Poster: Plant-symbiont interactions

Abs # 588: Transcript Profiling of Early Interactions between Rhizobia and Medicago truncatula

Presenter:	Lohar, Dasharath P., lohar001@umn.edu
Authors	Lohar, Dasharath P. (A)   Sharopova, Natalya  (A)   Endre, Gabriella  (B)   Dickson, Mark  (A)   VandenBosch, Kathryn  (A)
Affiliations:	(A): University of Minnesota (B): Hungarian Academy of Sciences

A cDNA microarray containing 6144 elements was constructed using tentative consensus sequences (TCs) and Minnesota contigs (MNCs) from the Medicago truncatula expressed sequence tag (EST) database. Each microarray was hybridized to cDNAs from both inoculated (with Sinorhizobium meliloti) and uninoculated wild type M. truncatula roots, along a time course spanning 6 to 72 hours post inoculation (hpi). These time points correspond to events in early Nod factor responses through infection of nodule primordia. Each hybridization was repeated a total of 6 times to control for technical variability. For each hybridization, the raw intensities were normalized using LOWESS and ANOVA, and the statistical significance of the difference between the intensities was calculated. Some of the significantly up-regulated genes were those already known to be expressed at higher levels in inoculated roots of M. truncatula. However, a large number of new genes were also found to be differentially regulated in inoculated and uninoculated roots, including many of unknown function. An analysis of the patterns of differential gene expression upon rhizobial inoculation will be presented. We gratefully acknowledge support from the NSF Plant Genome Project (award #0110206).