PS Seminar Series - Tales from the transcriptome: Characterising FERONIA function through comparative gene expression analysis

Abstract -  FERONIA (FER) is a plant receptor kinase of many functions, binding to pectin in the cell wall and mediating an astoundingly broad range of plant activities. These include fertilisation, hormone signalling, regulating cell shape, and protection from multiple environmental stresses. This is reflected in fer knockout mutants which exhibit wide-ranging defects. FER also acts as the receptor for a range of signalling peptides known as Rapid Alkalinisation Factors (RALFs) which modify FER function. FER is targeted extensively during pathogen infection with multiple pathogen-secreted proteins, including pathogen-encoded RALF peptides which bind to FER to facilitate infection.

Despite involvement of FER in multiple processes, little links known FER functions with the many disparate phenotypes of fer knockout mutants. Similarly, the relationship between RALF peptide signalling and the absence of FER remains to be adequately explored. To address this, I have used a non-targeted approach to characterise the transcriptional profile of fer knockout mutants through comparative transcriptomic analysis. I have supplemented this analysis where necessary with laboratory experiments. My analysis reveals a that the transcriptional changes induced by FER’s absence vary greatly between root and aerial tissues, partially aligning with the changes induced by RALF peptide application. I also reveal a role for FER in regulating the sugar-linked expression of salicylic acid (SA) responsive genes, indole-based secondary metabolism, and maintenance of cuticular integrity.

Together, these results allow the assembly of a more unified model of the defects present in fer knockout mutants and open further avenues for molecular characterisation of this functionally complex receptor.

Biography - Alex is a PhD candidate in the Rathjen lab, Division of Plant Sciences, RSB, ANU. Prior to his PhD, he completed a Bachelor of Science (Honours) at ANU.

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