Analysis of differential gene expression in potato leaves exposed to low dose ionizing radiation.

Land plants demonstrate high tolerance to acute ionizing radiation compared to other metazoans. However, few studies have analyzed plant gene expression in response to low-dose ionizing radiation. The present study performed two different sets of transcriptomic analysis of acutely exposed potato plants to 0.5-5 Gy of gamma radiation. In the first experiment, a total of 4,955 genes were differentially expressed in treated versus control plants. Among them, the gene expression of thirty-five genes were proportionally increased in a dose dependent manner. GO terms of these genes was enriched in DNA repair and metabolism related gene categories. Treatments caused no observable phenotypic effect until six weeks post-treatment, when apical growth aberrations led to an increase in lateral branching that corresponded with the total dose of gamma radiation. A second experiment analyzed the effect of shorter-duration exposures over the same dose range. While the shorter-duration exposures led to increased differentially expressed genes, thirty-one out of thirty-five genes identified in the first analysis were consistently expressed in this experiment. Also, the gene expression of these gene groups was reduced to baseline levels after recovery, indicating these genes are specific responsive genes against IR stress. Taken together, we identified DNA repair and metabolism related genes that were expressed at ~ 1 Gy of gamma radiation. These findings are important for future biotechnological studies to improve stress tolerance in plants, as well as, in the design of advanced potato phytosensors to report gamma radiation injuries.