Jorge has focused his research career on how plants respond to metal stress, in particular how they cope with iron deficiency.
During his PhD at the University of Zaragoza (2007 – 2012), Jorge studied proteomics changes in iron-deficient plants. In addition, he discovered that Medicago truncatula secretes flavins into the rhizosphere when iron is limiting, including a novel hydroxylated flavin compound (Rodríguez-Celma et al., 2011 Plant Cell Physiol 52:2173-89).
As a postdoctoral researcher at the Academia Sinica in Taipei (2012 – 2014), Jorge applied transcriptomics to iron deficiency responses in Medicago and Arabidopsis. Using network analysis, he showed that specific coumarin biosynthetic genes are associated with iron uptake in Arabidopsis (Rodríguez-Celma et al., 2013 Plant Physiol 162:1473-85). The production of such specialised secondary metabolites is crucial for mobilisation of poorly soluble iron hydroxides. His findings have since been taken further by several research groups and is highly cited as pioneering work.
Jorge also identified several uncharacterised genes with a role in iron homeostasis. These include the BRUTUS-LIKE genes BTSL1 and BTSL2, encoding hemerythrin E3 ubiquitin ligases, that are expressed predominantly in roots.
As a Marie Curie Fellow and Postdoctoral Scientist in the Balk laboratory (2015 – 2019), Jorge is unravelling the precise biochemical function of BTSL1 and BTSL2. The proteins were found to bind iron in their N-terminal hemerythrin domains. Moreover, we find that BTSL1 and BTSL2 are responsible for proteasomal degradation of FIT. FIT is a key transcription factor in iron uptake and is a hub for regulatory signals that affect the iron deficiency response. The btsl double mutant fails to degrade FIT when iron is resupplied, resulting in the accumulation of toxic amounts of iron in roots and leaves (Rodríguez-Celma et al., 2017 bioRxiv:231365; Rodríguez-Celma et al., 2019 Front Plant Sci 10:98).
On the more applied side, Jorge has optimised the extraction of ferritin from pea seeds for its potential use as a treatment for iron deficiency anaemia in humans (Moore et al., 2018 Sci Rep 8:6865; Perfecto et al., 2018 J Nutr 148:1229-35) and developed reporter plants that emit light when they suffer from iron deficiency.
Rodriguez-Celma J., Connorton J. M., Kruse I., Green R. T., Franceschetti M., Chen Y. T., Cui Y., Ling H. Q., Yeh K. C., Balk J. (2019)Arabidopsis BRUTUS-LIKE E3 ligases negatively regulate iron uptake by targeting transcription factor FIT for recycling.Proceedings of the National Academy of Sciences of the United States of AmericaPublisher's version: 0027-8424
Rodriguez-Celma J., Chou H., Kobayashi T., Long T. A., Balk J. (2019)Hemerythrin E3 ubiquitin ligases as negative regulators of iron homeostasis in plantsFrontiers in Plant Science