Malectin domain proteins in plant reproduction

Organisms use environmental signals to determine how best to grow and develop. Receptors on the cell surface detect many diverse signals to monitor the biotic and abiotic environment surrounding the plant cell. Kinases are a major class of receptor proteins with hundreds of receptor kinases in plants. They are vitally important for agriculture and plant breeders because they recognise hormones, microbes, carbohydrates and other signals that are associated with plant development and defence.

One sub-class of receptor kinases are defined by the presence of an extracellular malectin domain, which has been linked to cell wall integrity monitoring and peptide binding. The family of malectin domain receptor kinases is greatly expanded in higher plants. Given the widespread occurrence of malectin domain receptor kinases, it is important to understand how they function in plant development and environmental responses. 

Our recent research has identified two malectin domain receptor kinases, HERK1 and ANJ, that act redundantly in the ovule during pollen tube reception. In the absence of HERK1 and ANJ, most pollen tubes fails to burst to release the sperm cells so fertilisation is impaired (see photo below).  Together with a related receptor kinase, FERONIA, HERK1 and ANJ act at the synergid cells to facilitate pollen tube reception. We are continuing to investigate the roles of HERK1 and ANJ in fertilisation through a BBSRC funded project (2022-2025). 

Link to our recent publication on the role of two malectin domain receptor kinases in fertilisation.

Link to our review on malectin domain receptor kinases.

Although the malectin domain is found mostly in conjunction with a kinase domain in plants (where it would be extracellular), this domain can also be found linked to a kinesin domain (a motor domain that moves around the cytoskeleton). We are studying the roles of the malectin domain kinesins in plant development and cell division. One of the two malectin domain kinesins in Arabidopsis is important for pollen and seed development. In the cell, it is often localised to the nucleus (see photo below), but has a dynamic localisation pattern during cell division. We have recently completed a Leverhulme Trust Research Programme Grant to study the function of this kinesin in cell division and plant development. If we can identify what malectin domain kinesins do during in cell division, this knowledge can potentially be used to target herbicides to plant-specific targets such as these malectin domain kinesins.

Link to our recent publication on the function of a malectin domain kinesin in plant development.

Projects in the lab have recently focussed on:

• Signalling between the ovule and pollen tube during reproduction (Dr Jen Sloan)

• Cell wall dynamics during plant reproduction (Dr Alice Baillie)

• Roles of malectin domain kinesins in cell division and embryogenesis (Dr Ellen Allwood)