Is the PLC pathway involved in the response to phenol treatment in tobacco hairy roots?

Abstract

Phospholipids and phospholipases play important roles in several cellular processes and responses to adverse growth conditions. However, the mechanism of action of phosphatidylinositol-specific phospholipase C (PI-PLC), and its resulting minor lipid function in response to pollutant-induced stress, remains to be elucidated. In this work, we studied the effects of phenol treatment on the PLC pathway, using two lines of hairy root cultures (HRs) from Nicotiana tabacum as plant model systems: wild-type (WT) and double-transgenic (DT) HRs. We quantified several product formations such as PIP, PIP 2 , DGPP, and PA, which are mainly synthesized by specific lipid kinases belonging to the PLC pathway. In both HRs, phenol treatment significantly increased the formation of these compounds in a differential manner. In WT HRs, PA formation was twofold higher than in control. PIP 2 and PIP levels were about onefold higher than those of the controls while DGPP levels increased by 50%. In DT HRs, PIP levels were onefold higher than those of the controls while PIP 2 , DGPP, and PA levels increased by 120%. Phenol treatment also upregulated the PLC4 gene expression mainly in the first hours of exposure in both HRs, while the DGK1 gene expression was only upregulated in WT HRs after 24 h of treatment. These results show an active participation of the PLC pathway under phenol treatment suggesting that this signal pathway could be important in plant cell responses to phenol-induced stress.