plant defense mechanisms.
• While pathogen-induced defense suppression is documented, herbivore-induced suppression is less understood.
• Investigating herbivore strategies to overcome plant defenses is crucial for understanding plant resistance.

Purpose of the Study:

• To investigate the effect of the invasive spider mite Tetranychus evansi on tomato plant defense signaling pathways.
• To determine if T. evansi suppresses induced plant defenses, similar to some pathogens.
• To understand the implications of this suppression for mite performance and plant resistance.

Main Methods:

• Measuring salicylic acid and jasmonic acid signaling pathways in mite-infested tomato plants.
• Quantifying levels of inducible defense compounds, such as proteinase inhibitors.
• Assessing the release of inducible volatile organic compounds.
• Comparing mite performance on previously attacked versus non-attacked plants.

Main Results:

• Tetranychus evansi significantly suppressed the induction of salicylic acid and jasmonic acid signaling pathways in tomato.
• Inducible defense compounds were reduced below constitutive levels in mite-infested plants.
• The release of inducible plant defense volatiles was suppressed by the spider mite.
• Mites performed significantly better on previously attacked tomato plants.

Conclusions:

• The invasive spider mite Tetranychus evansi actively suppresses tomato plant defenses.
• This suppression involves interference with key defense signaling pathways and reduced production of defense compounds and volatiles.
• These findings offer new insights into plant-herbivore interactions, invasive species, and strategies for plant protection.