Transcriptomic Analysis Reveals the Effects of Microgravity on Rice Calli on Board the Chinese Spaceship Shenzhou 8

Abstract

Rice calli were loaded onto the stationary and rotating platforms of a biological incubator (SIMBOX) during spaceflight and ground control experiments. The calli in the SIMBOX were fixed with RNAlater in space after a 324-h spacecraft flight, as well as on the ground at the same time point in a ground control experiment. Microgravity-responsive (MR) transcripts were identified by a comparison of the spaceflight controls (F-μg) with the 1-g ground controls (G-1g) and 1-g inflight controls (F-1g). MapMan analysis was used to classify 955 MR transcripts. These transcripts mainly belonged to the following categories: cell wall modification and metabolism, glycolysis and the tricarboxylic acid (TCA) cycle, transcription factors, protein modification and degradation, hormone metabolism and signalling, calcium regulation, receptor-like kinase activity, and transporters. Here, we focused on the effects of microgravity on the plant cell wall and discussed the relationship between the variation in the cell wall and plant cell growth under microgravity.