Transcriptome profiling and physiological studies reveal a major role for aromatic amino acids in mercury stress tolerance in rice seedlings.
Mercury (Hg) is a serious environmental pollution threat to the planet. The accumulation of Hg in plants disrupts many cellular-level functions and inhibits growth and development, but the mechanism is not fully understood. To gain more insight into the cellular response to Hg, we performed a large-scale analysis of the rice transcriptome during Hg stress. Genes induced with short-term exposure represented functional categories of cell-wall formation, chemical detoxification, secondary metabolism, signal transduction and abiotic stress response. Moreover, Hg stress upregulated several genes involved in aromatic amino acids (Phe and Trp) and increased the level of free Phe and Trp content. Exogenous application of Phe and Trp to rice roots enhanced tolerance to Hg and effectively reduced Hg-induced production of reactive oxygen species. Hg induced calcium accumulation and activated mitogen-activated protein kinase. Further characterization of the Hg-responsive genes we identified may be helpful for better understanding the mechanisms of Hg in plants.
Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan, ROC; Department of Biological Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan, ROC.
Yun-An
YA
Chen
Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan, ROC.
Wen-Chang
WC
Chi
Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan, ROC.
Ngoc Nam
NN
Trinh
Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan, ROC.
Li-Yao
LY
Huang
Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan, ROC.
Ying-Chih
YC
Chen
Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan, ROC.
Kai-Teng
KT
Cheng
Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan, ROC.
Tsai-Lien
TL
Huang
Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan, ROC.
Chung-Yi
CY
Lin
Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan, ROC.
Hao-Jen
HJ
Huang
D024322:Amino Acids, Aromatic / Q000378:metabolism*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000235:genetics; D008628:Mercury / Q000633:toxicity*; D012275:Oryza / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics; D036226:Seedlings / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*
D024322:Amino Acids, Aromatic; D010940:Plant Proteins; D008628:Mercury