Optimization of storage temperature for the pollen viability of transgenic plants that express the anti-breast cancer monoclonal antibody mAb BR55

Abstract

Pollen germination viability is an essential factor in the production of seeds from pollination and fertilization. In this study, we optimized storage temperature conditions to increase the viability of pollen germination and pollen germ tube growth in transgenic plants that express the anti-breast cancer monoclonal antibody mAb BR55. The pollen of the transgenic plant BR55 was stored at five different temperatures: room temperature (RT), 4°C, -20°C, -70°C, or -196°C for 10 weeks. The in vitro pollen germination rate and pollen tube growth were observed at 10 weeks. The pollen was then germinated in vitro in sucrose buffer, either alone, or supplemented with 20 μg/mLboric acid. In general, both pollen germination rate and pollen tube growth increased with boric acid supplementation, compared to the control. The pollen germination rate and the pollen germ tube length were the greatest in pollen stored at -20°C (p < 0.01). The transgenic plant carrying the anti-colorectal cancer mAb CO17-1A HC and LC genes were pollinated using pollen (mAb BR55 transgenic plant) stored at -20°C, generating F1 seedlings carrying both mAb CO17-1A and mAb BR55 HC and LC genes. These results indicate that -20°C is the optimal temperature for pollen storage and ensures the pollen germination viability of transgenic tobacco plants that express therapeutic anti-cancer mAbs.