Characterizing morphological and genetic variation of soil fungal pathogen Rhizoctonia solani

Conference Year

January 2020

Abstract

Rhizoctonia solani is a soilborne fungal pathogen that targets crops such as lettuce and potato. Between 30-50% of a lettuce crop is lost to R. solani in Vermont. There is limited information regarding specific strains (anastomosis groups (AG)) of R. solani in Vermont. Obtaining AG groups is essential to combat this disease with effective control strategies. In this study, 31 Vermont vegetable farms were sampled to determine the cause of lettuce and potato rot. R. solani was isolated from diseased tissue samples and by baiting with radishes. Isolates were obtained from 16 of the 31 farms. The hyphal branching was examined under a microscope to make an initial determination of R. solani, and a catalog was created with photographs of colony and branching patterns for each isolate. Among the Rhizoctonia colonies, variations such as differences in hyphal cell shape were seen; some were more beaded and others were more linear. Sclerotia formation and colony color also differed among isolates. A representative sample size of 20 isolates was chosen for a polymerase chain reaction (PCR) to determine specific AG groups. Isolates representing three large Vermont lettuce growers serve as a reference to develop selective media as diagnostic tools.

Primary Faculty Mentor Name

Deborah Neher

Secondary Mentor Name

Thomas Weicht

Graduate Student Mentors

Tucker Andrews

Faculty/Staff Collaborators

Dr. Deborah Neher (Faculty Advisor), Thomas Weicht (Senior Technician), Tucker Andrews (Graduate Student)

Status

Undergraduate

Student College

Rubenstein School of Environmental and Natural Resources

Program/Major

Wildlife and Fisheries Biology

Primary Research Category

Biological Sciences

Abstract only.

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Characterizing morphological and genetic variation of soil fungal pathogen Rhizoctonia solani

Rhizoctonia solani is a soilborne fungal pathogen that targets crops such as lettuce and potato. Between 30-50% of a lettuce crop is lost to R. solani in Vermont. There is limited information regarding specific strains (anastomosis groups (AG)) of R. solani in Vermont. Obtaining AG groups is essential to combat this disease with effective control strategies. In this study, 31 Vermont vegetable farms were sampled to determine the cause of lettuce and potato rot. R. solani was isolated from diseased tissue samples and by baiting with radishes. Isolates were obtained from 16 of the 31 farms. The hyphal branching was examined under a microscope to make an initial determination of R. solani, and a catalog was created with photographs of colony and branching patterns for each isolate. Among the Rhizoctonia colonies, variations such as differences in hyphal cell shape were seen; some were more beaded and others were more linear. Sclerotia formation and colony color also differed among isolates. A representative sample size of 20 isolates was chosen for a polymerase chain reaction (PCR) to determine specific AG groups. Isolates representing three large Vermont lettuce growers serve as a reference to develop selective media as diagnostic tools.