We have a series of projects that centre around a small regulatory microRNA called miR159 that confers endogenous gene silencing. MiR159 is ancient and highly conserved, being present in all land plants where it regulates the expression of a family of genes encoding GAMYB transcription factors. GAMYB promotes programmed cell death (PCD) in seeds and anthers, and although GAMYB is strongly and ubiquitously transcribed in vegetative tissues, its expression is fully silenced by miR159.
Recently we have shown that inhibition of miR159 via MIMIC technology in the model plant tobacco, results in the activation of GAMYB expression, which in turn activates a plethora of genes involved in plant defense pathways. These MIMIC tobacco plants were subsequently shown to be highly resistant to the plant pathogen, Phytophthora. This demonstrates in tobacco that the miR159-GAMYB pathway is a post-transcriptional regulatory mechanism controlling plant defense pathways.
We have projects that aims to address one or more of the following questions.
- Activation of GAMYB and the defense pathways results in a yield/growth penalty resulting in MIMIC tobacco plants that are dwarf. Can we manipulate this pathway, so to transiently activate this pathway, to result in disease resistance without the yield penalty?
- Biotechnological applications; can we engineer new synthetic alleles of the MIMIC so that miR159 is inhibited on pathogen attack? Can this result in increased disease resistance in plants?
- Conservation of the pathway; miR159 regulation of GAMYB is ancient, therefore how widely is this disease resistance pathway conserved?
Spectrum; how broad does this defense pathway confer resistance; bacteria, fungi, oomycetes, nematodes, insects?