Genes contain the “instructions” that determine the structure and function of all living tissues.  Each gene or combination of genes, produce proteins that form tissues that carry out these specific functions.  Not all genes continuously produce their proteins. Promoters can enhance the production of certain proteins, and promoters can be told when they should promote protein production by regulator genes.  Regulator genes, in their most simplistic form, may be thought of as gene switches that can turn genes on and off, and in some cases, turn genes on and off by external stimuli. There are commercial products that can turn genes on, but not quite like the illustration shows.

SAR’s

When a pathogen attacks a plant, the plant reacts to survive.  Gene switches are turned on to produce proteins that in some way help the plant to defend itself against the attack.  In other words, the plant turns on a defense mechanism.  When a plant turns on its defense mechanism in every part of the plant, in response to a chemical or pathogen, it’s known as a Systemic Acquired Resistance by the plant or SAR.  There are several commercial chemical sprays that will turn on genes in a plant, producing a Systemic Acquired Resistance to disease.  One of these chemicals, is a product put out by Syngenta Crop Protection called Actigard. Actigard does not directly affect disease causing organisms, it only activates defense mechanisms in the plant, that help it resist attack by these organisms

ISR’s

When plant defense mechanisms are induced by a microorganism that does not cause disease, it is referred to an Induced Systemic Resistance or ISR.  Bayer Crop Science puts out an ISR seed treatment called Yield Shield. Yield Shield is a bacterial seed treatment (Bacillus pumilus GB34) that, again, does not directly attack disease causing organisms.  It turns on gene switches in the plant, which start the plants defense mechanisms, which help the plant resist attack. 

Now let your imagination go.

OK… We see that it is possible to turn on genes by application of chemicals or friendly bacteria.  Can we use chemicals or friendly bacteria to turn on other genes to help the plant?  How about the use of other external stimuli to turn on genes?  Is there a way to make genes turn on only at a certain temperature?, or maybe at a certain plant age?, or maybe only during times of drought?

Time will tell. 
Next time we’ll talk about “Pelleting Seed in a Rotary Coater…A New Trend”. 
Hope to see you then.