Current Research

My research interests are currently focused on molecular recognition events and signalling between the pollen and stigma in species belonging to the Brassicaceae (including Brassica oleracea and Arabidopsis thaliana).

Pollinations can be either compatible or incompatible and a molecular dialogue is established within minutes of the arrival of the pollen grain at the stigma surface that will lead either to acceptance or rejection of the pollen.

Brassica oleracea, in common with many flowering plant species, prevents self-fertilization by a mechanism termed self-incompatibility (SI). Simply, SI permits the recognition and rejection of 'self' pollen - an attribute that promotes genetic diversity and one that is held to have been crucial to the rapid adaptive radiation of flowering plants early in their evolutionary history. SI in Brassica is controlled by a single multiallelic locus, the S-locus. The female determinant is known to be a transmembrane receptor kinase, the SRK (S-receptor kinase), which is thought to be activated by binding the pollen-borne determinant of SI, SCR (for S cysteine-rich protein). Activation of SRK initiates a signalling cascade that ultimately leads to pollen rejection probably through denial of access to stigmatic water.

My research has established that SCR is but one member of a family of small cysteine-rich pollen coat proteins (the PCP-A class) that bind stigmatic proteins known to have roles in pollen-stigma interactions and recognition. These proteins tend to be gametophytically expressed (see figure) and are secreted from the pollen protoplast to ultimately end up on the surface of the grains. Studies are underway to further characterise this family of proteins and establish their functions during the pollination process.

Further, although the primary determinants of SI have been identified, gaining an understanding of the molecular basis of S-specific recognition and the precise mode of activation of the SI system is of particular interest in my lab.

Goals

To further our understanding of the molecular basis of pollen recognition and rejection both within and between species.