Unveiled the effect of gravity on the growth of plants

An international team with the participation of the Plant Cell Nucleolus, Proliferation & Microgravity group, led by Dr. Javier Medina at CIB, has shown in two works recently published in the journals NPJ Microgravity and Scientific Reports that microgravity conditions similar to those of Mars or the Moon, as well as the hypergravity that would occur in exoplanets, affect the cellular development of the plants producing a premature cell division that causes their size to be reduced.

In these studies, the model plant Arabidopsis thaliana has been used, which was previously exposed to microgravity in successive experiments on the International Space Station (ROOT, GENARA, Seedling Growth) carried out by this same group. Now, they have used new simulators that allow to reproduce the gravity of the Moon (1/6 of the Earth, 0.18g) and Mars (something more than 1/3, 0.37g) or generate hypergravity with a double value of the Earth (2g) to reproduce the situation in possible exoplanets.

The study published in NPJ Microgravity shows that the rate of division and growth of Arabidopsis meristematic cells, their stem cells, are strongly decompensated by the absence of gravity reproducing alterations as strong, or even higher, than those observed previously in the experiments made on the Space Station.

In addition, in the work published in Scientific Reports, cell cultures of plants were analyzed to study the molecular mechanisms by which the cell proliferation rate is altered in different gravity conditions. Immunofluorescence assays with an anti-methyl cytosine antibody to study the epigenetic alteration of DNA methylation show, consistent with the previous results, that microgravity causes a strong effect of increased methylation, the gravity of Mars produces an intermediate effect and the hypergravity practically does not modify the control pattern 1g.

Although the results obtained in the simulators must be validated in real microgravity, they can be useful in order to improve the growth conditions of the plants that will be part of the life support of astronauts in future space travels.

The two experiments, in which Centro de Investigaciones Biológicas,has participated, have been developed in the context of international collaboration projects funded by the European Space Agency (ESA).

References:
Novel, Moon and Mars, partial gravity simulation paradigms and their effects on the balance between cell growth and cell proliferation during early plant development. Aránzazu Manzano, Raúl Herranz, Leonardus A. den Toom, Sjoerd te Slaa, Guus Borst, Martijn Visser, F. Javier Medina and Jack J. W. A. van Loon (2018) NPJ Microgravity. Doi:10.1038/s41526-018-0041-4

Simulated microgravity, Mars gravity, and 2g hypergravity affect cell cycle regulation, ribosome biogenesis, and epigenetics in Arabidopsis cell cultures. Khaled Y. Kamal, Raúl Herranz, Jack J. W. A. van Loon and F. Javier Medina. (2018) Scientific Reports. Doi:10.1038/s41598-018-24942-7

More information: CSIC Press Release (in spanish)