Insights from plant research in space and ground-based facilities advance our understanding of fundamental biological processes and inform future space exploration and colonization efforts. This presentation covers recent advancements and lingering inquiries in plant gravitropism research in altered gravity environments.
Gravitropism is the ability of plants to sense and respond to gravitational forces, which is fundamental to their growth and development. However, its precise molecular mechanisms and the proteins involved are still unclear. International Space Station (ISS) experiments have provided new insights into plant gravity perception. Furthermore, studies involving drop towers, parabolic flights and sounding rocket campaigns have signified the role of short-term microgravity exposures on plant gravitropic responses, providing valuable data for future long-duration space missions.
Moreover, emerging technologies such as advanced imaging techniques, a wide variety of omics approaches and high-throughput phenotyping platforms promise to unveil novel insights into the intricacies of plant gravitropism in space and on the ground. Leveraging microgravity platforms such as the FLUMIAS microscopes aboard the ISS or on TEXUS rockets and optogenetic systems like CaMPARI enable real-time visualization of cellular processes, facilitating the exploration of gravitropic signaling pathways with unprecedented detail and throughput.
Despite recent advancements, several questions persist regarding the molecular mechanisms underlying plant gravitropism. Key areas of investigation include deciphering how altered gravity affects amyloplast dynamics, calcium signaling, and gene expression patterns in plant cells. Additionally, understanding how plants adapt long-term growth strategies in response to varying gravitational conditions remains a critical challenge. Continued interdisciplinary collaborations and innovative research endeavors are essential to address these open questions and pave the way for the successful cultivation of plants in extraterrestrial environments.

Introduction
The European life science community in space research has been always limited in numbers but fully devoted to microgravity research leading the international scenario in particular organisms. In the last fifteen years, the financial crisis, together with the emergence of private partners for NASA, made ESA related researchers vulnerable to the lack of manned mission launch capabilities. This has particularly affected the Space Omics research in which ESA funded activities have been reduced. European PIs have been forced to partner up with international colleagues to keep the pace in their research goals, in some cases with outstanding results (Herranz et al., 2019; Vandenbrink et al., 2019).

Methods
Our Space Omics Topical Team was created as an offshoot of a successful NASA initiative called Genelab (Ray et al., 2019) repository for Omics data as part of the Analysis Working Groups (AWG’s). On the Genelab AWG symposium in 2019 they organized bilateral talks between each other to coordinate actions on our side of the Atlantic Ocean (Deane et al., 2022). Later we integrated our efforts with those of the International Standards for Space Omics Processing (ISSOP), a consortium of scientists who develop, share, and encourage sample processing standardization and metadata normalization of spaceflight “omics” experiments (Rutter et al., 2020).

Results
Discovering the adaptation mechanisms of plants to the space environment is essential for supporting human space exploration. Transcriptomic analyses allow the identification of adaptation response pathways by detecting changes in gene
expression at the global genome level caused by the main factors of the space environment, namely altered gravity and cosmic radiation. A number of transcriptomic studies carried out from plants grown in spaceflights and in different ground-based microgravity simulators is shown (Figure 1). Despite differences in plant growth conditions, these studies have shown that cell wall remodeling, oxidative stress, defense response, and photosynthesis are common altered processes in plants grown under spaceflight conditions. European scientists have significantly contributed to the acquisition of this knowledge, e.g., by showing the role of red light in the adaptation response of plants (EMCS experiments) and the mechanisms of cellular response and adaptation mostly affecting cell cycle regulation, using cell cultures in microgravity simulators (Kamal et al., 2019a; Kamal et al., 2019b).

Conclusions
Here we will disclose our final recommendations (Manzano et al., 2023) with a particular emphasis in the Plant relates experimentation including the development of payloads to replace EMCS.