Characterization of de novo transcriptome for waterhemp (Amaranthus tuberculatus) using GS-FLX 454 pyrosequencing and its application for studies of herbicide target-site genes.
BACKGROUND
Waterhemp is a model for weed genomics research in part because it possesses many interesting biological characteristics, rapidly evolves resistance to herbicides and has a solid foundation of previous genetics work. To develop further the genomics resources for waterhemp, the transcriptome was sequenced using Roche GS-FLX 454 pyrosequencing technology.


RESULTS
Pyrosequencing produced 483 225 raw reads, which, after quality control and assembly, yielded 44 469 unigenes (contigs + singletons). A total of 49% of these unigenes displayed highly significant similarities to Arabidopsis proteins and were subsequently grouped into gene ontology categories. Blast searches against public and custom databases helped in identifying and obtaining preliminary sequence data for all of the major target-site genes for which waterhemp has documented resistance. Moreover, sequence data for two other herbicide targets [4-hydroxyphenylpyruvate dioxygenase (HPPD) and glutamine synthetase], where resistance has not yet been reported in any plant, were also investigated in waterhemp and six related weedy Amaranthus species.


CONCLUSIONS
These results demonstrate the enormous value of 454 sequencing for gene discovery and polymorphism detection in a major weed species and its relatives. Furthermore, the merging of the 454 transcriptome data with results from a previous whole genome 454 sequencing experiment has made it possible to establish a valuable genomic resource for weed science research.
Riggins
Chance W
CW
Department of Crop Sciences, University of Illinois, Urbana, IL, USA.
Peng
Yanhui
Y
Stewart
C Neal
CN
Tranel
Patrick J
PJ
D027721:Amaranthus / Q000187:drug effects / Q000235:genetics*; D015870:Gene Expression / Q000187:drug effects; D020869:Gene Expression Profiling; D006540:Herbicides / Q000494:pharmacology*; D010940:Plant Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA / Q000379:methods*
D006540:Herbicides; D010940:Plant Proteins