In our recent work, we demonstrate that RPG is an essential factor to drive the assembly of and the recruitment of specific proteins into ‘infectosomes’. In addition, we apply FLIM microscopy to unambiguously discriminate between autofluorescence and true fluorophore signals.

Lace B, Su C, Invernot-Perez D, Rodriguez-Franco M, Vernié T, Batzenschlager M, Egli S, Liu CW, Ott T (2023)
RPG acts as a central determinant for infectosome formation and cellular polarization during intracellular rhizobial infections
eLife; https://doi.org/10.7554/eLife.80741 (open access)
pre-printed deposited at: bioRxiv; https://doi.org/10.1101/2022.06.03.494689 (open access)

In this study we demonstrate that the remorin protein SYMREM1 can function as a membrane topology scaffold. The protein does not only induce distinct membrane structures but stabilizes those efficiently in the absence of a cell wall.

Congratulations to our first author Chao Su and all other co-authors who contributed with all their expertise to this work! That was fun working with all of you.

This work also demonstrates the strength of our truly interdisciplinary Cluster of Excellence CIBSS.

Su C, Rodriguez-Franco M, Lace B, Nebel N, Hernandez-Reyes C, Liang P, Schulze E, Mymrikov EV, Gross NM, Knerr J, Wang H, Siukstaite L, Keller J, Libourel C, Fischer AAM, Gabor KE, Mark E, Popp C, Hunte C, Weber W, Wendler P, Stanislas T, Delaux PM, Einsle O, Grosse R, Römer W, Ott T (2023)
Stabilization of membrane topologies by proteinaceous remorin scaffolds
Nature Communications; 14:323 (open access)

Our newest work on transcellular progression of rhizobia is now out in Current Biology. Congratulations to Chao as the first author and all other team members for their contributions!

Su C, Zhang G, Rodriguez-France M, Hinnenberg R, Wietschorke J, Liang P, Yang W, Uhler L, Li X and Ott T (2023)
Transcellular progression of infection threads in Medicago truncatula roots is associated with locally confined cell wall modifications
Current Biology; 33:533-542

SUMMARY
The root nodule symbiosis with its global impact on nitrogen fertilization of soils is characterized by an intracellular colonization of legume roots by rhizobia. While the symbionts are initially taken up by morphologically adapted root hairs, rhizobia persistently progress within a membrane-confined infection thread through several root cortical and later nodular cell layers. Throughout this transcellular passaging, rhizobia have to repeatedly pass host plasma membranes and cell walls. Here, we investigated this essential process and describe the concerted action of one of the symbiosis-specific pectin methyl esterases (SyPME1) and the nodule pectate lyase NPL at the infection thread and transcellular passage sites. Their coordinated function mediates spatially confined pectin alterations in the cell-cell interface that result in the establishment of an apoplastic compartment where bacteria are temporarily released into and taken up from the subjacent cell. This process allows successful intracellular progression of infection threads through the entire root cortical tissue.

We greatly appreciate to be able to contribute with our EM expertise to the newest paper from Olaf Groß’ lab (Metabolism and Inflammation Research Group, Medical faculty), a true collaborative paper within our Cluster of Excellence CIBSS. Congratulations to the first author Emilia Neuwirt and all other co-authors.

Neuwirt E, Magnani G, Ćiković T, Wöhrle S, Fischer L, Kostina A, Flemming S, Fischenich NJ, Saller BS, Gorka O, Renner S, Agarinis C, Parker C, Boettcher A, Farady CJ, Kesselring R, Berlin C, Backofen R, Rodriguez-Franco M, Kreutz C, Prinz M, Tholen M, Reinheckel T, Ott T, Groß CJ, Jost PJ, Groß O (2023)
Screen for inflammasome activators identifies tyrosine kinase inhibitors that cause lysosomal damage and cell lysis to activate NLRP3
Science Signalling; 17(768):eabh1083 (open access)

We are grateful to have contributed to the most recent paper from Xia Li’s lab (Huazhong Agricultural University, China), where they describe the soybean B-type response regulator GmRR11d to interact with GmNSP1a. GmRR11d functions as a negative regulator of nodulation by inhibiting GmNIN1a expression.
Congratulations to all authors involved!

Chen J, Wang Z, Wang L, Hu L, Yan Q, Lu J, Ren Z, Hong Y, Ji H, Wang H, Wu X, Lin Y, Su C, Ott T, Li X (2022)
The B-type response regulator GmRR11d mediates systemic inhibition of symbiotic nodulation
Nature Communications; 13: 7661 (open access)

Congratulations to all authors to the newest publication of the Kleine-Vehn lab in eLife. We are happy that Marta, head of our EM unit, could contribute to this nice paper.

Dünser K, Schöller M, Rößling A-K, Löfke C, Xiao N, Pařízková B, Melnik S, Rodriguez-Franco M, Stöger E, Novák O, Kleine-Vehn J (2022)
Endocytic trafficking promotes vacuolar enlargements for fast cell
expansion rates in plants. eLife; https://doi.org/10.7554/eLife.75945

In this manuscript we show that the RPG protein is a central polarizing protein and organizes the so-called “infectosome” at the tip of progressing infection threads and in the nuclear periphery.

Although technically challenging, the application of FLIM imaging allowed us to discriminate fluorophores from autofluorescence in a scientifically sound way and to image infectosomes with highest precision.

Full article:

Lace B, Su C, Invernot-Perez D, Rodriguez-Franco M, Vernié T, Batzenschlager M, Egli S, Liu CW, Ott T (2022)
RPG acts as a central determinant for infectosome formation and cellular polarization during intracellular rhizobial infections
pre-printed deposited at: https://www.biorxiv.org/content/10.1101/2022.06.03.494689v2 (open access)

Good start into the new year. We are happy to be able to contribute to a recent paper published in Plant Science by the lab of Rameshwar Sharma from Hyderabad, India. Congratulations to all authors involved!

Gupta P, Rodriguez‐Franco M, Bodanapu R, Sreelakshmi Y, Sharma R (2022)
Phytoene synthase 2 in tomato fruits remains functional and contributes to abscisic acid formation
Plant Science; https://doi.org/10.1016/j.plantsci.2022.111177

Congratulations Sebastian and Casandra for your work on NIN-like proteins, which was just accepted in MPMI! Great to see a fully independent story conducted by the Schenk/Hernandez-Ryes family! And always with great evolutionary support by the Toulouse team of Pierre-Marc Delaux.

Read more here:

Hernández-Reyes C, Lichtenberg E, Keller J, Delaux PM, Ott T, Schenk ST (2021)
NIN-Like Proteins; interesting Players in Rhizobia-Induced Nitrate
Signaling Response during Interaction with Non-Legume Host Arabidopsis thaliana
accepted in Molecular Plant-Mircrobe Interactions
pre-print deposited at: bioRxiv; https://doi.org/10.1101/2020.09.08.287219 (open access)

Great to see Moira’s story on PCaP1 published open access now! We hosted Moira in our lab for several months and assisted in some of the microscopy work. Well done Moira, Benedetta and all other authors! Congratulations.

You can find the original article here:

Giovannoni M, Marti L, Ferrari S, Tanaka-Takada N, Maeshima M, Ott T, De Lorenzo G, Mattei B (2021)
The plasma membrane-associated Ca²⁺– binding protein PCaP1 is required for oligogalacturonide and flagellin-induced priming and immunity
Plant, Cell & Environment; https://doi.org/10.1111/pce.14118

We are delighted to be part of this exciting scientific journey undertaken by the team of Pierre-Marc Delaux as the leading lab and many other contributors. Congratulations to everyone for this great team effort.

Original publication:

Rich MK, Vigneron N, Libourel C, Keller J, Xue L, Hajheidari M, Radhakrishnan GV, Le Ru A, Issa Diop S, Potente G, Conti E, Duijsings D, Batut A, Le Faouder P, Kodama K, Kyozuka J, Sallet E, Bécard G, Rodriguez-Franco M, Ott T, Bertrand-Michel J, Oldroyd GED, Szövényi P, Bucher M, Delaux PM (2021).
Lipid exchanges drove the evolution of mutualism during plant terrestrialization.
Science; 372 (6544): 864-868