Molecular Compass For Cell Orientation

Plants have hormone Auxin which helps in providing positional information to growing cells and regeneration.  The mystery was unsolved till now that how it coordinates in cell orientation.

Molecular Compass for Cell Orientation

Previous concepts included that it is only responsible for transcriptional signal transmission. But now the mystery has been resolved and scientists have discovered that Auxin is also involved in cell orientation in tissues, in wound healings and regeneration. They also found that signal transmission is non- transcriptional to some extent.


Plants have many veins that help in the transportation of nutrients in their bodies. These veins are present in a highly organized and complex manner. The plants have hormone auxin which travels directionally from cell-to-cell and it provides cells the information about their suitable position, coordinating them during regeneration and development of veins.

This hormone is essential for plant growth as it promotes elongation in stem and cells and diminishes the lateral buds growth. Auxins play an important role in Apical Dominance e.g. Indole Acetic Acid.

Previous perception of Auxins 

By previous studies, it was believed that Auxins are only responsible for sending signals in the cell nucleus for the purpose of shaping embryos and to regulate gene transcription as plant grows.

Earlier Scientists have shown that auxin is used as a sign of narrowing of the arteries and is responsible for arranging the tissues in the formation of stored arterial patterns. However, scientists find it difficult to understand how cells remove the encryption of this chemical signal in a cellular response.

Till now it was an unsolved mystery to the scientists that how cells help in translating auxin signal into a formation of a highly organized vascular system Difficulty in solving mystery of Auxins: Auxin hormones allow bending of roots in one direction only while inhibiting the growth in other direction so that concentration of this hormone remains in one direction only. 

As the seeds start to germinate, plant roots quickly establish direction and they bend in such a direction to grow deep inside soil. The main difficulty faced by scientists was extreme quick reaction time.

New Discovery from an Old Pathway      

A group of scientists were trying to solve this mystery.  A team of scientists was trying to solve this mystery. Scientists from Prof. Jiri Friml’s team at IST Austria recently discovered how the hormone auxin releases newly formed arteries. “Auxin determines which cells will divide into blood vessels and then classifies them to form complex vascular patterns,” explains Jakub Hajný, who led the study.

The TIR1 receptor is needed to find a new way .The previous study was transcriptional but latest method includes non- transcriptional signaling without ignoring the original transcriptional pathway.  

They find molecular mechanisms that detect local aggression and allow cells to adjust their behavior to coordinate vascular formation and regeneration. This process also has its application to healing wounds and can lead to the development of more resistant mechanical plants and other agricultural impacts.

Cell Orientation in Tissues

The group under Friml identified the proteins which are responsible for this mechanism, called CAMEL and CANAR. These proteins play the role of Auxin sensors.

The CAMEL/CANAR both recognise the auxin concentration in the neighborhood and allows cells to coordinate their orientations to create continuous veins.

“It is basically a molecular compass for cell orientation, only instead of a magnetic field; it detects auxin concentration,” explains Jakub Hajný. Thus, the team discovered molecular machinery underlying auxin-mediated vein formation and regeneration.                                                                                                           

Flip Over microscope and liquid-filled Micro channels:

 In the previous method, sample of Auxin was directly mounted in the sample but with this those essential seconds can’t be measured which were important for study. For capturing the reaction time the scientists had to change the solution which the roots grow in.

In the new mechanism the roots were grown in microscopic channels filled with the desired liquid. After that they poured this mixture with Auxin over the microscope to examine.

Wound Healing   For the investigation of wound healing, scientists took a thale crust root and applied a cut with the help of laser. 

They then used a microscope to track the cells in the wound which were regenerating. The scientists came to know that Auxin, a hormone responsible for plant growth and development also plays an essential role in wound healing. Scientists found that it only develops in those cells which are directly in contact with wounds.

  • Effect of pressure during generation:

Certain change in pressure was recorded by scientists near the wounding cells. When they reduced the cellular pressure before cutting the plant following events occurred; Pressure difference diminished leading to weakening of regeneration .

They modified it with different chemical treatments and then they identified that pressure changes and the auxin concentration both act as governing processes for wound healing.

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