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The bulls-eye of the wrong target

We have become masterful at hitting the bull’s eye of the wrong target.

A colleague sent me a recent article1 describing the discovery of a master gene that regulates iron absorption in plants. You can read a journalist’s popularized version here.

Just so we are clear, iron absorption is not a genetics problem. This is a soil redox and microbial problem.

There is abundant iron in the earth’s crust and in our soils, around 4% or so. Most soil analysis results report excessive iron.

The iron that is in our soils, and that is measured on our soil analysis is often not physiologically active in plants because it is in the oxidized form that is unavailable for absorption. 

It is largely in the oxidized form because of how our soils have been mismanaged. We have shifted the microbial population and the general soil environment in the direction of excessive oxidation, and inadequate reduction. 

It is the function of beneficial microbial populations in the soil to convert iron and other elements from the oxidized to the reduced form and improve their plant availability. This only happens when we have a soil environment that can support the right biology and allow this transition to occur. 

When you change soil biology and redox status, crops will have an abundant supply of iron. And manganese. And cobalt. And copper.

Changing plant genetics to improve absorption of the wrong form of an abundant mineral completely misses the obvious.

Kim, S. A., LaCroix, I. S., Gerber, S. A. & Guerinot, M. L. The iron deficiency response in Arabidopsis thaliana requires the phosphorylated transcription factor URI. Proc. Natl. Acad. Sci. U. S. A. 116, 24933–24942 (2019).