Wei Wei Chen1, Jian Feng Jin2, He Qiang Lou3, Li Liu4, Leon V Kochian4, Jian Li Yang5. 1. Research Centre for Plant RNA Signaling, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, China. 2. State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China. 3. State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Lin'an, 311300, Zhejiang, China. 4. Global Institute for Food Security, University of Saskatchewan, Saskatoon, SK, S7N 4J8, Canada. 5. State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China. yangjianli@zju.edu.cn.
Abstract
MAIN CONCLUSION: An SPL-type transcription factor, LeSPL-CNR, is negatively involved in NO production by modulating SlNR expression and nitrate reductase activity, which contributes to Cd tolerance. Cadmium (Cd) is a highly toxic pollutant. Identifying factors affecting Cd accumulation in plants is a prerequisite for minimizing dietary uptake of Cd from crops grown with contaminated soil. Here, we report the involvement of a SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE (SPL) transcription factor LeSPL-CNR in Cd tolerance in tomato (Solanum lycopersicum). In comparison with the wild-type Ailsa Craig (AC) plants, the Colourless non-ripening (Cnr) epimutant displayed increased Cd accumulation and enhanced sensitivity to Cd, which was in well accordance with the repression of LeSPL-CNR expression. Cd stress-induced NO production was inhibited by nitrate reductase (NR) inhibitor, but not NO synthase-like enzyme inhibitor. Expression of LeSPL-CNR was negatively correlated with SlNR expression and the NR activity. We also demonstrated that LeSPL-CNR inhibited the SlNR promoter activity in vivo and bound to SlNR promoter sequence that does not contain a known SBP-binding motif. In addition, expression of an IRON-REGULATED TRANSPORTER1, SlIRT1, was more abundant in Cnr roots than AC roots under Cd stress. LeSPL-CNR may thus provide a molecular mechanism linking Cd stress response to regulation of NR-dependent NO production, which then contributes to Cd uptake via SlIRT1 expression in tomato.
MAIN CONCLUSION: An SPL-type transcription factor, LeSPL-CNR, is negatively involved in NO production by modulating SlNR expression and nitrate reductase activity, which contributes to Cd tolerance. Cadmium (Cd) is a highly toxic pollutant. Identifying factors affecting Cd accumulation in plants is a prerequisite for minimizing dietary uptake of Cd from crops grown with contaminated soil. Here, we report the involvement of a SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE (SPL) transcription factor LeSPL-CNR in Cd tolerance in tomato (Solanum lycopersicum). In comparison with the wild-type Ailsa Craig (AC) plants, the Colourless non-ripening (Cnr) epimutant displayed increased Cd accumulation and enhanced sensitivity to Cd, which was in well accordance with the repression of LeSPL-CNR expression. Cd stress-induced NO production was inhibited by nitrate reductase (NR) inhibitor, but not NO synthase-like enzyme inhibitor. Expression of LeSPL-CNR was negatively correlated with SlNR expression and the NR activity. We also demonstrated that LeSPL-CNR inhibited the SlNR promoter activity in vivo and bound to SlNR promoter sequence that does not contain a known SBP-binding motif. In addition, expression of an IRON-REGULATED TRANSPORTER1, SlIRT1, was more abundant in Cnr roots than AC roots under Cd stress. LeSPL-CNR may thus provide a molecular mechanism linking Cd stress response to regulation of NR-dependent NO production, which then contributes to Cd uptake via SlIRT1 expression in tomato.
Entities:
Keywords:
Cadmium toxicity; Iron uptake; Solanum lycopersicum; Transcription factor
Authors: Ladislav Tamás; Jana Dudíková; Katarína Durceková; L'ubica Halusková; Jana Huttová; Igor Mistrík; Marta Ollé Journal: J Plant Physiol Date: 2007-12-26 Impact factor: 3.549
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