The signalling of the Fe status in the mesophyll cells, especially in the chloroplasts
is hardly known. Although nitric oxide (NO) is connected to the regulation of root
Fe uptake, NO signal has not been associated with the foliar Fe homeostasis so far.
NO can initiate post-translation modification of proteins. Moreover, NO signal is
known to affect the developmental senescence, the process that is characterised by
the decomposing of chloroplasts and liberation of Fe from the photosynthetic apparatus.
Based on our in silico analysis, plastidial Fe homeostasis elements that are involved
in Fe storage and release are unlikely to be affected by NO induced post-translational
modification, whereas plastidial Fe uptake and incorporation machinery elements are
possible NO targets. Microscopy X-ray fluorescence (μXRF) analysis of S-nitrosogluthatione
reductase overexpressing (GSNOR-ox) and nitric oxide associated (noa) 1 defective
lines showed the lack of significant plastidial Fe accumulation at the initiation
of developmental senescence.
This work was supported by the grant financed by the National Research, Development
and Innovation Office, Hungary (NKFIH K-135607) and by the beam time allocation No.
LS-3039 of European Synchrotron Radiation Facility.
