KELLER Harald

Education

Current and previous postions

Main scientific focus

My scientific interest is to identify the molecular mechanisms that underly plant susceptibility to phytopathogenic oomycetes. The laboratory conducts research in the fields of functional genomics, genetics, biochemistry, and molecular and cell biology. The studies focus on two biological systems involving the model plantArabidopsis thalianaas a host, and the oomycete pathogens:

• Hyaloperonospora arabidopsidis, an obligatory biotrophic oomycete causing mildew disease on leaves. This pathogen is specialised on its host plant Arabidopsis.
• Phytophthora parasitica, a hemi-biotrophic oomycete, which attacks the roots of Arabidopsis. This pathogen is polyphagous. It initiates infection through a biotrophic phase and subsequently triggers plant cell death.

We perform functional analysis of genes of A. thaliana whose expression levels affect the interaction with H. arabidopsidis. We identified two genes encoding "leucine-rich repeat receptor-like kinases" (LRR-RLKs), a gene encoding a putative negative regulator of cell death, a gene encoding a microtubule-associated protein involved in mitosis, and two genes encoding transferases, an UDP-glucosyltransferase and a methyltransferase involved in the synthesis of monolignols (COMT1).

The model pathosystem between A. thaliana and Phytophthora parasitica was established in our laboratory. This is the first pathosystem involving the model plant and a hemibiotrophic oomycete root pathogen. The compatible interaction is characterized by a prolonged biotrophic phase, which is essential for the life cycle of P. parasitica, but difficult to observe during infection of natural hosts, such as tomato. To describe the transcriptome of infected roots at different stages, from penetration to the outbreak of necrotrophy, we performed extensive µ-array analyses, and initiated the functional analysis of selected candidate genes.

Research projects

• National Research Agency (ANR) projects: ANR Génoplante AFINDIS  2006-2008, and ANR Génomique SCRIPS 2009-2012. The aim of theses projects was identifying common host targets for three unrelated pathogens (oomycetes, the nematode Meloidogyne incognita, and the bacterium Ralstonia solanacearum.)
• Valorisation (Génoplante Valor, 2011-2013). An ongoing project aims at showing that the inactivation of a host gene in tomato by TILLING confers broad-spectrum resistance. The gene to be tilled is the ortholog of an Arabidopsis gene that we identified in the course of the above mentioned projects.
• The analysis of host targets for oomycete pathogens is integrated in the ANR LabEx “Signalife”.

Teaching

Specialized courses and practical training in the frame of the Master program Biology of Adaptation, Module Interactions between Plants and Bioagressors, University of Nice-Sophia Antipolis (since 2004). Frequent invitations from other French Universities for seminars in the frame of Master courses (Toulouse, Rouen).

Expertises

• Member of National and International grant evaluation panels (ANR France, DFG Germany, NOW The Netherlands, FWF Austria).
• Member of National panels for the evaluation of Scientists (CSS France), Research Units, and Institutes (AERES France).
• President of the Scientific Council of the Labex (Laboratory of Excellence) Signalife.
• Referee of scientific journals such asPlant Journal, Plant Physiology, Mol. Plant Microbe Interact., etc.
• Organisation of three workshops in the frame of theFOR666 Annual Meetings on Compatibility Mechanisms(2006, 2009, and 2011 in Sophia Antipolis.
• Member of the Scientific Council of the conference cycle (every two years)Journées Jean Chevaugeon: Rencontres de Mycologie-Phytopathologie(since 2011).

Laboratory members

• Valerie Allasia, Technician (TR) INRA
• Master and PhD students

Recent and significant publications/patents

• Galli M, Jacob S, Zheng Y, Ghezellou P, Gand M, Albuquerque W, Imani J, Allasia V, Coustau C, Spengler B, Keller H, Thines E, Kogel K-H (2023). MIF-like domain containing protein orchestrates cellular differentiation and virulence in the fungal pathogen Magnaporthe oryzae. iScience 26, 107565. https://doi.org/10.1016/j.isci.2023.107565
• Giordano L, Schimmerling M, Panabières F, Allasia V, Keller H (2022). The exodomain of the impaired oomycete susceptibility 1 receptor mediates both endoplasmic reticulum stress responses and abscisic acid signalling during downy mildew infection of Arabidopsis. Mol Plant Pathol, 23, 1783-1791.https://doi.org/10.1111/mpp.13265
• Giordano L, Allasia V, Cremades A, Hok S, Panabières F, Bailly-Maître B, Keller H (2022). A plant receptor domain with functional analogies to animal malectin disables ER stress responses upon infection. iScience 25, 103877. https://doi.org/10.1016/j.isci.2022.103877
• Gruner K, Leissing F, Sinitski D, Thieron H, Axstmann C, Baumgarten K, Reinstädler A, Winkler P, Altmann M, Flatley A, Jaouannet M, Zienkiewicz K, Feussner I, Keller H, Coustau C, Falter-Braun P, Feederle R, Bernhagen J, Panstruga R (2021). Chemokine-like MDL proteins modulate flowering time and innate immunity in plants. J Biol Chem 296, 100611. https://doi.org/10.1016/j.jbc.2021.100611
• Lebeaupin C, Blanc M, Vallée D, Keller H, Bailly-Maitre B (2020). BAX inhibitor-1: between stress and survival. FEBS J. 287, 1722-1736. https://doi.org/10.1111/febs.15179
• Jaouannet M, Pavaux AS, Pagnotta S, Pierre O, Michelet C, Marro S, Keller H, Lemée R, Coustau C (2020). Atypical membrane-anchored cytokine MIF in a marine dinoflagellate. Microorganisms 8, 1263. https://doi.org/10.3390/microorganisms8091263
• Testi S, Cazareth J, Keller H, Panabières F (2019). An oomycete effector impairs autophagy in evolutionary distant organisms and favors host infection. bioRxiv https://doi.org/10.1101/697136 
• Michelet C, Danchin EGJ, Jaouannet M, Bernhagen J, Panstruga R, Kogel KH, Keller H, Coustau C (2019). Cross-kingdom analysis of diversity, evolutionary history and site selection within the eukaryotic MIF protein superfamily. Genes 10, 740.
• Allasia V, Industri B, Ponchet M, Quentin M, Favery B, Keller H (2018). Quantification of salicylic acid (SA) and SA-glucosides in Arabidopsis thaliana. Bio-Protocol 8, 1-8.
• Le Berre JY, Gourgues M, Samans B, Keller H, Panabières F, Attard A (2017). Transcriptome dynamic of Arabidopsis roots infected with Phytophthora parasitica identifies VQ29, a gene induced during the penetration and involved in the restriction of infection. PLoS One 12, e0190341.
• Hanemian M, Barlet X, Sorin C, Yadeta KA, Keller H, Favery B, Simon R, Thomma BPHJ, Hartmann C, Crespi M, Marco Y, Tremousaygue D, Deslandes L (2016). Arabidopsis CLAVATA1 and CLAVATA2 receptors contribute to Ralstonia solanacearum pathogenicity through a miR169-dependent pathway. New Phytol 211, 502-515.
• Quentin M, Baurès I, Hoefle C, Caillaud MC, Allasia V, Panabières F, Abad P, Hückelhoven R, Keller H, Favery B (2016).  The Arabidopsis microtubule-associated protein MAP65-3 supports infection by filamentous biotrophic pathogens
• Naessens E, Dubreuil G, Giordanengo P, Baron OL, Minet-Kebdani N, Keller H, et Coustau C (2015). A secreted MIF cytokine enables aphid feeding and represses plant immune responses. Curr. Biol. 25, 1898-1903.
• Hok S, Allasia V, Andrio E, Naessens E, Ribes E, Panabières F, Attard A, Clément M, Barlet X, Marco Y, Grill E, Eichmann R, Weis C, Hückelhoven R, Ammon A, Ludwig-Müller J, Voll LM, Keller H (2014). The receptor kinase Impaired Oomycete Susceptibility 1 attenuates abscisic acid responses in Arabidopsis. Plant Physiol. 166, 1506-1518.
• Koch A, Kumar N, Weber L, Keller H, Imani J, Kogel KH (2013). Host-induced gene silencing of cytochrome P450 lanosterol C14α-demethylase-encoding genes confers strong resistance to Fusarium species. Proc. Natl. Acad. Sci. U S A 110, 19324-19329.
• Mosher S, Seybold H, Rodriguez P, Stahl M, Davies KA, Dayaratne S, Morillo S, Wierzba M, Favery B, Keller H, Tax FE, Kemmerling B (2012). The Tyrosine-sulfated peptide receptors PSKR1 and PSY1R modify Arabidopsis immunity to biotrophic and necrotrophic pathogens in an antagonistic manner. Plant J. 73, 469-482.
• Rodiuc N, Marco Y, Favery B, et Keller H (2012). Plants resistant to pathogens and methods for production thereof. Brevet WO/2012/017067.
• Hok S, Danchin EG, Allasia V, Panabières F, Attard A, et Keller H (2011). An Arabidopsis (malectin-like) leucine-rich repeat receptor-like kinase contributes to downy mildew disease. Plant Cell Environ.34, 1944-1957.
• Attard A, Gourgues M, Callemeyn-Torre N, et Keller H (2010). The immediate activation of defense responses in Arabidopsis roots is not sufficient to prevent Phytophthora parasitica infection. New Phytol.187, 449-460.
• Hok S, Attard A, et Keller H (2010). Getting the most from the host: how pathogens force plants to cooperate in disease. Mol. Plant-Microbe Interact.23, 1253–1259.
• Engelhardt S, Lee J, Gäbler Y, Kemmerling B, Haapalainen ML, Li CM, Wei Z, Keller H, Joosten M, Taira S, et Nürnberger T (2009). Separable roles of the Pseudomonas syringae pv.phaseolicola accessory protein HrpZ1 in ion-conducting pore formation and activation of plant immunity.Plant J.57, 706-717.
• Quentin M, Allasia V, Pegard A, Allais F, Ducrot PH, Favery B, Levis C, Martinet S, Masur C, Ponchet M, Roby D, Schlaich NL, Jouanin L, et Keller H (2009). Imbalanced lignin biosynthesis promotes the sexual reproduction of homothallic oomycete pathogens. PLoS Pathog.5, e1000264.
• Attard A, Gourgues M, Galiana E, Panabières F, Ponchet M, et Keller H (2008). Strategies of attack and defense in plant-oomycete interactions, accentuated for Phytophthora parasitica Dastur (syn.P. nicotianaeBreda de Haan). J. Plant Physiol.165, 83-94.
• Hernández-Blanco C, Feng DX, Hu J, Sánchez-Vallet A, Deslandes L, Llorente F, Berrocal-Lobo M, Keller H, Barlet X, Sánchez-Rodríguez C, Anderson LK, Somerville S, Marco Y, et Molina A (2007). Impairment of cellulose synthases required for Arabidopsis secondary cell wall formation enhances disease resistance. Plant Cell 19, 890-903.
• Racapé J, Belbahri L, Engelhardt S, Lacombe B, Lee J, Lochman J, Marais A, Nicole M, Nürnberger T, Parlange F, Puverel S, et Keller H (2005). Ca2+-dependent lipid binding and membrane integration of PopA, a harpin-like elicitor of the hypersensitive response in tobacco.Mol. Microbiol.58, 1406–1420.
• Belbahri L, Boucher C, Candresse T, Nicole M, Ricci P, et Keller H (2001). A local accumulation of theRalstonia solanacearumPopA protein in transgenic tobacco renders a compatible plant-pathogen interaction incompatible. Plant J.28, 419-430.
• Keller H, Pamboukdjian N, Ponchet M, Poupet A, Delon R, Verrier JL, Roby D, et Ricci P (1999). Pathogen-induced elicitin production in transgenic tobacco generates a hypersensitive response and nonspecific disease resistance. Plant Cell11, 223-236.