Identification of tomato phosphatidylinositol-specific phospholipase-C (PI-PLC) family members and the role of PLC4 and PLC6 in HR and disease resistance

• Published in: The Plant journal : for cell and molecular biology Vol. 62; no. 2; pp. 224 - 239
• Main Authors: Vossen, Jack H, Abd-El-Haliem, Ahmed, Fradin, Emilie F, van den Berg, Grardy C.M, Ekengren, Sophia K, Meijer, Harold J.G, Seifi, Alireza, Bai, Yuling, ten Have, Arjen, Munnik, Teun, Thomma, Bart P.H.J, Joosten, Matthieu H.A.J
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01-04-2010; Blackwell Publishing Ltd
• Subjects: arabidopsis-thaliana; cell-death; Cladosporium; Cladosporium fulvum; Cloning, Molecular; diacylglycerol pyrophosphate; Disease resistance; DNA, Complementary - genetics; DNA, Plant - genetics; Escherichia coli; Gene Expression Regulation, Plant; Gene Knockdown Techniques; Gene regulation; Gene Silencing; Hypersensitive response; Immune response; Immunity, Innate; Infection; innate immunity receptors; Lycopersicon esculentum; moss physcomitrella-patens; Multigene Family; Nicotiana - enzymology; Nicotiana - genetics; Nicotiana - immunology; Nicotiana benthamiana; nucleotide-binding leucine-rich repeat; Pathogens; Perception; Perceptions; phosphatidic-acid; Phosphoinositide Phospholipase C - genetics; Phosphoinositide Phospholipase C - metabolism; Phospholipase C; phospholipid signalling; Phylogeny; Plant diseases; Plant Diseases - genetics; Plant Proteins - genetics; Plant Proteins - metabolism; Plants, Genetically Modified - genetics; Plants, Genetically Modified - immunology; Plants, Genetically Modified - metabolism; plasma-membrane; plc gene; pollen-tube growth; Pseudomonas syringae; receptor-like protein; Resistance to control; Sequence Analysis, DNA; Signal transduction; signaling pathways; Solanum; Solanum lycopersicum - enzymology; Solanum lycopersicum - genetics; Solanum lycopersicum - immunology; Transcription; Verticillium dahliae; virus-induced gene silencing
• ISSN: 0960-7412; 1365-313X; 1365-313X
• DOI: 10.1111/j.1365-313X.2010.04136.x

The perception of pathogen-derived elicitors by plants has been suggested to involve phosphatidylinositol-specific phospholipase-C (PI-PLC) signalling. Here we show that PLC isoforms are required for the hypersensitive response (HR) and disease resistance. We characterised the tomato [Solanum lycopersicum (Sl)] PLC gene family. Six Sl PLC-encoding cDNAs were isolated and their expression in response to infection with the pathogenic fungus Cladosporium fulvum was studied. We found significant regulation at the transcriptional level of the various SlPLCs, and SlPLC4 and SlPLC6 showed distinct expression patterns in C. fulvum-resistant Cf-4 tomato. We produced the encoded proteins in Escherichia coli and found that both genes encode catalytically active PI-PLCs. To test the requirement of these Sl PLCs for full Cf-4-mediated recognition of the effector Avr4, we knocked down the expression of the encoding genes by virus-induced gene silencing. Silencing of SlPLC4 impaired the Avr4/Cf-4-induced HR and resulted in increased colonisation of Cf-4 plants by C. fulvum expressing Avr4. Furthermore, expression of the gene in Nicotiana benthamiana enhanced the Avr4/Cf-4-induced HR. Silencing of SlPLC6 did not affect HR, whereas it caused increased colonisation of Cf-4 plants by the fungus. Interestingly, Sl PLC6, but not Sl PLC4, was also required for resistance to Verticillium dahliae, mediated by the transmembrane Ve1 resistance protein, and to Pseudomonas syringae, mediated by the intracellular Pto/Prf resistance protein couple. We conclude that there is a differential requirement of PLC isoforms for the plant immune response and that Sl PLC4 is specifically required for Cf-4 function, while Sl PLC6 may be a more general component of resistance protein signalling.