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Magnetoreception in Plants

FIGURE 5.6 Schematic representation of gene expression patterns in Arabidopsis thaliana leaves and foral meri­

stem under near-null magnetic feld (NNMF). Leaf gene regulation of clock, photoperiod pathway, vernalization

pathway, gibberellin pathway, and regulatory network are depicted during early, intermediate, and late stages of

fowering. An early downregulation of clock, photoperiod, gibberellin, and vernalization pathways is accompanied

by a downregulation of AP1 and GA20ox. In the foral meristem, NNMF determines an early downregulation of

the gibberellin pathway, AGL24 and AP1, with a signifcant upregulation of LFY, FD, and SVP. In intermediate

times, AGL24 is upregulated, whereas at late times AP1 is upregulated. Te gibberellin pathway is downregulated

in early and intermediate times, whereas no regulation is found in late times. In both leaves and foral meristem

data, upregulation is shown in black areas, downregulation in gray areas, and no regulation in white. According to

Fornara et al. (2010), Jaeger et al. (2013), and Valentim et al. (2015). (Modifed from Agliassa et al. (2018a).)

NAC050 and NAC052 were also signifcantly downregulated. Terefore, exposure of A. thaliana to

NNMF causes a delay in the transition to fowering due to a combined regulation of leaves and foral

meristem genes (Figure 5.6).

An early downregulation of clock, photoperiod, gibberellin, and vernalization pathways is accom­

panied by a downregulation of AP1 and GA20ox. FLC is upregulated by NNMF in early fowering

induction. In the foral meristem, the strong downregulation of FT and FLC in early phases of foral

development is accompanied by the downregulation of the gibberellin pathway and the upregulation of

FD, SVP, and the transcription factor LFY. Te common downregulation of AP1 in both foral meristem

and leaves is associated with the delay in fowering. In the foral meristem and leaves, the progressive

upregulation of AGL24, AP1, GI, and SVP from early to late phase of plant development is correlated to

the delay of fowering. Tese events are followed by the progressive reduction of gibberellin pathway

downregulation. Tese results indicate that NNMF does not prevent fowering, and that variations of

the MF are sufcient to modulate specifc genes in the early stages of fower induction that are associated

with the observed delay. However, the gene expression regulation might not refect the post-translational