Virus elimination from asparagus seedlings by ascorbic acid and slow-freezing treatments
Asparagus virus 1 (AV-1) and Asparagus virus 2 (AV-2) are major pathogenic viruses that cause the reduction of vigor and productivity of asparagus. It is not easy to prepare the virus-free asparagus through in vitro culture for field production, thus we here tried to establish a new approach for virus elimination from asparagus by using ascorbic acid (AsA) treatment and slow-freezing cryotherapy. AV-1 and AV-2 double infection in the asparagus spears were first confirmed by RT-PCR and then the shoot tips were excised from spears and cultured in vitro. Viral infections in asparagus seedlings developed from the shoot tips were further examined and the doubly-infected seedlings were maintained and used for subsequent experiments. For ascorbic acid treatment experiments, tissue fragments containing a lateral bud were excised from cultured seedlings and put on the medium supplemented with various concentrations of AsA. For slow-freezing treatment experiments, tissue fragments were excised at various sizes and then cooled to -40°C at -0.5°C min‑1. In the results, viral elimination was detected in seedlings by either ascorbic acid or slow-freezing treatments. In ascorbic acid treatments, there were differences in elimination rate among asparagus cultivars, and in slow-freezing treatments the viral elimination rate did not depend on the excised tissue size.
Matsuo, N., Shimura, H. and Suzuki, T. (2020). Virus elimination from asparagus seedlings by ascorbic acid and slow-freezing treatments. Acta Hortic. 1301, 173-178
Asparagus officinalis, virus-free, shoot-tip culture, ascorbic acid, slow-freezing