Nitric oxide is associated with long-term Zn tolerance in Solanum nigrum
| 作者： |
Jin Xu,Hengxia Yin,Yulong Li,and Xiaojing Liu |
| 刊物名称： |
Plant Physiol |
| DOI： |
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| 发表年度： |
2010-09-21 |
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| 摘要： |
Nitric oxide (NO) has been identified as a signal molecule thatinterplays with reactive oxygen species (ROS) in response toheavy metal stresses. Roles of NO in regulating cadmium (Cd)toxicity and iron (Fe) deficiency have been proposed; however,the function of NO in zinc (Zn) tolerance in plants remainsunclear. Here we investigated NO accumulation and its role inplants Zn tolerance. Zn-induced NO production promoted an increasein ROS accumulation in Solanum nigrum roots by modulating theexpression and activity of antioxidative enzymes. Subsequently,programmed cell death (PCD) was observed in primary root tips.Inhibiting NO accumulation by 2-phenyl-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxyde (PTIO, a specific NO scavenger) or NG-nitro-L-Arg-methylester (L-NAME, a NO synthase (NOS) inhibitor) prevented theincrease of superoxide radical (O2.-) and hydrogen peroxide(H2O2) as well as the subsequent cell death in the root tips,supporting the role of NO in Zn-induced PCD in the root tips.Zn-induced NO production affected the length of primary roots,the number of lateral roots and root hair growth and therebymodulated root system architecture and activity. Investigationof metal contents in Zn-treated roots suggests that NO is requiredfor metal (especially Fe) uptake and homeostasis in plants exposedto excess Zn. Taken together, our results indicate that NO productionand the subsequent PCD in root tips exposed to excess Zn arefavorable for S. nigrum seedlings response to long-term Zn toxicityby modulating root system architecture and subsequent adaptationto Zn stress. |
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