Monitoring of radiation risk by sensitive genes of Tradescantia species

Some species of the genus Tradescantia are known to be sensitive to some environmental constraints. Exposure to ionizing radiation at doses of as low as 50 mGy can induce stamen hair color change to pink in the species, which might be a good biological indicator for monitoring radiation risk to humans. However, this perennial plant blooms within limited time periods, hence an alternative year-round monitoring system like genes sensitive to radiation leak from the related facility or instruments would be favourable. The objective of this study was to explore genes that respond to low radiation (˜max 1000 mGy) and to validate the monitoring value of the genes. A total of 77,326 representative transcripts were obtained from the RNA-seq data from 50, 250, 500, and 1000 mGy irradiation, among which 32,000 genes were annotated to public genes reported in 39 plant species. Gene ontology analysis indicated that the molecular functions of the differentially up-regulated genes involved monooxygenase, transferase, carbon-oxygen lyase, and hem binding. Many of the heat shock proteins were up-regulated at 50 mGy, including chaperon protein, HSPs, and calnexin. Also, two transcription factors [GLOBOSA (GLO), DEFICIENS (DEF)] involved in flower development, including the stamen hair, were cloned with 567 and 678 bp lengths. These genes were functionally validated and evaluated for their potential as monitoring genes for Tradescantia, detecting radiation damage to humans and to ecosystems.

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