TY  - JOUR
AB  - RHO (rat sarcoma homologue) GTPases (guanosine triphosphatases) are regulators of downstream transcriptional responses of eukaryotes to intracellular and extracellular stimuli. For plants, little is known about the function of Rho-like GTPases [called RACs (rat sarcoma-related C botulinum substrate) or ROPs (RHO of plants)] in transcriptional reprogramming of cells. However, in plant hormone response and innate immunity, RAC/ROP proteins influence gene expression patterns. The barley RAC/ROP RACB is required for full susceptibility of barley to the powdery mildew fungus Blumeria graminis f.sp. hordei (Bgh). We compared the transcriptomes of barley plants either silenced for RACB or over-expressing constitutively activated RACB with and without inoculation with Bgh. This revealed a large overlap of the barley transcriptome during the early response to Bgh and during the over-expression of constitutively activated RACB. Global pathway analyses and stringent analyses of differentially expressed genes suggested that RACB influences, amongst others, the expression of signalling receptor kinases. Transient induced gene silencing of RACB-regulated signalling genes (a leucine-rich repeat protein, a leucine-rich repeat receptor-like kinase and an S-domain SD1-receptor-like kinase) suggested that they might be involved in RACB-modulated susceptibility to powdery mildew. We discuss the function of RACB in regulating the transcriptional responses of susceptible barley to Bgh.
AU  - Schnepf, V.*
AU  - Vlot, A.C.
AU  - Kugler, K.G.
AU  - Hückelhoven, R.*
C1  - 52376
C2  - 43924
CY  - Hoboken
SP  - 393-404
TI  - Barley susceptibility factor RACB modulates transcript levels of signalling protein genes in compatible interaction with Blumeria graminis f.sp hordei.
JO  - Mol. Plant Pathol.
VL  - 19
IS  - 2
PB  - Wiley
PY  - 2018
SN  - 1464-6722
ER  - 

TY  - JOUR
AB  - Folates are essential for one-carbon transfer reactions in all organisms and contribute for example to de novo DNA synthesis. Here, we detected the folate precursors 7,8-dihydropteroate (DHP) and 4-amino-4-deoxychorismate (ADC) in extracts from Arabidopsis thaliana plants by Fourier transform ion cyclotron resonance mass spectrometry. The accumulation of DHP but not ADC was induced after infection of plants with Pseudomonas syringae delivering the effector protein AvrRpm1. Application of folic acid or the DHP precursor 7,8-dihydroneopterin enhanced resistance in Arabidopsis to P. syringae and elevated the transcript accumulation of the salicylic acid (SA) marker gene PATHOGENESIS-RELATED1 both in the treated and systemic untreated leaves. DHN- and folic acid-induced systemic resistance was dependent on SA biosynthesis and signaling. Similarly to SA, folic acid application locally enhanced Arabidopsis susceptibility to the necrotrophic fungus Alternaria brassicicola. Together, the data associate the folic acid pathway with innate immunity in Arabidopsis, simultaneously activating local and systemic SA-dependent resistance to P. syringae and suppressing local resistance to A. brassicicola.
AU  - Wittek, F.
AU  - Kanawati, B.
AU  - Wenig, M.
AU  - Hoffmann, T.*
AU  - Franz-Oberdorf, K.*
AU  - Schwab, W.*
AU  - Schmitt-Kopplin, P.
AU  - Vlot, A.C.
C1  - 32640
C2  - 35294
CY  - Hoboken
SP  - 616-622
TI  - Folic acid induces salicylic acid-dependent immunity in Arabidopsis and enhances susceptibility to Alternaria brassicicola.
JO  - Mol. Plant Pathol.
VL  - 16
IS  - 6
PB  - Wiley-blackwell
PY  - 2015
SN  - 1464-6722
ER  - 

TY  - JOUR
AB  - Bacterial lipopolysaccharides (LPS) are triggers of defence responses in plants, and induce local as well as systemic acquired resistance. Arabidopsis thaliana plants pretreated with LPS show an increased resistance to the virulent bacterial plant pathogen Pseudomonas syringae pv. tomato DC3000. To investigate the mobilization and transport of LPS in Arabidopsis leaves, fluorescently labelled LPS (Alexa Fluor® 488 conjugate) from Salmonella minnesota was used. Leaves were pressure infiltrated with fluorescein-labelled LPS and fluorescence microscopy was used to follow the movement and localization of LPS as a function of time. The observation of leaves 1 h after supplementation with fluorescein-labelled LPS revealed a fluorescent signal in the intercellular space. Capillary zone electrophoresis was used for the detection and analysis of the labelled LPS in directly treated leaves and systemic leaves. In addition, gel electrophoresis was used to confirm LPS mobilization. The results indicated that LPS mobilization/translocation occurs through the xylem from local, treated leaves to systemic, untreated leaves. Consequently, care should be taken when ascribing the observed biochemical responses and induced resistance from LPS perception as being uniquely local or systemic, as these responses might overlap because of the mobility of LPS in the plant vascular system.
AU  - Zeidler, D.
AU  - Dubery, I.A.*
AU  - Schmitt-Kopplin, P.
AU  - von Rad, U.
AU  - Durner, J.
C1  - 3400
C2  - 27565
SP  - 747-755
TI  - Lipopolysaccharide mobility in leaf tissue of Arabidopsis thaliana.
JO  - Mol. Plant Pathol.
VL  - 11
IS  - 6
PB  - Wiley-Blackwell Publishing, Inc.
PY  - 2010
SN  - 1464-6722
ER  -