Discipline: Ecology Environmental and Earth Sciences
Subcategory: Plant Research
Shaveen McKen - Morgan State University
Co-Author(s): Sara Klee, Pennsylvania State University, University Park, PA; Judy Sinn, Pennsylvania State University, University Park, PA; Viji Sitther, Morgan State University, Baltimore, MD; Timothy McNellis, Pennsylvania State University, University Park, PA
Erwinia tracheiphila is one of the most destructive pathogens of cucurbits that causes bacterial wilt. Vectors such as the striped (Acalymma vittatum F.) and spotted (Diabrotica undecimpunctata howardi B.) cucumber beetles transmit E. tracheiphila through their mouthparts and residual frass, when the bacteria enter a wound present on the cucurbit plant. The objective of this study was to explore the virulence genetics of E. tracheiphila. An E. tracheiphila Tn5 transposon mutant library was created and screened for mutants that are non- pathogenic on ‘Ambrosia’ melon seedlings. About 2,000 selected mutants were inoculated on ‘Ambrosia’ melons at the cotyledon stage, as the first true leaves began to emerge. Wilt symptoms were observed over the course of ten days. Our results revealed that several mutants were not capable of causing wilt or very limited wilt. DNA flanking the Tn5 transposon insertion sites in mutants that were defective in virulence was isolated and sequenced to determine the genes that were disrupted. Potential functions of some of these mutated genes as related to the plant disease process were explored. Results of our study indicate that purine and exopolysaccharide biosynthesis are necessary for E. tracheiphila to cause disease on melons. This study has applied molecular genetic tools to the understanding of E. tracheiphila virulence, which is an area that is mostly unexplored. These results pave the way for additional studies of E. tracheiphila virulence genetics, including avirulent gene functions, which could be useful to develop plants resistant to bacterial wilt caused by this devastating pathogen.
Funder Acknowledgement(s): This work was supported by a grant from the USDA NIFA (Award # 2016-67032-25007) Research and Extension Experiences for Undergraduates (REEU) Program at Pennsylvania State University, University Park, PA
Faculty Advisor: Timothy McNellis, firstname.lastname@example.org
Role: All of the research