The response of Phalaenopsis amabilis seedling (in vitro and greenhouse) after Salicylic acid treatment to Dickeya dadantii infection

Abstract

Abstract Phalaenopsis amabilis is one of the popular orchid species having white flowers. However, P. amabilis is susceptible to soft-rot disease caused by Dickeya dadantii infection (a necrotrophic pathogen). This research aimed to induce P. amabilis resistance to D. dadantii using salicylic acid (SA). The SA treatment at 0 or 30 ppm was applied in the tissue culture medium of P. amabilis plantlets, and at 0, 15, 30, 45, 60, 75, or 90 ppm was used to four months old seedlings in the greenhouse. Leaves of either in vitro plantlets or seedlings were inoculated with D. dadanti by using the detached leaves inoculation method. Bacterial inoculation was carried out at 1, 2, or 3 days after SA treatment on in vitro plantlets and one day after on seedlings in the greenhouse. The results showed that SA treatment did not induce the resistance of in vitro plantlets., on the other hand, SA 45 ppm treatment slightly increased P. amabilis resistance to D. dadantii infection. Further studies are needed to confirm this finding and explore the SA role in P. amabilis resistance mechanism to necrotrophic pathogens.