Because plants do not have the same ability as animals to replace dead cells, they rely on different methods of managing DNA damage without stalling growth.
Until now the mechanism by which plants keep genomes stable while also allowing for continued growth in fluctuating environments has remained a mystery. However, a research team in Japan, led by the Nara Institute of Science and Technology, has finally found the answer!
Plant growth is largely driven by root function. Because root development is highly responsive to changes in underground conditions, environmental stresses that hinder root growth can ultimately cause DNA damage.
“Plants actively respond to DNA damage, and these responses are controlled by the cell cycle checkpoint mechanism,” explained Project Leader Masaaki Umeda.
“The cell cycle is stopped at a certain stage so that DNA can be repaired, or in extreme cases, cell death initiated. What we wanted to know was how the DNA damage responses are organised to allow continuous root growth.”
The team discovered that plants achieve this through the combined control of two hormones — auxin and cytokinin. In doing so, plants are able to organise different responses to damage, minimising cell death and maintaining growth.
The scientists found a decrease in auxin triggers stem cell death, while an increase in cytokinin supports a process known as endoreplication — a cell cycle variant whereby the genome is duplicated without cell division.
These significant findings will have broad application in future research into plant growth and development in extreme environments.
Source: Science Daily
