AUTHOR=Kuya Noriyuki , Nishijima Ryo , Kitomi Yuka , Kawakatsu Taiji , Uga Yusaku 

TITLE=Transcriptome profiles of rice roots under simulated microgravity conditions and following gravistimulation

JOURNAL=Frontiers in Plant Science

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1193042

DOI=10.3389/fpls.2023.1193042

ISSN=1664-462X

ABSTRACT=<p>Root system architecture affects the efficient uptake of water and nutrients in plants. The root growth angle, which is a critical component in determining root system architecture, is affected by root gravitropism; however, the mechanism of root gravitropism in rice remains largely unknown. In this study, we conducted a time-course transcriptome analysis of rice roots under conditions of simulated microgravity using a three-dimensional clinostat and following gravistimulation to detect candidate genes associated with the gravitropic response. We found that <italic>HEAT SHOCK PROTEIN</italic> (<italic>HSP</italic>) genes, which are involved in the regulation of auxin transport, were preferentially up-regulated during simulated microgravity conditions and rapidly down-regulated by gravistimulation. We also found that the transcription factor <italic>HEAT STRESS TRANSCRIPTION FACTOR</italic> A2s (<italic>HSFA2</italic>s) and <italic>HSFB2</italic>s, showed the similar expression patterns with the <italic>HSP</italic>s. A co-expression network analysis and an in silico motif search within the upstream regions of the co-expressed genes revealed possible transcriptional control of <italic>HSP</italic>s by HSFs. Because HSFA2s are transcriptional activators, whereas HSFB2s are transcriptional repressors, the results suggest that the gene regulatory networks governed by HSFs modulate the gravitropic response through transcriptional control of <italic>HSP</italic>s in rice roots.</p>