Title : Phosphatidic acid, a signal molecule in wheat seedlings under stress conditions and Trichoderma presence
Anomalies in environmental conditions activate in plants a series of processes that allow minimizing their negative impact. These factors, such as drought or dangerous pollutants may result in changing the profile of cytoplasmic membranes phospholipids and induce synthesis of the lipids signaling messenger, phosphatidic acid (PA). In this work, we investigated the effect of drought and/or synthetic auxin herbicide, 2,4-dichlorophenoxyacetic acid (2,4-D), on the phospholipid profile of wheat (Triticum aestivum L.) seedlings, with the special emphasis on the PA level. Moreover, because Trichoderma spp. is known to offer a beneficial relationship with plants, the phospholipid composition in wheat roots and shoots under stress conditions in T. harzianum presence was observed. Phospholipid differences between samples were analyzed using liquid chromatography/electrospray ionization–MS/MS. In the group of 4-day-old seedlings exposed to the herbicide the inhibition of growth was observed (in the shoots and roots). Concurrently, in seedlings inoculated with T. harzianum and herbicide the growth inhibition was partly alleviated. Overall, the PA level was higher in the roots than in the shoots. The presence of the fungus did not increase the PA level in the plants, also the herbicide did not induce PA accumulation. On the other hand, a strong, 4-fold increase in the level of the lipid messenger was found in samples exposed to the insufficient water content. The obtained results confirmed the important role of PA in plant stress signaling and beneficial relationship of T. harzianum with wheat. This study was supported by the National Science Centre in Krakow, Poland (Project No. 2015/19/B/NZ9/00167).