Abstract
Static magnetic field (SMF) plays important roles in biological processes of many living organisms. In plants, however, biological significance of SMF and molecular mechanisms underlying SMF action remain largely unknown. To address these questions, we treated Arabidopsis young seedlings with different SMF intensities and directions. Magnetic direction from the north to south pole was adjusted in parallel (N0) with, opposite (N180) and perpendicular to the gravity vector. We discovered that root growth is significantly inhanced by 600 mT treatments except for N180, but not by any 300 mT treatments. N0 treatments lead to more active cell division of the meristem, and higher auxin content that is regulated by coordinated expression of PIN3 and AUX1 in root tips. Consistently, N0-promoted root growth disappears in pin3 and aux1 mutants. Transcriptomic and gene ontology analyses revealed that in roots 85% of the total genes significantly down-regulated by N0 compared to untreatment are enriched in plastid biological processes, such as metabolism and chloroplast development. Lastly, no difference in root length is observed between N0-treated and untreated roots of the double cryptochrome mutant cry1 cry2. Taken together, our data suggest that SMF-regulated root growth is mediated by CRY and auxin signaling pathways in Arabidopsis.
Highlights
All organisms living on the earth are inevitably subject to an action of the geomagnetic field (GMF), which can be represented by a three-dimensional vector called intensity, inclination and declination
To investigate whether plant growth and development are affected by moderate static magnetic field (SMF) intensity[34], we vertically grew Arabidopsis seedlings in petri dishes that were closely attached to the side of a magnet, which is a cube with each side length of 10 cm and produces around 600 mT magnetic field at the surface of the north (N) and south (S) poles
We did not find significant effects of 300 mT SMF on seedling growth, compared to the control (Supplementary Fig. S3). These results suggest that responses of Arabidopsis young seedlings to SMF stimuli are influenced by its strength and orientation, and by different tissues
Summary
All organisms living on the earth are inevitably subject to an action of the geomagnetic field (GMF), which can be represented by a three-dimensional vector called intensity, inclination and declination. Reversing the GMF polarity greatly inhibits growth of hypocotyls and roots, and modulates gene expression, suggesting that GMF might have been a factor contributing to plant evolution over geological timescales[9]. Under the near-null magnetic field (NNMF, ≤40 nT) condition, Arabidopsis CRYs were shown to be involved in delayed flowering via modulating GA and auxin signaling[5,6,7,8], and in changes of gene expression[24,25]. We used Arabidopsis as a model system to investigate effects of SMF on seedling growth, and found that SMF promotes root growth in an intensity- and direction-dependent manner via increasing auxin concentrations at the root tip, providing a new system to elucidate molecular mechanisms of plant responses to SMF in the future
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
