Overexpression of annexin gene in rice (Oryza sativa L.) for salinity and water stress

The aim of the study is to develop transgenic rice with annexin genes (AnnBj2) to determine its salinity and water stress tolerance through Agrobacterium-mediated genetic transformation. The transgenic somatic embryos were developed on Murashige and Skoog medium fortified with 0.5 mg L−1 kinetin and 3.0 mg L−1 2,4-D. About 80% of the transformed somatic embryos germinated and was successfully established in the transgenic greenhouse. The transformed plantlets (T0 and T1 generation) were identified through PCR using NPT-II and AnnBj2 gene–specific primers as well as positive uidA reporter gene expression. Compared with non-transformed plants, the transgenic rice plants overexpressing AnnBj2 gene exhibited salt tolerance at the seedling stage. Seeds generated at T0 and T1 generations were further studied to determine their salinity tolerance through nutrient culture and pot culture experiments for water stress. When compared with the non-transgenic control, transgenic seeds (T0 and T1) had increased germination on a nutrient medium having 200 mM NaCl. The data showed that the shoot and root lengths were longer at 200 mM NaCl when compared with those of the non-transformed plants. Further, the biochemical assessment (photosynthetic pigment analysis, protein, proline content, and oxidative enzyme activity) was performed between transformed (T0 and T1) and non-transformed plantlets under stress. It was noted that the transformed plantlets were higher in chlorophyll and proline content as well as oxidative enzyme activity as compared with the non-transformed plants.