Root hairs develop distinctly from many other plant cell types. Typically, the two stages of root hair production are cell-fate determination and growth. First, epidermal cells develop to stay a rank-and-file epidermal cell (atrichoblast) or to become a root hair cell (trichoblast). A typically parenchymatous epidermal cell generates a localized bulge during the development phase, which is later extended by tip growth.
However, once the tip-growth rate becomes steady, the diffuse growth of the rest of the epidermal cell stops. Physiology impacts both phases of the underlying developmental program, making the number of root hairs produced by a given root at a given period and their length and character a sensitive function of the environment.
Scientists from Washington State University found a plant gene that drives the growth of root hairs. They identified a gene called ‘BUZZ’ that causes faster-growing, denser webs of roots and may also determine how plants find and use nitrates, a prime nitrogen source essential to plant growth.
This BUZZ gene plays a vital role in adjusting root growth- both the rate and lateral root initiation — in response to the nitrate concentration in nearby soil. Finding the gene was difficult because it is expressed at deficient levels and has never been documented.
Washington State University researcher Karen Sanguinet said, “Nitrate runoff and nitrogen use efficiency are some of the preeminent issues facing agriculture. Suppose you can understand the genetic mechanisms that control nitrate uptake and signaling and how plants can better use nitrate. In that case, it’s advantageous for agriculture, soil, water, fertilizer application, and the entire nitrogen cycle.”
“Expression of the BUZZ gene is turned up in response to nitrate, urea, and ammonia, presumably so roots can find nitrogen in the soil. Loss of the gene shows a foraging root phenotype even when the nitrate supply is plentiful.”
“For such a sensitive response, the plant needs a discreet and tightly regulated gene. That’s what made it so hard to find.”
Given the similarities in sequence amongst grasses, it is crucial to identify the gene in a model grass species because its function is probably conserved. Thus, it refers to agricultural products like wheat, rice, corn, and barley. A gene that could improve these plants’ ability to locate and utilize nitrate could have a significant effect because these crops are essential for feeding the world’s population.
Now that the biological function of the BUZZ gene has been identified and confirmed, scientists are learning more about this recently discovered mechanism.
Sanguinet said, “Now we’re finding cool stuff about how plants use the particular gene to nitrate and root systems. Figuring out how plants work is the joy of why we do this.”
Journal Reference:
- Thiel A. Lehman, Miguel A. Rosas, Rhoda A. T. Brew-Appiah et al. BUZZ: an essential gene for postinitiation root hair growth and a mediator of root architecture in Brachypodium distachyon. New Phytologist. DOI: 10.1111/nph.19079