Transgenically expressed rice germin-like protein1 in tobacco causes hyper-accumulation of H2O2 and reinforcement of the cell wall components

Our recent report documented that the rice germin-like protein1 (OsGLP1), being a cell wall-associated protein involves in disease resistance in rice and possesses superoxide dismutase (SOD) activity as recognized by heterologous expression in tobacco. In the present study, the transgenic tobacco plants were analyzed further to decipher the detailed physiological and biochemical functions of the OsGLP1 and its associated SOD activity. The transgenic tobacco lines expressing SOD-active OsGLP1 showed tolerance against biotic and abiotic stresses mitigated by hyper-accumulating H2O2 upon infection by fungal pathogen (Fusarium solani) and treatment to chemical oxidizing agent (ammonium persulfate), respectively. Histological staining revealed enhanced cross-linking of the cell wall components in the stem tissues of the transgenic plants. Fourier transform infrared spectroscopy (FTIR) analysis of the biopolymer from the stem tissues of the transgenic and untransformed plants revealed differential banding pattern of the spectra corresponding to various functional groups. Our findings demonstrate that the OsGLP1 with its inherent SOD activity is responsible for hyper-accumulation of H2O2 and reinforcement of the cell wall components.

Research highlights
► Detailed physiological and biochemical functions of the rice germin-like protein1 (OsGLP1) have been established through heterologous expression in tobacco.
► The OsGLP1-espressing transgenic tobacco plants are tolerant against biotic and abiotic stresses.
► The antioxidative defense response is mitigated by hyper-accumulating H2O2 and enhanced cross-linking of the cell wall components including lignin.
► FTIR spectroscopy revealed changes in the chemical bonding among the biopolymers between the untransformed and transgenic stems of tobacco.
► The OsGLP1 gene has potential utility in developing transgenic crop plants tolerant against biotic and abiotic stresses.