Laura Bacete
About
Cell wall integrity mechanisms are a hot topic of plant research, with many works published in the past ten years. Briefly, there are four hot questions on cell wall integrity:
- How are changes in cell wall integrity perceived?
- How do the composition and mechanical characteristics of cell walls change in different conditions?
- How do the plants integrate this information into their developmental processes?
- How can we use that to improve crops?
My PhD and past postdoc research have been focused on the first question, whereas my current research and the future prospects for my career aim to answer the rest. For that, I intent to use a series of methodologies I have previous experience with:
- Brillouin microscopy.
- Study of signalling cascades.
- Characterization of receptor-ligand interactions in silico and in vitro.
- Molecular Biology (cloning, qRT-PCR, RNAseq, etc.).
- Biochemical analysis (GC/LC-MS, FTIR, etc.).
- Cell wall fractionation and glycome profiling.
Prof. Hamann’s laboratory focuses its research on understanding how both cell wall integrity alterations and changes in turgor pressure levels are coordinated with each other and affect mechanical characteristics of cell walls, plant growth, and interactions with the environment. Still, a significant obstacle in this research area is the inability to detect changes in the mechanical characteristics of cell walls and/or turgor pressure levels in vivo induced by cell wall damage with appropriate temporal and spatial resolution. In addition, routinely used methods for analysing mechanical characteristics of plant cell walls like atomic force microscopy are restricted to surface cell layers like the epidermis. For these reasons, we decided to employ Brillouin Microscopy. It is based on the so-called Brillouin light scattering effect, i.e., the interaction between the incident light and the acoustic waves inside a sample, which leads to a frequency shift in the scattered light. Sample’s mechanical characteristics determine the propagation of the acoustic waves. Hence, the observed frequency shift can be related to the sample’s longitudinal modulus of elasticity, allowing the quantification of the material’s stiffness. I have used the Brillouin microscopy approach to examine the consequences of manipulation of cell wall biosynthesis inhibition using ISX and turgor levels (hyperosmotic conditions) on the mechanical characteristics of root cell walls. The preliminary results showed that this technique could detect changes in cell wall stiffness after different treatments in wild-type plants. As a confirmation of the effectivity of the technique, the cell wall stiffness in mutant ixr1-1, which is not affected by ISX, did not change after ISX treatment. My results using the1-1 knock-out mutant and the1-4 gain-of-function mutant demonstrated that THE1 is required for coordinating changes in mechanical properties of cell walls in response to these stimuli. Previous data suggested THE1 was coordinating processes involving cell expansion, displacement of plasma membrane versus cell wall (cell wall weakening after ISX treatment) and processes concerning the distortion of the cell wall-plasma membrane continuum associated with cell shrinkage (hyperosmotic stress). To complement the Brillouin microscopy data, I studied downstream signalling processes mediated by phytohormones quantified using LC-MS. By integrating these results, we have developed a model explaining how a plant cell could generate specific responses to either cell expansion and shrinkage, based on interactions between the plant cell wall and plasma membrane. My current position includes the self-management of research funds and interests. And in summary, the first publication derived from it represents my research style: it is an interdisciplinary work in which we applied novel methodologies to solve problems (in this case, limitations on the techniques measuring mechanical characteristics of cell walls).
I have an International PhD in Plant and Associated Microorganisms Biotechnology and Genetic Resources. I obtained it from the Universidad Politécnica de Madrid (Technical University of Madrid). I obtained it with a summa cum laude mention. A year later, my PhD thesis was selected as one of the best PhD thesis defended during 2018, being the only awarded thesis in the Department of Biotechnology.
My publication record includes ten peer-reviewed papers, one book chapter, three oral presentations at international conferences, three poster presentations at international conferences, fifteen peer-reviewed conference abstracts. Some selected publications and their impact on the field are listed below:
Bacete, L., Schulz, J., Engelsdorf, T., Bartosova, Z., Tichá, T., Vaahtera, L., Yan, G., Gerhold, J., Øvstebø, C., Gigli-Bisceglia, N., Margueritat, J., Kollist, H., Dehoux, T., McAdam, S.A.M., Hamann., T. (2022) THESEUS1 modulates mechanical characteristics of cell walls and abscisic acid production in Arabidopsis thaliana. PNAS, 119 (1) e2119258119. DOI: 10.1073/pnas.2119258119.
- One of the first applications of Brillouin Microspectroscopy in plants. We used this novel technique to study changes in biophysical characteristics of A. thaliana cell walls in response to cell wall damage and hyperosmotic pressure conditions.
- To complement the Brillouin data, we studied downstream signaling processes mediated by phytohormones quantified using LC-MS/MS.
- By integrating these results, we have developed a model explaining how a plant cell could generate specific responses to either cell expansion and shrinkage, based on interactions between the plant cell wall and plasma membrane.
Molina, A., Miedes, E., Bacete, L., Rodríguez, T., Mélida, H., Denancé, N., Sánchez-Vallet, A., Rivieré, M.P., López, G., Freydier, A., Bartel, X., Pattathil, S., Hahn, M. and Goffner, D. (2021) Arabidopsis cell wall composition determines disease resistance specificity and fitness. PNAS 118(5). DOI: 10.1073/pnas.2010243118
- Interdisciplinary work using mathematical modelling and biochemical analysis to link Arabidopsis thalianamutants with alterations in cell wall composition to improvement in resistance to biotic / abiotic stress.
Bacete, L., Miedes, E., Mélida, H., López, G., Denancé, N., Marco, Y. and Molina, A. (2020) ARABIDOPSIS RESPONSE REGULATOR 6 (ARR6) affects cell wall composition and mediates resistance to Plectosphaerella cucumerina and Ralstonia solanacearum. MPMI 33(5). DOI: 10.1094/MPMI-12-19-0341-R
- ARR6 was believed to act exclusively as a mediator of the plant’s hormonal responses. However, in this work we demonstrated ARR6 is also involved in the control of cell-wall composition and disease resistance, which stated the role of the plant cell wall in the modulation of specific immune responses.
- Selected as Editor’s Pick for September 2020 issue of MPMI Journal.
- Top cited paper in MPMI Journal during 2020.
Mélida, H., Bacete, L., Ruprecht, C., Rebaque, D., Del Hierro, I., López, G., Bunner, F., Pfrengle, F. and Molina, A. (2020). Arabinoxylan-oligosaccharides act as Damage Associated Molecular Patterns in plants regulating disease resistance. Front. Plant. Sci. 11, 1210. DOI: 10.3389/fpls.2020.01210
- Continuation of the research done during my PhD.
- Using cell wall fractions extracted from the arr6 mutant, we were able to identify an arabinoxylan pentasaccharide with strong immunomodulatory activity.
- In this work, we propose 33-α-l-arabinofuranosyl-xylotetraose (XA3XX) as a hemicellulose-derived DAMP triggering strong immune responses in Arabidopsis thaliana and enhancing crop disease resistance.
Bacete, L., Mélida, H., Miedes, E. and Molina, A. (2018) Plant cell wall-mediated immunity: cell wall changes trigger disease resistance responses. Plant J., 93, 614. DOI: 10.1111/tpj.13807
- State-of-science review about the prominent role of plant cell wall in defense to pathogens.
- Ranked in the top 20 most downloaded articles in The Plant Journal during 2018.
Gonneau, M., Desprez, T., Martin, M., Doblas, V.N.G., Bacete, L., Miart, F., Sormani, R., Hematy, K., Renou, J., Landrein, B., Evan, M., Van De Cotte, B., Vernhettes, S., De Smet, I. and Höfte, H. (2018) Receptor Kinase THESEUS1 is a RALF34 receptor in Arabidopsis. Curr. Biol., 28, 1. DOI: 10.1016/j.cub.2018.05.075
- Reference work about the role of the A. thaliana receptor kinase THE1 in the perception of the signaling peptide RALF34 composing a network that integrates cell wall integrity with the coordination of different physiological processes.
Other publications and selected conference presentations can be found in my CV, which is available here.
My Postdoctoral contract at the Norwegian University of Science and Technology is associated with a 1000 h teaching quota. I started to fulfil that requirement a few months after starting in 2019 as a teaching assistant in the Molecular Biology Lab course (BI2015) included in Bachelor and Master programs in Biology and Biotechnology. BI2015 is an intensive hands-on lab course (two weeks full time) that trains students in using standard Molecular Biology protocols and provides a brief introduction to the theoretical foundations of the methods. Groups of 20 students divided into pairs learn essential methodologies like PCR, GATEWAY-based cloning, CRISPR-Cas9, protein expression/purification, phytohormone quantification using an LC-MS based method, image analysis and statistics. For evaluation, the students need to write reports in form of short scientific publications and pass a final written exam to evaluate their theoretical knowledge. In 2021 and 2022, I have been the coordinator of this course. This responsibility includes lecturing, practical supervision, and administrative duties: design of course evaluation guidelines, establishing the number of students and access criteria, coordination with other courses, etc. Moreover, for this year I have performed a complete reformulation of the course to make it more collaborative and accessible to students. I have developed a cohesive course in which the different techniques learned in each module complement each other, achieving a higher level of integration. This was usually mentioned in the satisfaction surveys as a course weakness. Essentially, I want my students to improve their ability to investigate and solve scientific problems by i) formulating pertinent research questions, ii) learning how to design experiments and organize their own time, and iii) processing and interpreting results. I also want them to work in teams to understand the need for collaboration in research. They need to share the results between groups to successfully proceed with the course and write the final reports imitating a scientific publication. I have also introduced a small “journal club” in which the students will present a scientific publication related to the course to their classmates to introduce them to scientific literature.
Moreover, I have collaborated as a teaching assistant in the Cell Biology course (BI2012) in 2020 and 2021 included in the same programs. In this course, the students (in groups from three to five) need to work on a project in a research laboratory environment. My tasks were to supervise these groups, showing them different research methodologies that we commonly use in the lab and evaluate the reports in the form of scientific papers produced by the students. Currently, in the Spring Semester of the 2021/2022 academic year, I am a lecturer in the BI2012 Cell Biology course.
I have officially supervised the following master projects:
- 2021 – 2022: “Characterization of the role of different transcription factors involved in Arabidopsis thaliana cell wall integrity maintenance”. Ms. Eline Hildrum. NTNU.
- 2020: “Evaluation of ethylene-related phenotypes in arr6 mutants”. Ms. Carolina Pizarro Gómez. UPM/ Universidad CEU San Pablo. Awarded the highest grade.
Moreover, I have informally supervised four PhD students and two more Master students. I believe I have deeply contributed to their formation by teaching methods, supervising experiment design and proofreading their drafts, despite not being able to officially supervise them because of regulation circumstances. Furthermore, I am proud to say that the relationship with my mentees was a friendly one, and in many cases we have kept the contact even after their degree’s completion.
Publications
2022
-
Bacete, Laura;
Schulz, Julia;
Engelsdorf, Timo;
Bartosova, Zdenka;
Vaahtera, Lauri;
Yan, Guqi.
(2022)
THESEUS1 modulates cell wall stiffness and abscisic acid production in Arabidopsis thaliana.
Proceedings of the National Academy of Sciences of the United States of America (PNAS)
Academic article
2021
-
Rebaque, Diego;
del Hierro, Irene;
López, Gemma;
Bacete, Laura;
Vilaplana, Francisco;
Dallabernardina, Pietro.
(2021)
Cell wall-derived mixed-linked β-1,3/1,4-glucans trigger immune responses and disease resistance in plants.
The Plant Journal
Academic article
-
Nymark, Marianne;
Völker, Johannes ;
Ticha, Tereza;
Ashcroft, Felicity;
Bartosova, Zdenka;
Serif, Manuel.
(2021)
NTNU-forskere plukket plast.
Fosna-Folket
Popular scientific article
2020
-
Bacete, Laura;
Melida, Hugo;
Lopez, Gemma;
Dabos, Patrick;
Tremousaygue, Dominique;
Denance, Nicolas.
(2020)
Arabidopsis response reGUlator 6 (ARR6) modulates plant cell-wall composition and disease resistance.
Molecular Plant-Microbe Interactions
Academic article
-
Bacete, Laura;
Hamann, Thorsten.
(2020)
The role of mechanoperception in plant cell wall integrity maintenance.
Plants
Academic literature review
-
Hamann, Thorsten;
Bacete, Laura.
(2020)
Plant Biology: Plants Turn Down the Volume to Respond to Cell Swelling. .
Current Biology
Academic literature review
Journal publications
-
Bacete, Laura;
Schulz, Julia;
Engelsdorf, Timo;
Bartosova, Zdenka;
Vaahtera, Lauri;
Yan, Guqi.
(2022)
THESEUS1 modulates cell wall stiffness and abscisic acid production in Arabidopsis thaliana.
Proceedings of the National Academy of Sciences of the United States of America (PNAS)
Academic article
-
Rebaque, Diego;
del Hierro, Irene;
López, Gemma;
Bacete, Laura;
Vilaplana, Francisco;
Dallabernardina, Pietro.
(2021)
Cell wall-derived mixed-linked β-1,3/1,4-glucans trigger immune responses and disease resistance in plants.
The Plant Journal
Academic article
-
Nymark, Marianne;
Völker, Johannes ;
Ticha, Tereza;
Ashcroft, Felicity;
Bartosova, Zdenka;
Serif, Manuel.
(2021)
NTNU-forskere plukket plast.
Fosna-Folket
Popular scientific article
-
Bacete, Laura;
Melida, Hugo;
Lopez, Gemma;
Dabos, Patrick;
Tremousaygue, Dominique;
Denance, Nicolas.
(2020)
Arabidopsis response reGUlator 6 (ARR6) modulates plant cell-wall composition and disease resistance.
Molecular Plant-Microbe Interactions
Academic article
-
Bacete, Laura;
Hamann, Thorsten.
(2020)
The role of mechanoperception in plant cell wall integrity maintenance.
Plants
Academic literature review
-
Hamann, Thorsten;
Bacete, Laura.
(2020)
Plant Biology: Plants Turn Down the Volume to Respond to Cell Swelling. .
Current Biology
Academic literature review