Genomics of hybrid poplar (Populus trichocarpax deltoides) interacting with forest tent caterpillars (Malacosoma disstria): normalized and full-length cDNA libraries, expressed sequence tags, and a cDNA microarray for the study of insect-induced defences in poplar.
As part of a genomics strategy to characterize inducible defences against insect herbivory in poplar, we developed a comprehensive suite of functional genomics resources including cDNA libraries, expressed sequence tags (ESTs) and a cDNA microarray platform. These resources are designed to complement the existing poplar genome sequence and poplar (Populus spp.) ESTs by focusing on herbivore- and elicitor-treated tissues and incorporating normalization methods to capture rare transcripts. From a set of 15 standard, normalized or full-length cDNA libraries, we generated 139,007 3'- or 5'-end sequenced ESTs, representing more than one-third of the c. 385,000 publicly available Populus ESTs. Clustering and assembly of 107,519 3'-end ESTs resulted in 14,451 contigs and 20,560 singletons, altogether representing 35,011 putative unique transcripts, or potentially more than three-quarters of the predicted c. 45,000 genes in the poplar genome. Using this EST resource, we developed a cDNA microarray containing 15,496 unique genes, which was utilized to monitor gene expression in poplar leaves in response to herbivory by forest tent caterpillars (Malacosoma disstria). After 24 h of feeding, 1191 genes were classified as up-regulated, compared to only 537 down-regulated. Functional classification of this induced gene set revealed genes with roles in plant defence (e.g. endochitinases, Kunitz protease inhibitors), octadecanoid and ethylene signalling (e.g. lipoxygenase, allene oxide synthase, 1-aminocyclopropane-1-carboxylate oxidase), transport (e.g. ABC proteins, calreticulin), secondary metabolism [e.g. polyphenol oxidase, isoflavone reductase, (-)-germacrene D synthase] and transcriptional regulation [e.g. leucine-rich repeat transmembrane kinase, several transcription factor classes (zinc finger C3H type, AP2/EREBP, WRKY, bHLH)]. This study provides the first genome-scale approach to characterize insect-induced defences in a woody perennial providing a solid platform for functional investigation of plant-insect interactions in poplar.
Ralph
Steven
S
Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada, V6T 1Z3.
Oddy
Claire
C
Cooper
Dawn
D
Yueh
Hesther
H
Jancsik
Sharon
S
Kolosova
Natalia
N
Philippe
Ryan N
RN
Aeschliman
Dana
D
White
Rick
R
Huber
Dezene
D
Ritland
Carol E
CE
Benoit
François
F
Rigby
Tracey
T
Nantel
André
A
Butterfield
Yaron S N
YS
Kirkpatrick
Robert
R
Chun
Elizabeth
E
Liu
Jerry
J
Palmquist
Diana
D
Wynhoven
Brian
B
Stott
Jeffrey
J
Yang
George
G
Barber
Sarah
S
Holt
Robert A
RA
Siddiqui
Asim
A
Jones
Steven J M
SJ
Marra
Marco A
MA
Ellis
Brian E
BE
Douglas
Carl J
CJ
Ritland
Kermit
K
Bohlmann
Jörg
J
D000818:Animals; D018076:DNA, Complementary / Q000235:genetics; D004798:Enzymes / Q000235:genetics; D019143:Evolution, Molecular; D020224:Expressed Sequence Tags; D015723:Gene Library; D005838:Genotype; D019476:Insect Proteins / Q000235:genetics; D007915:Lepidoptera / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity; D009693:Nucleic Acid Hybridization; D020411:Oligonucleotide Array Sequence Analysis; D010935:Plant Diseases / Q000382:microbiology; D032107:Populus / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology; D014158:Transcription, Genetic
D018076:DNA, Complementary; D004798:Enzymes; D019476:Insect Proteins