A conserved transcript pattern in response to a specialist and a generalist herbivore

Area of Science:

• Plant molecular biology
• Plant-insect interactions
• Chemical ecology

Background:

• Plants exhibit distinct molecular responses to different types of attackers.
• Insect feeding and damage induce complex transcriptional changes in host plants.
• Understanding these plant defense mechanisms is crucial for agriculture and ecology.

Purpose of the Study:

• To characterize gene expression patterns in Arabidopsis thaliana leaves in response to the specialist insect Pieris rapae.
• To investigate the role of the jasmonate pathway in plant defense against insect attack.
• To compare transcriptional responses to specialist versus generalist insect herbivores.

Main Methods:

• Utilized a large-scale DNA microarray to analyze gene expression in damaged and distal Arabidopsis leaves.
• Employed jasmonate mutant analysis (coronatine insensitive1 glabrous1 - coi1-1 gl1) and exogenous jasmonate treatment.
• Compared transcript profiles induced by Pieris rapae (specialist) and Spodoptera littoralis (generalist) larvae.

Main Results:

• Identified over 100 insect-responsive genes, with 111 induced by Pieris feeding, primarily involved in defense pathways.
• Jasmonate signaling pathway controls 67-84% of Pieris-regulated gene expression, impacting larval performance.
• Transcriptional profiles elicited by specialist (P. rapae) and generalist (S. littoralis) insects were remarkably similar.

Conclusions:

• Arabidopsis thaliana exhibits a robust, jasmonate-dependent transcriptional defense response to insect herbivory.
• The plant's molecular response to insect attack shows limited discrimination between specialist and generalist herbivores.
• This study provides a valuable gene set for future research into plant-insect interactions and defense mechanisms.