When most people think of a plant, they picture stems, leaves, flowers, and all the parts that are visible above ground. But the authors were more interested in the hidden half of the plant that is buried beneath the soil. Roots: they may be out of sight, but they play critical roles, anchoring the plant and taking up water and nutrients.
Now, the researchers have pieced together new details in the cascade of events that guide root growth -- research that could lead to more productive crops optimized for different soil types.
As a root tunnels through the soil, stem cells in the root's tip must determine whether to divide and produce more of the same stem cells, or differentiate into other cell types, based on their location within the root tissue. In a study published in the journal Nature, the researchers show that cells get some of the information they need from substances that are usually thought to be harmful.
Natural byproducts of cellular respiration, molecules called "reactive oxygen species" have long been described as stress signals that can cause tissue damage if left unchecked. But they also play a role in cell signaling.
In a study of the small flowering plant Arabidopsis thaliana, the researchers report that root growth is partly regulated by interactions between two types of reactive oxygen species, superoxide and hydrogen peroxide, as they build up in different regions of the root tip.
"What we did was map out, from signal to response, how these supposedly toxic chemicals are harnessed for a signaling process," the senior author said.
Roots grow longer thanks to a small region of stem cells at the end of each root that produces a constant supply of new cells behind it, propelling the root tip further downward through the soil like the head of a bullet. The daughter cells that are left behind stay put, and eventually stop dividing and start to specialize.
How fast a root grows depends on the balance between two opposing cues: those that encourage these stem cells to keep multiplying, and those that tell them to put the brakes on proliferating and change gears to specialize. The researchers identified a protein called RITF1 that, when activated, triggers this developmental switch.
The RGF1-receptor pathway controls the distribution of reactive oxygen species (ROS) along the developmental zones of the Arabidopsis root. The authors identify a previously uncharacterized transcription factor, RGF1-INDUCIBLE TRANSCRIPTION FACTOR 1 (RITF1), that has a central role in mediating RGF1 signalling. Manipulating RITF1 expression leads to the redistribution of ROS along the root developmental zones. Changes in ROS distribution in turn enhance the stability of the PLETHORA2 protein, a master regulator of root stem cells.
The protein works by controlling where the two reactive oxygen species concentrate within the growing tip of the root. These chemical signals tell the surrounding cells what course of action to take next. Cells exposed to higher amounts of superoxide keep dividing and producing new cells, while those that get a heavy dose of hydrogen peroxide differentiate, with a zone of transition where the two overlap.
"We don't have all the pieces yet," the author said, "but there are a lot more steps of the process that are now known through this work than were known before."
"Reactive oxygen species aren't just toxic chemicals," the author said. "They serve important roles as regulators of a developmental process, going from a stem cell to fully differentiated tissue."
https://today.duke.edu/2019/12/making-root
https://www.nature.com/articles/s41586-019-1819-6
Reactive oxygen species and plant root growth
- 6,341 views
- Added
Edited
Latest News
Mutations in noncoding DNA…
By newseditor
Posted 24 Apr
More influence of environme…
By newseditor
Posted 24 Apr
The assembly of the human c…
By newseditor
Posted 24 Apr
Wiring of the human neocortex
By newseditor
Posted 24 Apr
Abusive drugs hijack natura…
By newseditor
Posted 23 Apr
Other Top Stories
The gene to which we owe our big brain
Read more
Regulation and development of hematopoietic stem cells
Read more
Human brain organoids influence rat behavior
Read more
How neurons from PTSD patients react to stress
Read more
Common regulators of different direct reprogramming
Read more
Protocols
A programmable targeted pro…
By newseditor
Posted 23 Apr
MemPrep, a new technology f…
By newseditor
Posted 08 Apr
A tangible method to assess…
By newseditor
Posted 08 Apr
Stem cell-derived vessels-o…
By newseditor
Posted 06 Apr
Single-cell biclustering fo…
By newseditor
Posted 01 Apr
Publications
Massively parallel screen u…
By newseditor
Posted 24 Apr
Distinct genetic and enviro…
By newseditor
Posted 24 Apr
Hippocampus-to-amygdala pat…
By newseditor
Posted 24 Apr
Integrative spatial analysi…
By newseditor
Posted 24 Apr
Time-series reconstruction…
By newseditor
Posted 24 Apr
Presentations
Hydrogels in Drug Delivery
By newseditor
Posted 12 Apr
Lipids
By newseditor
Posted 31 Dec
Cell biology of carbohydrat…
By newseditor
Posted 29 Nov
RNA interference (RNAi)
By newseditor
Posted 23 Oct
RNA structure and functions
By newseditor
Posted 19 Oct
Posters
A chemical biology/modular…
By newseditor
Posted 22 Aug
Single-molecule covalent ma…
By newseditor
Posted 04 Jul
ASCO-2020-HEALTH SERVICES R…
By newseditor
Posted 23 Mar
ASCO-2020-HEAD AND NECK CANCER
By newseditor
Posted 23 Mar
ASCO-2020-GENITOURINARY CAN…
By newseditor
Posted 23 Mar