DISTEBA, Department of Biological and Environmental Sciences and Technologies, University of Salento, via Prov. le Lecce-Monteroni, 73100, Lecce, Italy.
Plant Cell Rep. 2017 Sep;36(9):1361-1373. doi: 10.1007/s00299-017-2159-3. Epub 2017 Jun 2.
Triticum durum Glutathione S-transferase Z1 is specifically responsive to glyphosate. Its expression influences the receptor-mediated vacuolar sorting mechanisms involved in tolerance mechanisms. A zeta subfamily glutathione S-transferase gene from Triticum durum (cv Cappelli) (TdGSTZ1) was characterized as part of a complex detoxification mechanism. The effect of different abiotic stresses on TdGSTZ1 revealed that the gene is unexpectedly responsive to glyphosate (GLY) herbicide despite it should not be part of tolerance mechanisms. Its role in the non-target-site mechanism of GLY resistance was then investigated. To analyze the GLY and the TdGSTZ1 overexpression effects on vacuolar sorting mechanisms, we performed transient transformation experiments in Nicotiana tabacum protoplasts using two vacuolar markers, AleuGFPgl133 and GFPgl133Chi, labeling the Sar1 dependent or independent sorting, respectively. We observed that the adaptive reaction of tobacco protoplasts vacuolar system to the treatment with GLY could be partially mimicked by the overexpression of TdGSTZ1 gene. To confirm the influence of GLY on the two vacuolar markers accumulation and the potential involvement of the secretion pathway activity in detoxification events, Arabidopsis thaliana transgenic plants overexpressing the non-glycosylated versions of the two markers were analyzed. The results suggested that GLY treatment specifically altered different vacuolar sorting characteristics, suggesting an involvement of the receptor-mediated AleuGFP sorting mechanism in GLY resistance. Finally, the expression analysis of selected genes confirmed that the non-target-site GLY resistance mechanisms are related to vacuolar sorting.
硬粒小麦谷胱甘肽 S-转移酶 Z1 对草甘膦具有特异性响应。其表达影响参与耐受机制的受体介导的液泡分拣机制。来自硬粒小麦（Cappelli 品种）的 ζ 亚家族谷胱甘肽 S-转移酶基因（TdGSTZ1）被表征为复杂解毒机制的一部分。不同非生物胁迫对 TdGSTZ1 的影响表明，该基因出人意料地对草甘膦（GLY）除草剂有反应，尽管它不应该是耐受机制的一部分。然后研究了它在 GLY 抗性的非靶标位点机制中的作用。为了分析 GLY 和 TdGSTZ1 过表达对液泡分拣机制的影响，我们使用两种液泡标记物，AleuGFPgl133 和 GFPgl133Chi，在烟草原生质体中进行了瞬时转化实验，分别标记 Sar1 依赖或独立的分拣。我们观察到，烟草原生质体液泡系统对 GLY 处理的适应性反应可以部分模拟 TdGSTZ1 基因的过表达。为了确认 GLY 对两种液泡标记物积累的影响以及分泌途径活性在解毒事件中的潜在参与，分析了过表达两种标记物的非糖基化版本的拟南芥转基因植物。结果表明，GLY 处理特异性改变了不同的液泡分拣特征，表明受体介导的 AleuGFP 分拣机制参与了 GLY 抗性。最后，对选定基因的表达分析证实，非靶标位点 GLY 抗性机制与液泡分拣有关。
