To achieve our goals, we combine genetics and biochemical approaches, and collaborate with chemists in our institute
Quinones are produced by all kingdoms, with plants as the major producer. Quinones have been long known to influence plant physiology, such as a black walnut-derived quinone can inhibit the growth of other plants growing nearby. Further, 2,6-dimethoxy-1,4-benzoquinone (DMBQ) - a type of quinone that is detected in a variety of plant species is able to initiate haustorium (a feeding organ) development in parasitic plants. It is important to note that non-parasitic plants, such as Arabidopsis, do not form haustorium upon quinone perception.
We have previously shown that plants can perceive quinones as signalling molecules through a plant-specific leucine-rich repeat receptor-like kinase (LRR-RLK) named CARD1 for Cannot Response to DMBQ (also called HPCA1). Interestingly, DMBQ induces defense-related responses and stomata closure in non-parasitic plants, in contrast to a root parasitic plant where quinones induce haustorium formation.
Do different plant species show different responses to different types of quinones? Do quinone signals have another role in plants? Are there other quinone receptor in plants? What are other components in the quinone signalling pathway and are they evolved? These are the questions that we are now attempting to answer.
Although a wide range of quinone compounds are documented in plants, quinone biosynthesis in plants remain largely elusive. This is especially true for secondary quinone metabolites. Nevertheless, plants may control what type of quinones are produced in a spatio-temporal pattern and thus use different quinone compounds for different roles.
In collaboration with other researchers, we will employ chemistry and genetics in an attempt to define biosynthetic pathways for secondary quinone metabolites and thus identify new quinone compounds from plants that play an important role in plant signalling and physiology.
In parallel with research on how quinones are produced in plants, we are also interested in where quinones are generated, and their dynamics in plant cells or tissues. Such information will further help to define the role of quinone in plants. Since the knowledge on plant-derived secondary quinones is scarce, it is important to design quinone probes that are broad enough to detect a wide range of quinones in plants, while maintaining some specificity such they will not react to other molecules produced in plants.
In this project, we will attempt to design genetic or chemical probes, that can specifically interact with specific quinones and determine quinone dynamics in plant cells. Together with information on how plants quinone biosynthesis, we will see how quinone signals are generated, propagated and perceived in plants.
Plants are constantly exposed to various chemicals and stimuli in their environment. While proteinaceous ligands and their cognate receptors have been extensively characterised in plants, less is known about how plants perceive non-proteinaceous ligands. Further, plant genomes contain many different types of receptors, many of which remain uncharacterised.
By employing genetic screens, using reporter systems, as well as in-house chemical library resources, we aim to elucidate plants sense different types of chemicals within the environment. Together with in-house chemists at the institute, we hope to create new chemical compounds that influence plant physiology and productivity.