2018 ASHS Annual Conference

Newly deflasked anthurium tissue culture plantlets are susceptible to infection by bacterial blight, resulting in mortality and economic losses for growers. Bacterial blight of anthurium is caused by the pathogen Xanthomonas axonopodis pv. dieffenbachiae (Xad). Silicates have been reported to increase plant resistance to disease. Anthurium andraeanum Hort. ‘Marian Seefurth’, is susceptible to bacterial blight and was selected to assess the effects of silicate amendments in reducing bacterial blight infection in newly deflasked microplants. Single nodes of ‘Marian Seefurth’ were cultured in liquid medium containing 3/8 strength Murashige and Skoog (MS), 2% sucrose and 0.2 mg/L benzyl adenine supplemented with either 1 mg/L sodium silicate or potassium silicate. After one month in liquid culture, the nodes with developing shoots were transferred to ½ strength MS containing 2% sucrose, 15% coconut water, 2% gellan gum and amended with 1 mg/L of either sodium silicate or potassium silicate. Control media did not contain any silicates. After 20 weeks on semi-solid medium, microplants were deflasked and grown in individual pots. Microplants were inoculated with a bioluminescent strain of Xad. Leaves and stems were detached from the microplants to assess disease incidence and severity 4 weeks post-inoculation. Disease incidence, as measured by the percentage of leaves infected per plant, was similar for the control and silicate treatments. However, disease severity, as measured by the leaf and stem areas colonized by Xad, was less in the silicate treatments. Silicate amendments appear promising as a means to increase microplant survival by reducing the severity of bacterial blight infection. Future experiments will evaluate reducing systemic infection of bacterial blight in microplants by extending the exposure to silicate amendments.