Controlled ecological life support systems (CELSS) will be an important feature of long-duration space missions of which higher plants are one of the indispensable components. Because of its pivotal role in enabling plants to cope with environmental stress, interplant communication might have important implications for the ecological stability of such CELSS.

However, the manifestations of interplant communication in microgravity conditions have yet to be fully elucidated.

BIAN Po's study team in Institute of Technical Biology & Agriculture Engineering, Hefei Institutes of Physical Science (CAHIPS), made great progress in investigating the effect of microgravity on UV-C-induced interplant communication in plants. And their work was published in Mutation Research/ Fundamental and molecular mechanisms of mutagenesis.  

In the study, a well-established Arabidopsis thaliana co-culture experimental system, in which UV-C-induced airborne interplant communication is evaluated by the alleviation of transcriptional gene silencing (TGS) in bystander plants, was placed in microgravity modeled by a two-dimensional rotating clinostat.

Compared with plants under normal gravity, TGS alleviation in bystander plants was inhibited in microgravity.

In addition to the specific TGS-loci, interplant communication-shaped genome-wide DNA methylation in bystander plants was also altered under microgravity conditions.

These results indicate that interplant communications might be modified in microgravity. Time course analysis showed that microgravity interfered with both the production of communicative signals in UV-C-irradiated plants and the induction of epigenetic responses in bystander plants.

This was further confirmed by the experimental finding that microgravity also prevented the response of bystander plants to exogenous methyl jasmonate (JA) and methyl salicylate (SA), two well-known airborne signaling molecules, and down-regulated JA and SA biosynthesis in UV-C-irradiated plants.

Those work were supported by the grants from National Natural Science Foundation of China, the Youth Innovation Promotion Association of Chinese Academy of Sciences and the International S & T Cooperation Program of China.

Effect of microgravity on the UV-C-induced interplant communication of Arabidopsis thaliana. (A) Schematics of the co-culture experimental system for airborne interplant communication and microgravity treatment; (B) The repressive effects of modeled microgravity on UV-C-induced interplant communication; (C) Effects of microgravity on the JA and SA signaling pathways in UV-C-irradiated plants. (Image by WANG Ting)