2020 Volume 34 Pages 12-33
The present paper is a comprehensive report on the Auxin Transport space experiment: the analysis of gravity response and attitude control mechanisms of plants under microgravity conditions in space on the International Space Station. The Auxin Transport space experiment was conducted in 2016 and 2017 in the Japanese Experiment Module (JEM) on the International Space Station (ISS), with the principal objective being integrated analyses of the growth and development of etiolated pea (Pisum sativum L. cv Alaska) and maize (Zea mays L. cv Golden Cross Bantam) seedlings under true microgravity conditions in space relative to polar auxin transport. To clarify auxin dynamics at molecular levels, gene expression of PsPIN1 and ZmPIN1a mRNA, and their products detected by immunohistochemistry were also investigated. In addition, the use of microarray data technology with Medicago ( Medicago truncatula ) microarrays to characterize global changes in the transcript abundance of etiolated Alaska pea seedlings grown under microgravity conditions in comparison with those under artificial 1 G conditions on the International Space Station was reported here. Comprehensive analyses of endogenous plant hormones in etiolated pea and maize seedlings grown under microgravity conditions in space as well as on 1 G conditions on Earth have already performed in the space experiment.