Poster: Plant-symbiont interactions

Abs # 597: Root Nodule-Enhanced Transcriptome analysis from Soybean

Presenter:	Lee, Hyoungseok , soulaid2@snu.ac.kr
Authors	Lee, Hyoungseok  (A)   Hur, Cheol-Goo  (B)   Oh, Chang Jae  (A)   Kim, Ho Bang  (A)   Park, Sunyong  (B)   An, Chung Sun  (A)
Affiliations:	(A): School of Biological Sciences, Seoul National University (B): 1Korea Research Institute Bioscience and Biotechnology, Genome Research Center

For the high throughput screening of root nodule-enhanced genes, three cDNA libraries specific for the root nodule of soybean were constructed from three different stages of root nodules after inoculation with Bradyrhizobium japonicum USDA110. From these cDNA libraries, 5,469 cDNA clones were sequenced and clustered into 2,511 non-redundant ESTs comprised of 769 contigs and 1,742 singletons. Using similarity searches against several public databases, we could make the functional catalog of our ESTs, including several nodule specific genes named nodulin genes, various stress-responsive genes, genes related to carbon and to nitrogen metabolism. Also, the cDNA microarray was constructed with selected 382 clones that were assumed to be up-regulated in the nodule. Using a 382-cDNA clone microarray, we have compared transcripts level from the root and from the root nodule from four different developmental stages, i.e., the root at 4 days after inoculation (DAI), the root nodule at 10 DAI, at 5 weeks after inoculation (WAI), and at 10 WAI, respectively. A total of 81 genes differentially expressed in these experiments were grouped into seven clusters according to the similarity of their expression profiles using a hierarchical clustering algorithm. Among them, cluster 1, 2, 3, and 6, comprised of 58 genes, showed nodule-enhanced expression. The information from this study will be used for further study on the functional roles of nodule specific genes and the signaling network of them during the root nodule development.