Analysis of differentially expressed transcripts of fungal elicitor- and wound-treated wild rice (Oryza grandiglumis)

Suppression subtractive hybridization was used to construct a subtracted library (ogfw) from plants of a wild rice species, Oryza grandiglumis, subjected to a fungal elicitor and physical wounding. To screen the differentially expressed transcripts in the library, we applied a reverse Northern blot analysis to a cDNA microarray containing 1,152 random clones. Based on the average expression ratio, we selected 156 clones showing an elevated expression level. The elevated expression levels and overall expression profiles over time were verified by Northern blot analysis. A comparative functional categorization of the subtracted expressed sequence tags (ESTs) of the ogfw library against ESTs isolated from blast-infected O. sativa showed that the functional categories of cell rescue, defense and virulence, transcription, and cellular transport and transport mechanism of the ogfw library were threefold higher in the former than in the latter. These subtracted ESTs can be presumed to be related to the defense/resistance system and will be used to investigate the defense mechanisms of wild rice and to provide new insights into the genome of wild rice, which in turn will assist molecular breeding strategies of cultivated rice.