José J. Sánchez Serrano
Group Leader
Enrique Rojo
Group Leader
Research summary
In our group we are interested in understanding how the progeny from stem cells decides between retaining pluripotency or initiating cell differentiation. We have characterized two genes in Arabidopsis, IYO and RIMA, which are core components of a switch activating cell differentiation in plants. We are now studying how this switch is regulated by developmental and extrinsic signals and what output of the switch is responsible for triggering differentiation. In addition to improving our understanding of plant development, our research could provide technology for targeting important traits such as organogenesis or regeneration capacity.
Publications
Taurino, M., Costantini, S., De Domenico, S., Stefanelli, F., Ruano, G., Delgadillo, M.O., Sanchez-Serrano, J.J., Sanmartin, M., Santino, A., and Rojo, E. SEIPIN Proteins Mediate Lipid Droplet Biogenesis to Promote Pollen Transmission and Reduce Seed Dormancy. Plant Physiol 2018 176, 1531-1546.
Lynch, C.J., Bernad, R., Calvo, I., Nobrega-Pereira, S., Ruiz, S., Ibarz, N., Martinez-Val, A., Grana-Castro, O., Gomez-Lopez, G., Andres-Leon, E., Espinosa Angarica, V., Del Sol, A., Ortega, S., Fernandez-Capetillo, O., Rojo, E., Munoz, J., and Serrano, M. The RNA Polymerase II Factor RPAP1 Is Critical for Mediator-Driven Transcription and Cell Identity. Cell Rep 2018, 22, 396-410.
Sánchez Serrano JJ. Plant responses to wounding. In: eLS, John Wiley & Sons Ltd, Chichester UK. 2017
Munoz, A., Mangano, S., Gonzalez-Garcia, M.P., Contreras, R., Sauer, M., De Rybel, B., Weijers, D., Sanchez-Serrano, J.J., Sanmartin, M., and Rojo, E. RIMA-Dependent Nuclear Accumulation of IYO Triggers Auxin-Irreversible Cell Differentiation in Arabidopsis. Plant Cell 2017 29, 575-588.
Creighton MT, Sanmartín M, Kataya ARA, Averkina IO, Heidari B, Nemie-Feyissa D, Sánchez-Serrano JJ, Lillo C. Light regulation of nitrate reductase by catalytic subunits of protein phosphatase 2A. Planta 2017, 246, 701-710.
Plants adjust their development to accommodate cell differentiation and growth to fluctuating environmental conditions. Intricate signalling networks translate environmental cues into reprogramming of gene expression as a major adaptive response to biotic and abiotic stresses.
Stem cell differentiation implies large-scale transcriptional modifications. We have identified the RNA polymerase II (Pol II) phosphatase ART and its interacting partner MINIYO (IYO) as essential factors for initiating cell differentiation in Arabidopsis. Our results suggest that coupled uptake of ART and IYO into the nucleus switches on this cell fate transition through direct regulation of Pol II gene transcription.
Reversible protein phosphorylation is a common molecular switch in signalling pathways. Protein phosphatases 2A (PP2A) dephosphorylate proteins at serine/threonine residues. PP2A is a heterotrimer consisting of a catalytic (PP2A-C), a scaffold (PP2A-A), and a regulatory (PP2A-B) subunit. The Arabidopsis genome codes for five very similar PP2A-C proteins. These are grouped in subfamily 1 (PP2A-C1, ‑C2, and -C5) and subfamily 2 (PP2A-C3 and -C4). Whilst single pp2ac-3 and pp2ac-4 mutant lines do not display any obvious phenotype, pp2ac-3pp2ac-4 plantlets are severely misshapen, with severe malformations of cotyledon and root primordia. Our results indicate that PP2A-C3 and PP2A-C4 have redundant functions in controlling embryo patterning and root development, processes that depend on auxin fluxes. Moreover, polarity of the auxin efflux carrier PIN1 and auxin distribution are both affected by mutations in PP2A-C3 and PP2A-C4. Our work shows functional specialisation of subfamily 2 in the regulation of PIN protein polarity and hence, of auxin fluxes and plant patterning.
Following attack by pests and/or pathogens, plants turn on inducible defence responses that entail large changes in transcriptional profiles. A major wound-signalling pathway involves jasmonic acid (JA). Large, transient increases in endogenous JA levels occur after mechanical damage, and high JA levels trigger the transcriptional activation of defence genes. In potato, two genes (StAOS1 and StAOS2) encode the putative 13-AOS which catalyses the first committed step in JA biosynthesis. We showed that StAOS1 and StAOS2 must be cosuppressed simultaneously to lower plant JA levels significantly, resulting in altered cell wall structure and increased susceptibility to pathogens.
