Exogenous application of salicylic acid improves eradication of apple stem grooving virus and apple chlorotic leaf spot virus in apple by combining thermotherapy with shoot tip culture or cryotherapy

Abstract

Abstract The presence of viral diseases poses a significant challenge to the high-quality, efficient, and sustainable production of apples. Virus eradication and the use of virus-free plants is currently the most crucial method for preventing viral diseases. Among the viruses affecting apples, apple stem grooving virus (ASGV) and apple chlorotic leaf spot virus (ACLSV) present particular challenges in efficient eradication from apples. This study investigated the effects of exogenous salicylic acid (SA) treatment on efficient eradication of these viruses from apple ‘Yanfu 8’ after combining thermotherapy with shoot tip culture or cryotherapy. Results showed that the inclusion of 10 µM SA in thermotherapy significantly decreased the concentrations of ASGV and ACLSV by 73–85% in shoots as compared with that treated without SA. SA treatment also improved the shoot tips survival and regrowth after combining 2 or 4 weeks of thermotherapy followed by shoot tip culture or shoot tip cryotherapy, while maintaining the higher (75–100%) of virus eradication efficiencies. Therefore, the application of SA in combination with thermotherapy proves to be a promising approach for enhancing the efficiency of virus eradication in apple.