Transcriptomic responses of Arabidopsis thaliana lines WS and sku5 to the Blue Origin NS-12 and Virgin Galactic VP-03 suborbital flights

The increasing availability of flights on suborbital rockets creates new avenues for the study of spaceflight effects on biological systems, in particular the transitions between hypergravity and microgravity. This paper presents an initial comparison of the responses of Arabidopsis thaliana to suborbital and atmospheric parabolic flights as an important step toward characterizing these emerging suborbital platforms and their effects on biology. Transcriptomic profiling of the response of the Arabidopsis ecotype Wassilewskija (WS) to the aggregate spaceflight experiences in the Blue Origin New Shepard and Virgin Galactic SpaceShipTwo rockets revealed that the transcriptomic load induced by flight differed greatly between the two flights, yet was biologically related to traditional parabolic flight responses. The sku5 skewing mutant and 14-3-3κ:GFP regulatory protein overexpression lines each showed altered intra-platform responses compared to WS in the Blue Origin and parabolic flights, respectively. An additional parabolic flight using the F-104 Starfighter showed that the response of 14-3-3κ:GFP to flight was modulated in a similar manner to the WS line. Despite the differing genotypes, experimental workflows, flight profiles and platforms, alteration of gene expression remodeling central metabolic processes was commonly observed as a response to the flights. The processes included carbon and nitrogen metabolism, branched-chain amino acid degradation, and hypoxic responses. The timing and directionality of differentially-expressed genes involved in the conserved pathways differed among the platforms. The data presented herein highlight the potential for various suborbital platforms to contribute insights into biological responses to spaceflight, and further suggest that in-flight fixation during suborbital experiments will provide insights into responses to each phase of flight. Multiple genotypes of Arabidopsis thaliana seedlings were flown on either the Virgin Galactic SpaceShipTwo (VG VP-03; Col-0 and WS) or Blue Origin New Shepard (BO NS-12; WS and sku5) suborbital flight platforms. Plates containing the seedlings, 10 days and 11 days old in VG and BO, respectively, were wrapped in Duvetyne™ Black-Out cloth and mounted to the internal wall of the FLEX imaging system payload used in these flights. Gene expression was compared between the ground control and spaceflight-exposed seedlings via RNA-Seq analysis of extracted total RNA from the roots of these seedlings.