Departamento de Biologia Aplicada à Agropecuária, Universidade Estadual Paulista "Júlio de Mesquita Filho"-UNESP, 14884-900 Jaboticabal, SP, Brazil.
Plant Physiol Biochem. 2012 Jul;56:79-96. doi: 10.1016/j.plaphy.2012.04.009. Epub 2012 Apr 25.
In order to further address the modulation of signaling pathways of stress responses and their relation to hormones, we used the ethylene-insensitive Never ripe (Nr) and the auxin-insensitive diageotropica (dgt) tomato mutants. The two mutants and the control Micro-Tom (MT) cultivar were grown over a 40-day period in the presence of Cd (0.2 mM CdCl₂ and 1 mM CdCl₂). Lipid peroxidation, leaf chlorophyll, proline content, Cd content and antioxidant enzyme activities in roots, leaves and fruits were determined. The overall results indicated that the MT genotype had the most pronounced Cd damage effects while Nr and dgt genotypes might withstand or avoid stress imposed by Cd. This fact may be attributed, at least in part, to the fact that the known auxin-stimulated ethylene production is comprised in dgt plants. Conversely, the Nr genotype was more affected by the Cd imposed stress than dgt, which may be explained by the fact that Nr retains a partial sensitivity to ethylene. These results add further information that should help unraveling the relative importance of ethylene in regulating the cell responses to stressful conditions.
为了进一步探讨胁迫反应信号通路的调节及其与激素的关系，我们使用乙烯不敏感的 Never ripe（Nr）和生长素不敏感的 diageotropica（dgt）番茄突变体。将两个突变体和对照品种 Micro-Tom（MT）在含有 Cd（0.2 mM CdCl₂和 1 mM CdCl₂）的条件下生长 40 天。测定根、叶和果实中的脂质过氧化、叶片叶绿素、脯氨酸含量、Cd 含量和抗氧化酶活性。总的结果表明，MT 基因型对 Cd 损伤的影响最为明显，而 Nr 和 dgt 基因型可能耐受或避免 Cd 施加的胁迫。这一事实可能至少部分归因于 dgt 植物中已知的生长素刺激乙烯产生。相反，Nr 基因型比 dgt 更受 Cd 胁迫的影响，这可以用 Nr 对乙烯仍有部分敏感性来解释。这些结果提供了更多的信息，有助于阐明乙烯在调节细胞对胁迫条件的反应中的相对重要性。
