ARS | Publication request: EXPRESSED SEQUENCE TAGS OF ONION FOR COMPARATIVE MAPPING AND PHYGENETIC ANALYSES OF THE ASPARAGALES

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: December 15, 2002
Publication Date: January 15, 2003
Citation: Havey, M.J., Jenderek, M.M., Sink, K., Cheung, F., Town, C. 2003. Expressed sequence tags of onion for comparative mapping and phygenetic analyses of the asparagales. Meeting Abstract. Proceedings of Monocots III

Technical Abstract: Enormous genomic resources are being developed for model plants such as Arabidopsis thaliana and rice. However, it is not clear how broadly these genomic resources can be applied to the genetic improvement of related crops. Onion (Allium cepa) is the most economically important vegetable of the monocot order Asparagales, followed by garlic (A. sativum) and asparagus (Asparagus officinalis). The orders Asparagales and Poales represent two distinct monophyletic groups in the monocots. A salient question is whether the genomic resources developed for rice or other crops of the Poales will be applicable to the Asparagales. We synthesized a normalized cDNA library of onion from equal molar amounts of mRNA from callus, immature bulbs, and roots. A total of 20,000 single pass sequencing reactions yielded 11,008 unique ESTs assembling into 3,690 clusters and 7,318 singletons, at least twice the number expected from a non-normalized library. We chose onion ESTs showing highly significant homologies to rice ESTs present only once in the rice nuclear genome. These onion ESTs will be used for comparative mapping of asparagus, garlic, and onion with the Poales. If little synteny existed between the Asparagales and Poales, a model genomic resource should be developed from a relatively small-genomed Asparagales species.