Functional role of peroxidase gene in the resistance of the cut gerbera flower (Gerbera jamesonii) to stem bending disorder

Peroxidase is one of the most important genes in the lignin biosynthesis pathway. Polymerization of the phenolic derivatives into lignin, a connection between cell wall polymers such as monolignules, consequently, cell wall strength are the main functions of this enzyme. Accordingly, endogenous POD gene was isolated and cloned into gateway expression vector (PK7WG2) containing CAMV 35S promoter. Agrobacterium-mediated transformation was performed to introduce the construct into gerbera 'Panorama' cultivar. Following regeneration, putative transgenic plantlets were transferred to a soilless greenhouse. Molecular analysis of second-generation of transgenic plants by real-time PCR confirmed the presence of both internal and transgene in transgenic plants. In compared to wild-type, the POD enzyme activity was increased significantly in transgenic plants. Based on the results, transgenic plants showed higher enzyme activity and as a consequence less stem bending disorder than wild-type with lower enzyme activity and higher stem bending degree. Also, flower quality indices such as vase life and cell membrane stability in transgenic plants increased significantly compared with control. Transfer of transgen POD, in addition to improving the qualitative parameters of flower and increasing the water uptake by the flowering stem, significantly reduced the stem bending disorder of gerbera cut flower.