Response of sugarcane to increasing concentrations of copper and cadmium and expression of metallothionein genes
Response of sugarcane to increasing concentrations of copper and cadmium and expression of metallothionein genes
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DOI：
10.1016/j.jplph.2006.09.007
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发表时间：
2007-11-01
影响因子：
4.3
通讯作者：
Figueira, Antonio
中科院分区：
文献类型：
--
作者：
Sereno, Maria Lorena;Almeida, Raul S.;Figueira, Antonio
甘蔗（Sugarcane）由于其出色的生物量生产，提供了成为植物修复物种的潜力，但其潜在的金属积累和耐受性尚未得到充分表征。甘蔗试管苗能耐受100 μ M的铜，在33天内鲜重无明显下降，地上部干重积累45 mg·kg ~（-1）。较高水平的铜溶液（250和500亩M）是致命的。甘蔗表现出耐受500亩M镉没有中毒症状，积累451毫克镉kg（-1）后33天的地上部干重，表明其作为镉植物修复剂的潜力。用金属硫蛋白（MT）Ⅰ型探针进行DNA印迹分析，检测到8个片段，MT Ⅱ型显示白色10个，MT Ⅲ型显示8个。考虑到甘蔗品种的种间起源，甘蔗中每种类型的MT基因的数量可能与在水稻中鉴定的基因相似。MT I型基因表现出最高水平的组成型表达，主要在根中，其次是MT II型，证实了基于大规模表达序列标签测序所描述的表达模式。MT II型和III型基因在地上部中表达较多，MT I型基因在地上部中也有重要表达。增加铜浓度在调制MT基因的表达几乎没有影响，而一个明显的轻微调制的一些MT基因可以检测到镉处理。然而，水平。的响应是太小，不能解释甘蔗组织中的耐受性和/或积累的镉。因此，虽然MT可能参与了对高水平镉的氧化反应，但甘蔗对镉的耐受性和积累可能来自其他机制。甘蔗可以被认为是一个潜在的候选人进行测试镉植物修复。(C)2006年Elsevier GmbH。All rights reserved.
Sugarcane (Saccharum spp.) offers the potential to be a phytoremediator species due to its outstanding biomass production, but its prospective metal accumulation and tolerance have not been fully characterized. Sugarcane plantlets were able to tolerate up to 100 mu M of copper in nutrient solution for 33 days, with no significant reduction in fresh weight, while accumulating 45mg Cu kg(-1) shoot dry weight. Higher levels of copper in solution (250 and 500 mu M) were lethal. Sugarcane displayed tolerance to 500 mu M Cd without symptoms of toxicity, accumulating 451 mg Cd kg(-1) shoot dry weight after 33 days, indicating its potential as Cd phytoremediator. DNA get blot analyses detected 8 fragments using a metallothionein (MT) Type I probe, white 10 were revealed for the MT Type II and 8 for MT Type Ill. The number of genes for each type of MT in sugarcane might be similar to the ones identified in rice considering the interspecific origin of sugarcane cultivars. MT Type I gene appeared to present the highest level of constitutive expression, mainly in roots, followed by MT Type II, corroborating the expression pattern described based on large-scale expressed sequence tags sequencing. MT Type II and III genes were more expressed in shoots, where MT I was also importantly expressed. Increasing Cu concentration had little or no effect in modulating MT genes expression, while an apparent minor modulation of some of the MT genes could be detected in Cd treatments. However, the level. of response was too small to explain the tolerance and/or accumulation of Cd in sugarcane tissues. Thus, cadmium tolerance and accumulation in sugarcane might derive from other mechanisms, although MT may be involved in oxidative responses to high levels of Cd. Sugarcane can be considered a potential candidate to be tested in Cd phytoremediation. (C) 2006 Elsevier GmbH. All rights reserved.