Different transcript patterns in response to specialist and generalist herbivores in the wild Arabidopsis relative Boechera divaricarpa.
BACKGROUND
Plants defend themselves against herbivorous insects, utilizing both constitutive and inducible defenses. Induced defenses are controlled by several phytohormone-mediated signaling pathways. Here, we analyze transcriptional changes in the North American Arabidopsis relative Boechera divaricarpa in response to larval herbivory by the crucifer specialist lepidopteran Plutella xylostella (diamondback moth) and by the generalist lepidopteran Trichoplusia ni (cabbage semilooper), and compare them to wounding and exogenous phytohormone application.


RESULTS
We use a custom macroarray constructed from B. divaricarpa herbivory-regulated cDNAs identified by suppression subtractive hybridization and from known stress-responsive A. thaliana genes for transcript profiling after insect herbivory, wounding and in response to jasmonate, salicylate and ethylene. In addition, we introduce path analysis as a novel approach to analyze transcript profiles. Path analyses reveal that transcriptional responses to the crucifer specialist P. xylostella are primarily determined by direct effects of the ethylene and salicylate pathways, whereas responses to the generalist T. ni are influenced by the ethylene and jasmonate pathways. Wound-induced transcriptional changes are influenced by all three pathways, with jasmonate having the strongest effect.


CONCLUSIONS
Our results show that insect herbivory is distinct from simple mechanical plant damage, and that different lepidopteran herbivores elicit different transcriptional responses.
Vogel
Heiko
H
Department of Genetics and Evolution, Max Planck Institute for Chemical Ecology, Jena, Germany.
Kroymann
Juergen
J
Mitchell-Olds
Thomas
T
D000818:Animals; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism*; D018076:DNA, Complementary / Q000378:metabolism; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D008954:Models, Biological; D009036:Moths; D009693:Nucleic Acid Hybridization; D020411:Oligonucleotide Array Sequence Analysis; D010935:Plant Diseases; D010937:Plant Growth Regulators; D018521:Plant Physiological Phenomena; D012333:RNA, Messenger / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D015398:Signal Transduction
D018076:DNA, Complementary; D010937:Plant Growth Regulators; D012333:RNA, Messenger