Location: Molecular Plant Pathology LaboratoryTitle: Characterization of a Beta vulgaris PGIP defense gene promoter in transgenic plants Author
Submitted to: Annual Beet Sugar Development Foundation Research Report
Publication Type: Research Technical Update
Publication Acceptance Date: 4/28/2015
Publication Date: 6/5/2015
Citation: Smigocki, A.C., Li, H., Padmanaban, S., Mongeon, J.E. 2015. Characterization of a Beta vulgaris PGIP defense gene promoter in transgenic plants. Annual Beet Sugar Development Foundation Research Report. http://www.bsdf-assbt.org/assbt/assbt.htm. Interpretive Summary: Gene switches that are specifically activated by pathogen invasion or insect pest attack are needed for effective expression of resistance genes that have the potential to protect plants from diseases and insect pests. Present study provides newly gained knowledge about a sugar beet root gene (BvPGIP) that is specifically induced upon insect attack. The regulatory switch that activates the expression of this gene was isolated. The BvPGIP switch provides for gene expression in the leaves but highest levels of expression are observed in the roots. In addition, root expression is enhanced by mechanical wounding of the roots, a response not observed in the leaves. Based on our findings, we propose that this gene switch may be useful for directing the expression of disease and pest resistance genes to roots as a strategy for improving plant disease resistance. This information will be used by scientists to develop improved crops capable of resisting pests and diseases thus improving the safety of consumable foods by reducing the usage of pesticides.
Technical Abstract: Polygalacturonase-inhibiting protein (BvPGIP) genes were cloned from a sugar beet breeding line F1016 with increased tolerance to the sugar beet root maggot. Polygalacturonase-inhibiting proteins are cell wall leucine-rich repeat (LRR) proteins with crucial roles in development, pathogen defense and recognition of beneficial microbes in plants. PGIPs inhibit pathogen and pest polygalacturonases (PGs) during the infection process. Highest expression of the BvPGIP genes was shown to be associated with F1016 roots, followed by leaves, petioles and hypocotyls, suggesting that the genes are developmentally regulated. Expression of the GUS reporter gene from the BvPGIP gene promoter in transgenic BvPGIP Nicotiana benthamiana plants was observed in leaf vasculature. Mechanical wounding of the leaves did not induce GUS gene expression at the wound sites. Further studies to determine BvPGIP expression and wound response in N. benthamiana roots are in progress. Characterization of BvPGIP gene expression and developmental regulation will advance the development of novel approaches for more effective disease and pest control in sugar beet.