The photosynthetic apparatus requires the incorporation of a significant amount of
transition metal cofactors, among others Fe containing FeS clusters and heme groups.
Despite the importance of Fe loading into chloroplasts, transition metal allocation
in cells is not a unidirectional process, since eukaryotic cells perform a dynamic
structural reorganisation in order to adapt to the challenges of the environment.
Nevertheless, the control over Fe allocation to the cell compartment in the mesophyll
remained poorly known. Since nitric oxide (NO) has been found to be an important factor
in the coordination of the root Fe uptake and homeostasis, its role in the mesophyll
cell Fe homeostasis is also proposed. Cryosectioned mesophyll cells of early senescent
Arabidopsis thaliana lines affected in the NO homeostasis by defects of NO biosynthesis
(noa1) and affected in the S-nitrosoglutathione reductase enzyme (GSNOR, deficient
and overexpressing) were to particle induced X-ray emission (μPIXE), low energy X-ray
fluorescence microscopy (LEXRF), and high energy (HE) XRF microscopy. The HEXRF dataset
is accessible at Solti et al. (2025). K-means clustering of the Fe signal distribution
approved that perturbed NO signaling resulted in a lowered plastidial Fe allocation
in the early senescent stage that underlines impact and the pro-senescence property
of the NO signaling nature on the plastidial Fe accumulation.
Reference
Solti Á & al. (2025). ESRF. doi.org/10.15151/ESRF-ES-790328283 [Dataset].
This work was supported by the grant K-135607 of NKFIH, Hungary. Á.S. was supported
by the János Bolyai Scholarship of the Hungarian Academy of Sciences (BO-00113-23-8).
We acknowledge the European Synchrotron Radiation Facility (ESRF) for provision of
synchrotron radiation facilities under proposal number LS-3039. Instrument center
access was financed under ReMade@ARI PID 34653 (financed as part of HORIZON-INFRA-2021-SERV-01,
101058414, 10039728 and 22.0018). We acknowledge Elettra-Sincrotrone, Trieste, Italy
for the beam time access (20245567).
