Tuesday, February 8, 2011
Timing of Immune Response to Defend Against Disease
I thought this article from the New York Times is very relevant to what were talking about in class! The plant Arabidopsis is really intersting, it has developed the ability to express genes at specific times to make it resistant to an infectious pathogen.
Specifically, twenty-two genes were discovered in Arabidopsis that are all connected to the plant’s ability to resist infection. These genes are unique in that they are expressed only from the evening onward, peaking at dawn.
This timing corresponds with the formation of spores in a funguslike pathogen that attacks the plant and results in a condition known as downy mildew disease. The disease weakens the plant and forms an unsavory coating of fuzzy mildew.
A surprising discovery published in the Nature journal, found that these new defense genes are under circadian control by the regulator CIRCADIAN CLOCK-ASSOCIATED 1 (CCA1), allowing plants to ‘anticipate’ infection at dawn when the pathogen normally disperses the spores. Arabidopsis can then time its immune response according to the perception of different pathogenic signals upon infection. This plant then uses programmed cell death as its main contributor to resistance.
I think that the control of defensive genes by a circadian clock regulator is an amazing adaptation this plant has made to avoid being susceptible to dawn spore attacks, just like the grass in class on the copper mines flowering early to gain an advantage to remain resistant to the toxins in the soil. Hope you think this is interesting too!
Posted by Ella at 9:47 AM