Location: Children's Nutrition Research CenterTitle: Ectopic expression of Arabidopsis glutaredoxin AtGRXS17 enhances thermotolerance in tomato) Author
Submitted to: Plant Biotechnology Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/25/2012
Publication Date: 7/5/2012
Citation: Wu, Q., Lin, J., Liu, J., Wang, X., Lim, W., Oh, M., Park, J., Rakasjelar, C., Whitham, S.A., Cheng, N., Hirschi, K.D., Park, S. 2012. Ectopic expression of Arabidopsis glutaredoxin AtGRXS17 enhances thermotolerance in tomato. Plant Biotechnology Journal. 945-955. Interpretive Summary: Agricultural productivity and food production are encountering multifaceted challenges from global climate changes, and extensive agricultural losses are attributed to heat and drought. This study demonstrated that introducing a gene, encoding a protein to attenuate stress levels within the cells, could enhance heat tolerance and keep crop growth robust under extreme conditions. Therefore, these findings open a new avenue for genetically modified organisms to improve crops and impact food production.
Technical Abstract: While various signaling networks regulate plant responses to heat stress, the mechanisms regulating and unifying these diverse biological processes are largely unknown. Our previous studies indicate that the Arabidopsis monothiol glutaredoxin, AtGRXS17, is crucial for temperature-dependent postembryonic growth in Arabidopsis. In the present study, we further demonstrate that AtGRXS17 has conserved functions in anti-oxidative stress and thermotolerance in both yeast and plants. In yeast, AtGRXS17 co-localized with yeast ScGrx3 in the nucleus and suppressed the sensitivity of yeast grx3grx4 double-mutant cells to oxidative stress and heat shock. In plants, GFP-AtGRXS17 fusion proteins initially localized in the cytoplasm and the nuclear envelope but migrated to the nucleus during heat stress. Ectopic expression of AtGRXS17 in tomato plants minimized photo-oxidation of chlorophyll and reduced oxidative damage of cell membrane systems under heat stress. This enhanced thermotolerance correlated with increased catalase (CAT) enzyme activity and reduced H2O2 accumulation in AtGRXS17-expressing tomatoes. Furthermore, during heat stress, expression of the heat shock transcription factor (HSF) and heat shock protein (HSP) genes was up-regulated in AtGRXS17-expressing transgenic plants compared with wild-type controls. Thus, these findings suggest a specific protective role of a redox protein against temperature stress and provide a genetic engineering strategy to improve crop thermotolerance.