Evaluation of anthurium cultivars for resistance to Xanthomonas axonopodis pv. dieffenbachiae, the causal agent of bacterial blight
Bacterial blight is a devastating disease of anthurium caused by Xanthomonas axonopodis pv. dieffenbachiae (Xad). Although modifications in cultural practices have reduced losses and outbreaks, anthurium blight continues to be a worldwide concern. Sources of resistance for breeding programs in addition to Anthurium antioquiense are needed because cultivar selection is often dictated by aesthetic properties not found in A. antioquiense hybrids. Genetically engineered plants with resistance are commercially unavailable. As anthuriums grow slowly and evaluation of large plants can take several years, microplants (approximately 4 weeks after deflasking) were evaluated in the current study. Leaves were inoculated with a bioluminescent strain of Xad and subsequently autophotographed to detect Xad colonization. Eleven cultivars were compared in repeated trials to the susceptible 'Marian Seefurth' and resistant 'Kalapana' controls. Incidence and severity data collected from autophotographs showed a range from highly susceptible to moderately resistant but no cultivar was immune. Complementary studies were undertaken using an intensified charged couple device (ICCD) camera to provide non-destructive measurements of Xad colonization. The ICCD system captured real-time bioluminescence and permitted the tracking of Xad colonization throughout the plant. Evidence for early systemic infection through only a few infection sites highlights the need to assess the entire plant. The new microplant rating system is a breeder's tool for selection of cultivars for subsequent greenhouse and field trials and eventually will enable growers to modify planting designs and cultural practices.
Ayin, C.M., Amore, T.D., Toves, P.J., de Silva, A.S. and Alvarez, A.M. 2017. Evaluation of anthurium cultivars for resistance to Xanthomonas axonopodis pv. dieffenbachiae, the causal agent of bacterial blight. Acta Hort. (ISHS) 1167:245-250
autophotography, bioluminescence, disease incidence, disease severity, ICCD camera, microplant evaluation