Parasitic plants of the family Broomrape, such as Striga, which are feared as "witch weeds", start infesting by recognizing the quinone compound of the host plant, stealing water and nutrients and significantly reducing the yield of grains.Until now, it was unclear how parasitic plants recognize quinone compounds, and whether non-parasitic plants can also recognize quinone compounds, but this time, a new receptor involved in the recognition of quinone compounds in plants has been discovered.A joint research team of RIKEN and Chubu University made a presentation.
The researchers first confirmed that administration of the quinone compound DMBQ to the non-parasitic plant Arabidopsis increases the intracellular calcium ion concentration.Therefore, using a marker of intracellular calcium concentration, we identified mutants that do not respond to DMBQ (cannot recognize quinone compounds) and performed whole-genome sequence analysis, and succeeded in identifying the causative gene CARD1. CARD1 encodes a receptor-like kinase and is thought to play an important role in the recognition of quinone compounds.
We also found that CARD1-dependent expression genes are involved in the response to wounds, immunity, and stress, and that CARD1 mutants have reduced resistance to pathogens.Since microorganisms are known to produce large amounts of quinone compounds, CARD1 may induce a protective response to pathogens by recognizing quinone compounds.
Furthermore, it was found that the intracellular calcium concentration of Phtheirospermum japonicum, which is the same as Striga, is also increased during DMBQ treatment, which plays an important role in the formation of the sucker (special organ for parasitism) of Phtheirospermum japonicum.When the CARD1 homologous gene of Phtheirospermum and Striga was introduced into the CARD1 mutant of Arabidopsis thaliana, the DMBQ recognition function could be complemented, indicating that the quinone compound is also recognized in parasitic plants.
It is expected that this result will contribute to the understanding of the parasitic mechanism of parasitic plants, the development of new control methods, the elucidation of the immune mechanism of plants, and the improvement of pathogenic resistance.
Paper information:[Nature] Quinone perception in plants via leucine-rich-repeat receptor-like kinases
