KIMBALL – Stories about agricultural runoff killing the Gulf of Mexico are all the rage in the major media these days. As usual, major media journalists play fast and loose with the truth, overstating and oversimplifying reality in order to sensationalize a story and set up a good versus evil paradigm.
One fact which is always missing from such stories is that agricultural runoff is disappearing at a faster rate than air pollution disappeared in the 1970’s with the development and introduction of mitigation technologies.
Farmers are constantly looking for ways to both reduce input costs and the consequences of inputs, and agricultural researchers have been leading the way at least since the end of the Second World War.
When it comes to fertilizer, and specifically phosphorus fertilizer in wheat, a team of researchers have made promising strides.
Phosphorus is essential to plant growth. One of the problems with crop production is that much of the phosphorus is taken from the soil with the crop. Without replacing the vital element the soil will eventually be unable to support plant growth. Therefore, fertilizer containing phosphorus must be applied.
Unfortunately, phosphorous is a finite resource, and is rather difficult and expensive to concentrate into a fertilizer product. It’s also quite hard to target the proper concentration at the root of the plant, where it is taken up for use. Therefore, to get enough phosphorus to the root, farmers must apply more than is strictly required by the plant. Some of the excess phosphorus always washes away and eventually runs downstream where it contributes to algal blooms in ponds, lakes, and even in the sea.
Researchers in Pakistan (Samreen Mohsin, et al. “Extracellular Secretion of Phytase from Transgenic Wheat Roots Allows Utilization of Phytate for Enhanced Phosphorus Uptake.” published in the journal Molecular Biotechnology on June 30, 2017) have recently developed a strain of wheat which has the ability to access phosphorus contained in the enzyme phytate, which is abundant in many soils. Unfortunately, plants generally lack the ability to use phytate.
The researchers wondered if an enzyme called phytase, which is produced by the fungus Aspergillus japonicus, might be one key to allowing wheat plants to use the phosphorus which is usually locked away in phytate.
Using transgenic techniques, the researchers inserted the fungal gene for phytase into wheat, adjusting the genetics to cause it to be active only in root tissue and to cause the roots to express the enzyme into the surrounding soil. The theory was that phytase expressed from the plant root would break down phytate in the soil, freeing up phosphorus to be taken up as a micronutrient.
The results were quite good, with the genetically engineered wheat plants growing better and containing more phosphorus than non-modified control plants grown in the same soil
Results of the study show that the new wheat strain can grow quite well in soil containing phytate but otherwise deficient in phosphorus. If field trials of the modified wheat plants are successful, farmers could be soon taking another step in reducing the use of fertilizer and guarding the environment.