Maize genes induced by herbivory and volicitin

Area of Science:

• Plant Science
• Entomology
• Biochemistry

Background:

• Mechanical damage and insect attack induce gene transcription changes in plants.
• Understanding insect herbivory's specificity is crucial for pest-host interactions.

Purpose of the Study:

• To investigate if insect herbivory elicits a unique plant response compared to general wounding.
• To determine the specificity of plant responses to pest/host plant interactions.

Main Methods:

• Comparing gene expression changes induced by beet armyworm (BAW) feeding versus mechanical wounding alone.
• Utilizing volicitin, a component of BAW oral secretions, to mimic caterpillar-induced volatile emission.
• Employing subtractive libraries and reverse northern blots to identify differentially expressed genes.
• Confirming gene expression patterns with virtual northern blots.

Main Results:

• BAW herbivory on maize produces unique volatile compounds, distinct from wounding alone, attracting parasitoids.
• Volicitin application to wounded leaves mimics caterpillar-induced volatile emission.
• BAW feeding and volicitin treatment affect gene expression, with some genes inhibited by feeding, suggesting additional oral secretion components.
• Genes involved in volatile production are upregulated by volicitin and BAW infestation.
• Three new sesquiterpene cyclase genes were identified as being induced by volicitin.

Conclusions:

• Insect herbivory induces a specific plant response involving unique volatile compounds and gene expression patterns.
• Volicitin is a key component in triggering plant defense volatile production.
• Maize gene expression is modulated by BAW feeding, with potential roles for additional factors in caterpillar regurgitate.