Submitted to: International Congress on Molecular Plant-Microbe Interactions
Publication Type: Abstract Only
Publication Acceptance Date: 7/15/2005
Publication Date: 12/30/2005
Citation: Lartey, R.T., Kersey, S., Ghoshroy, S. 2005. A light and scanning electron microscopic study of progression of cercospora beticola infection in sugar beet and safflower. In: Book of Abstracts, 2005. XII International Congress on Molecular Plant-Microbe Interactions, December 14-19, 2005, Merida, Mexico. Abstract P4-10, Page 129. Interpretive Summary:
Technical Abstract: Sugar beet and subirrigated safflower are sometimes rotated in Sidney, MT region of Northern Great Plains (NGP). Cercospora beticola and C. carthami are known to infect sugar beet and safflower respectively. C. beticola is ubiquitous in sugar beet, but C. carthami has not been reported in NGP. Observations of unusual leaf spots on subirrigated safflower cv. Centennial in Sidney, MT led to investigation of safflower as an alternate host to C. beticola. We subsequently identified safflower as a host of C. beticola in a report that for the first time recognized cross infection of a host that had previously been identified as a host of another Cercospora species. This project describes a comparative microscopic study of spread of C. beticola infection in sugar beet and safflower. The two crops were manually infected with inoculum spores of two isolates of C. beticola (C2 and Sid 1). Gradual development of the pathogen on the leaf surface and disease symptoms were investigated with scanning electron microscope operated at a variable pressure mode. Some specimens were sputter coated with gold to obtain images with higher resolution. The lesions in both sugar beet and safflower showed a substantial amount of hyphal mass. The areas with no apparent lesions lacked mycelia, indicating a fairly restricted spread of hyphae. A number of stomatal apertures in lesion areas of both hosts plants clearly showed protruding hyphae, which may indicate presence of internalized hyphae after establishment of infection. Further investigations are in progress to study the ultrastructure of leaf cells in the lesion area to determine the extent of infection spread in various cellular compartments. In addition, assay of the symptoms by PCR, showed the presence of C. beticola in the lesions.